* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    text-decoration: none;
    font-family: var(--font-family-base);
}

a,
button {
    color: inherit;
    white-space: nowrap;
    cursor: pointer;
}

html {
    scroll-behavior: smooth;
    scroll-snap-stop: always;
    overflow-x: hidden;
    -webkit-overflow-scrolling: touch;
}

body {
    background-color: var(--color-bg-bottom);
    color: var(--color-text);
}

section > header {
    margin-bottom: var(--size-base);
}

header {
    display: flex;
    flex-direction: column;
    gap: var(--size-xs);
}

textarea {
    font-family: var(--font-family-base);
    resize: none;
}

.layout--error .main {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--size-max) 0;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    clip-path: inset(50%);
    white-space: nowrap;
    border: 0;
}

.layout--error .error {
    margin: 0 auto;
    width: min(100%, 640px);
}

.header {
    grid-area: header;
    height: var(--header-height);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: center;
    position: sticky;
    top: 0;
    background-color: var(--color-bg-top);
    z-index: 1000;
}

.header__nav {
    display: flex;
    align-items: center;
    gap: var(--common-gap);
    max-width: var(--page-max-width);
    justify-content: space-between;
    position: relative;
    padding-inline: var(--page-side-padding);
}

.header__logo {
    display: flex;
    align-items: center;
    justify-content: center;
    height: var(--size-md);
}

.header__logo .header__logo-image {
    height: var(--size-md);
    width: auto;
}

.header__logo-text {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: inherit;
    text-transform: none;
}

.header__theme-toggle {
    display: inline-flex;
    align-items: center;
    gap: var(--size-xs);
    border: 1px solid var(--color-border);
    background-color: transparent;
    color: var(--color-text);
    border-radius: 999px;
    padding: var(--size-xs) var(--size-sm);
    font-size: var(--font-size-sm);
    margin-left: var(--size-sm);
}

.header__theme-toggle:hover,
.header__theme-toggle:focus-visible {
    border-color: var(--color-primary);
    color: var(--color-primary);
    outline: none;
}

.header__theme-icon {
    line-height: 1;
}

.header__nav-list {
    display: flex;
    align-items: center;
    list-style: none;
}

@media (min-width: 768px) {
    .header__nav-list {
        margin-left: auto;
    }
}

.header__menu-toggle {
    display: none;
    align-items: center;
    gap: var(--size-xs);
    border: 1px solid transparent;
    background-color: transparent;
    color: var(--color-text);
    padding: var(--size-xs) var(--size-sm);
    cursor: pointer;
    font-size: var(--font-size-base);
}

.header__menu-icon {
    position: relative;
    display: inline-block;
    width: var(--size-mid);
    height: var(--size-min);
    background-color: currentColor;
    transition: background-color 0.2s ease;
}

.header__menu-icon::before,
.header__menu-icon::after {
    content: '';
    position: absolute;
    left: 0;
    width: var(--size-mid);
    height: var(--size-min);
    background-color: currentColor;
    transition: transform 0.2s ease, top 0.2s ease, opacity 0.2s ease;
}

.header__menu-icon::before {
    top: -6px;
}

.header__menu-icon::after {
    top: 6px;
}

.header.is-menu-open .header__menu-icon {
    background-color: transparent;
}

.header.is-menu-open .header__menu-icon::before {
    top: 0;
    transform: rotate(45deg);
}

.header.is-menu-open .header__menu-icon::after {
    top: 0;
    transform: rotate(-45deg);
}

.header__nav-link {
    color: var(--color-text);
    font-weight: 500;
    padding: var(--size-sm) var(--size-base);
    border: 1px solid transparent;
    background-color: transparent;
    font-size: var(--font-size-base);
}

.header__nav-link--active {
    border-color: var(--color-primary);
    color: var(--color-primary);
    background-color: var(--color-primary-transparent);
    font-weight: 600;
}

@media (max-width: 768px) {
    .header__menu-toggle {
        display: inline-flex;
    }

    .header__nav {
        align-items: center;
    }

    .header__nav-list {
        display: grid;
        position: absolute;
        top: var(--header-height);
        left: var(--common-gap);
        right: var(--common-gap);
        background-color: var(--color-bg-top);
        border: 1px solid var(--color-border);
    }

    .header__theme-toggle {
        margin-left: 0;
        height: var(--size-md);
        width: var(--size-md);
        display: flex;
        justify-content: center;
        align-items: center;
    }

    .header__theme-label {
        display: none;
    }

    .header__nav-list[hidden] {
        display: none;
    }

    .header__nav-link {
        display: flex;
        width: 100%;
        text-align: left;
        height: var(--size-lg);
        align-items: center;
    }
}

.header__nav-link:hover {
    color: var(--color-primary);
}

#logout-button {
    color: var(--color-error);
    font-size: var(--font-size-base);
}

#logout-button:hover {
    background-color: color-mix(
        in srgb,
        var(--color-error) 12%,
        transparent 88%
    );
    border: 1px solid var(--color-error);
}

.main {
    grid-area: main;
    display: grid;
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--size-xs);
    padding: 0.7rem 1.4rem;
    border: 1px solid transparent;
    background-color: transparent;
    color: var(--color-text);
    font-size: var(--font-size-base);
    font-weight: 600;
    letter-spacing: 0.01em;
}

.button:focus-visible {
    outline: 3px var(--color-primary);
    outline-offset: 2px;
}

.button--primary {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
    color: var(--color-primary-opposite);
}

.button--primary:hover {
    background-color: var(--color-primary-hover);
    border-color: var(--color-primary);
}

.button--secondary {
    background-color: transparent;
    border-color: var(--color-border);
    color: var(--color-secondary);
}

.button--secondary:hover {
    color: var(--color-text);
    border-color: var(--color-text);
}

.form-grid {
    display: grid;
    gap: var(--size-sm);
}

.form-field {
    display: grid;
    gap: var(--size-xs);
}

.form-field--checkbox {
    align-items: flex-start;
}

.form-field__label {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-secondary);
    letter-spacing: 0.01em;
}

.form-field__input {
    width: 100%;
    padding: 0.7rem 0.9rem;
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
    color: var(--color-text);
    font-size: var(--font-size-base);
}

.form-field__hint {
    font-size: var(--font-size-sm);
    color: color-mix(in srgb, var(--color-secondary) 70%, var(--color-text) 30%);
    line-height: 1.4;
}

.form-field__input:focus-visible {
    outline: none;
    border-color: var(--color-primary);
}

.form-field__input:disabled {
    background-color: color-mix(
        in srgb,
        var(--color-border) 30%,
        var(--color-bg-top) 70%
    );
    cursor: not-allowed;
    color: color-mix(
        in srgb,
        var(--color-secondary) 70%,
        var(--color-text) 30%
    );
}

textarea.form-field__input {
    min-height: 120px;
    line-height: 1.5;
}

.custom-select {
    position: relative;
    width: 100%;
}

.custom-select__native {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    pointer-events: none;
}

.custom-select__trigger {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--size-xs);
    width: 100%;
    padding: 0.7rem 0.9rem;
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
    color: var(--color-text);
    font: inherit;
    line-height: 1.4;
    cursor: pointer;
    transition: border-color 0.15s ease;
}

.custom-select__trigger:focus-visible,
.custom-select.is-open .custom-select__trigger {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-primary-transparent) 70%, transparent);
}

.custom-select__trigger[disabled],
.custom-select__trigger[aria-disabled="true"] {
    cursor: not-allowed;
    opacity: 0.6;
}

.custom-select__icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1rem;
    height: 1rem;
    flex-shrink: 0;
}

.custom-select__icon::before {
    content: "";
    display: block;
    width: 0.45rem;
    height: 0.45rem;
    border-right: 2px solid var(--color-secondary);
    border-bottom: 2px solid var(--color-secondary);
    transform: rotate(45deg);
    transition: transform 0.2s ease;
}

.custom-select.is-open .custom-select__icon::before {
    transform: rotate(-135deg);
}

.custom-select__options {
    position: fixed;
    inset: auto;
    z-index: 1200;
    margin: 0;
    padding: 0.35rem 0;
    list-style: none;
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
    box-shadow: 0 8px 24px rgba(15, 23, 42, 0.12);
    max-height: 16rem;
    overflow-y: auto;
    box-sizing: border-box;
}

.custom-select__options--open-above {
    transform-origin: bottom;
    box-shadow: 0 -8px 24px rgba(15, 23, 42, 0.12);
}

.custom-select__options:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

.custom-select__option {
    padding: 0.6rem 0.9rem;
    font-size: var(--font-size-base);
    color: var(--color-text);
    cursor: pointer;
}

.custom-select__option:hover,
.custom-select__option--active {
    background-color: var(--color-primary-transparent);
}

.custom-select__option--selected {
    font-weight: 600;
}

.custom-select__option--disabled {
    color: var(--color-secondary);
    cursor: not-allowed;
}

.custom-select__option--disabled:hover {
    background-color: transparent;
}

.form-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    gap: var(--size-sm);
    margin-bottom: var(--size-base);
}

.form-actions__link {
    color: var(--color-primary);
    font-size: var(--font-size-sm);
}

.form-actions__link:hover {
    text-decoration: underline;
}

.form-helper {
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.form-fieldset {
    border: 1px solid var(--color-border);
    padding: var(--size-base);
    display: grid;
    gap: var(--common-gap);
    background-color: var(--color-primary-transparent);
}

.form-legend {
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-secondary);
}

.checkbox {
    display: inline-flex;
    align-items: center;
    gap: var(--size-sm);
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.checkbox__input {
    width: 1.1rem;
    height: 1.1rem;
    border: 1px solid var(--color-border);
    appearance: none;
    display: grid;
    place-items: center;
    background-color: var(--color-bg-top);
    position: relative;
}

.checkbox__input:checked {
    border-color: var(--color-primary);
    background-color: var(--color-primary);
}

.checkbox__input::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0.35rem;
    height: 0.65rem;
    border: solid var(--color-primary-opposite);
    border-width: 0 0.18rem 0.18rem 0;
    transform: translate(-50%, -60%) rotate(45deg) scale(0.75);
    transform-origin: center;
}

.checkbox__input:not(:checked)::after {
    border: solid transparent;
}

.checkbox__input:focus-visible {
    outline: 3px solid var(--color-primary-transparent);
    outline-offset: 2px;
}

.checkbox__label {
    color: var(--color-secondary);
    line-height: 1.6;
    user-select: none;
}

.auth {
    display: flex;
    align-items: center;
    justify-content: center;
}

.auth__container {
    width: min(100%, 580px);
    display: grid;
    gap: var(--size-mid);
    padding: var(--size-max);
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
    margin-block: var(--size-max);
}

.auth[data-page='setup'] .auth__container {
    width: min(100%, 760px);
}

.auth__header {
    display: grid;
    gap: var(--size-xs);
}

.auth__title {
    font-size: clamp(1.9rem, 4vw, 2.4rem);
    font-weight: 700;
    letter-spacing: -0.01em;
}

.auth__subtitle {
    font-size: var(--font-size-base);
    color: var(--color-secondary);
    line-height: 1.6;
}

.auth__form {
    display: grid;
    gap: var(--common-gap);
}

.auth__form.is-disabled {
    opacity: 0.7;
    pointer-events: none;
}

.auth__hint {
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.auth__alert,
.profile__alert,
.admin__alert {
    padding: var(--size-sm) var(--size-base);
    border: 1px solid transparent;
    background-color: var(--color-primary-transparent);
    color: var(--color-secondary);
    font-size: var(--font-size-sm);
    line-height: 1.5;
}

.auth__alert.is-error,
.profile__alert.is-error,
.admin__alert.is-error,
.auth__alert--error {
    border-color: var(--color-error);
    background-color: var(--color-error-transparent);
    color: var(--color-error);
}

.auth__alert.is-success,
.profile__alert.is-success,
.admin__alert.is-success,
.auth__alert--success {
    border-color: var(--color-accent);
    background-color: var(--color-accent-transparent);
    color: var(--color-text-accent);
}

.auth__alert.is-info,
.profile__alert.is-info,
.admin__alert.is-info,
.auth__alert--info {
    border-color: var(--color-primary);
    background-color: var(--color-primary-transparent);
    color: var(--color-primary);
}

.profile-card {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: var(--common-gap);
    height: 100%;
}

.profile-card__header {
    display: grid;
    gap: var(--size-xs);
}

.profile-card__title {
    font-size: clamp(1.5rem, 3vw, 1.9rem);
    font-weight: 600;
}

.profile-card__description {
    font-size: var(--font-size-base);
    color: var(--color-secondary);
}

.profile-form {
    display: grid;
    gap: var(--common-gap);
}

.profile-form.is-disabled {
    opacity: 0.7;
    pointer-events: none;
}

.profile-card--courses .profile-courses {
    display: grid;
    gap: var(--size-sm);
}

.profile-courses__empty {
    margin: 0;
    color: var(--color-secondary);
}

.profile-courses__list {
    display: grid;
    gap: var(--common-gap);
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    list-style: none;
    margin: 0;
    padding: 0;
}

.profile-courses__item {
    list-style: none;
}

.profile-course {
    color: inherit;
    text-decoration: none;
}

.profile-course:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 4px;
}

.profile-course:not(.profile-course--link) {
    cursor: default;
}

.profile-courses__item:hover .profile-course__title {
    color: var(--color-primary);
}

.profile-course__media {
    margin: 0;
}

.profile-course__title {
    margin: 0;
}

.profile-course__description {
    margin: 0;
}

.profile-course__meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--size-xs);
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.profile-course__meta-item {
    display: flex;
    gap: var(--size-sm);
    align-items: center;
}

.course-player {
    display: grid;
    gap: var(--size-max);
}

.course-player__container {
    display: grid;
    gap: var(--size-lg);
    padding-bottom: var(--size-max);
}

.course-player__header {
    min-height: 210px;
    position: relative;
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: center;
}

.course-player__header::before {
    position: absolute;
    content: '';
    left: 0;
    top: 0;
    bottom: 0;
    right: 0;
    background: linear-gradient(90deg, var(--color-page-view-header), var(--color-page-view-header), transparent);
    z-index: 10;
}

.course-player__image-container {
    display: flex;
    justify-content: flex-end;
}

.course-player__figure {
    position: relative;
    right: 0;
    height: 200px;
    width: 200px;
    display: flex;
    align-items: center;
    z-index: 15;
    margin: var(--size-sm) 0;
}

.course-player__image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    user-select: none;
    pointer-events: none;
    border-radius: var(--size-xs);
}

.course-player__header-content {
    position: absolute;
    display: grid;
    gap: var(--size-sm);
    z-index: 20;
}

.course-player__header-content * {
    color: var(--color-page-view-header-opposite) !important;
}

.course-player__title {
    margin: 0;
    font-size: clamp(2.25rem, 5vw, 3rem);
    font-weight: 700;
}

.course-player__description {
    margin: 0;
    font-size: var(--font-size-lg);
    color: var(--color-secondary);
    line-height: 1.6;
}

@media (max-width: 600px) {
    .course-player__header {
        flex-direction: column;
        padding-block: var(--page-side-padding);
        gap: var(--size-base);
    }

    .course-player__figure {
        width: 100%; 
        margin: 0;
    }

    .course-player__header-content {
        position: relative;
    }
}

.course-player__meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--size-sm);
    margin: 0;
    padding: 0;
    list-style: none;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__meta-item {
    display: flex;
    gap: var(--size-xs);
    align-items: baseline;
}

.course-player__meta-label {
    font-weight: 600;
}

.course-player__meta-value {
    display: flex;
    gap: var(--size-xs);
    margin: 0;
}

.course-player__stats {
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__layout {
    display: grid;
    gap: var(--common-gap);
    align-items: start;
    grid-template-columns: minmax(260px, 320px) minmax(0, 1fr);
}

.course-player__sidebar {
    display: grid;
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
    position: sticky;
    top: calc(var(--header-height) + var(--common-gap));
    max-height: 100vh;
    overflow-y: auto;
}

.course-player__sidebar-header {
    display: grid;
    gap: var(--size-xs);
    padding: var(--size-mid);
    border-bottom: 1px solid var(--color-border);
}

.course-player__sidebar-title {
    margin: 0;
    font-size: clamp(1.25rem, 3vw, 1.5rem);
    font-weight: 600;
}

.course-player__sidebar-description {
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__topics {
    display: grid;
    gap: var(--size-base);
    list-style: none;
    margin: 0;
    padding: var(--size-mid) 0;
}

.course-player__topic {
    display: grid;
    gap: var(--size-base);
}

.course-player__topic-title {
    margin: 0;
    font-size: var(--font-size-lg);
    padding: 0 var(--size-mid);
    font-weight: 600;
}

.course-player__topic-description {
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__steps {
    display: grid;
    list-style: none;
    margin: 0;
    padding: 0;
}

.course-player__step {
    list-style: none;
}

.course-player__step--empty {
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__step-button {
    display: flex;
    align-items: center;
    gap: var(--size-sm);
    width: 100%;
    border-block: 1px solid transparent;
    border-inline: none;
    background-color: transparent;
    color: inherit;
    text-align: left;
    cursor: pointer;
    padding: var(--size-sm) var(--size-mid);
}

.course-player__step-button:hover,
.course-player__step-button:focus-visible {
    color: var(--color-primary);
    outline: none;
}

.course-player__step-button.is-active {
    border-color: var(--color-primary);
    background-color: var(--color-primary-transparent);
    color: var(--color-primary);
}

.course-player__step-order {
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__step-content {
    display: grid;
}

.course-player__step-label {
    font-weight: 600;
}

.course-player__step-meta {
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__body {
    display: flex;
    flex-direction: column;
    gap: var(--size-base);
}

.course-player__content {
    display: grid;
    gap: var(--size-mid);
    padding: var(--size-mid);
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
}

.course-player__placeholder {
    margin: 0;
    font-size: var(--font-size-base);
    color: var(--color-secondary);
}

.course-player__error {
    margin: 0;
    padding: var(--size-sm);
    border-radius: var(--size-sm);
    background-color: var(--color-error-transparent);
    color: var(--color-error);
    font-weight: 600;
}

.course-player__content-header {
    display: grid;
    gap: var(--size-xs);
}

.course-player__breadcrumb {
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__lesson-title {
    margin: 0;
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
}

.course-player__lesson-meta {
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__lesson-description {
    margin: 0;
    font-size: var(--font-size-base);
    color: var(--color-secondary);
    line-height: 1.6;
}

.course-player__lesson-content {
    display: flex;
    flex-direction: column;
    gap: var(--size-lg);
}

.course-player__lesson-sections {
    display: flex;
    flex-direction: column;
    gap: var(--size-lg);
}

.course-player__section {
    display: flex;
    flex-direction: column;
    gap: var(--size-base);
}

.course-player__section-title {
    margin-bottom: var(--size-base);
}

.course-player__section > *:last-child {
    margin-bottom: 0 !important;
}

.course-player__media {
    display: grid;
    gap: var(--size-xs);
}

.course-player__resources {
    display: grid;
    gap: var(--size-sm);
    padding: var(--size-base);
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
}

.course-player__resources-title {
    margin: 0;
    font-size: var(--font-size-base);
    font-weight: 600;
}

.course-player__resources-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: var(--size-xs);
}

.course-player__resource-item {
    display: flex;
}

.course-player__resource-link {
    display: inline-flex;
    align-items: center;
    gap: var(--size-xs);
    font-weight: 600;
    font-size: var(--font-size-sm);
    color: var(--color-primary);
}

.course-player__resource-link:hover,
.course-player__resource-link:focus-visible {
    text-decoration: underline;
}

.course-player__resource-extension {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 2.5rem;
    padding: var(--size-xs);
    border-radius: var(--size-xs);
    font-size: var(--font-size-xs);
    font-weight: 600;
    background-color: var(--color-primary-transparent);
    color: var(--color-primary);
}

.course-player__video {
    width: 100%;
    max-height: 560px;
    border-radius: var(--size-sm);
    background-color: #000;
}

.course-player__test {
    display: grid;
    gap: var(--size-mid);
}

.course-player__test-description {
    margin: 0;
    color: var(--color-secondary);
}

.course-player__test-form {
    display: grid;
    gap: var(--size-mid);
}

.course-player__test-timer {
    margin: 0;
    font-weight: 600;
}

.course-player__question-counter {
    margin: 0;
    color: var(--color-secondary);
}

.course-player__test-start {
    display: flex;
    justify-content: center;
}

.course-player__question-step {
    display: grid;
    gap: var(--size-sm);
}

.course-player__feedback {
    margin: 0;
    font-weight: 600;
    text-align: center;
    padding-block: var(--size-base);
}

.course-player__feedback--correct {
    color: var(--color-text-accent);
}

.course-player__feedback--incorrect {
    color: var(--color-error);
}

.course-player__feedback--info {
    background-color: var(--color-bg-top);
    border-color: var(--color-border);
    color: var(--color-secondary);
}

.course-player__questions {
    display: grid;
    gap: var(--size-sm);
    list-style: none;
    margin: 0;
    padding: 0;
}

.course-player__question-section {
    display: flex;
    flex-direction: column;
    gap: var(--size-base);
}

.course-player__question {
    display: grid;
    gap: var(--size-base);
    padding: var(--size-mid);
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
}

.course-player__question-title {
    margin: 0;
    font-size: var(--font-size-lg);
    font-weight: 600;
}

.course-player__answer {
    width: 100%;
    padding: var(--size-sm);
    border: 1px solid var(--color-border);
    font: inherit;
    resize: none;
}

.course-player__options {
    display: grid;
    gap: var(--size-xs);
    list-style: none;
    margin: 0;
    padding: 0;
}

.course-player__test-form [hidden] {
    display: none !important;
}

.course-player__option-label {
    display: flex;
    gap: var(--size-sm);
    align-items: center;
    font-size: var(--font-size-base);
}

.course-player__option-text {
    flex: 1;
}

.course-player__actions {
    display: flex;
    gap: var(--size-sm);
    flex-wrap: wrap;
    justify-content: flex-end;
}

.course-player__submit {
    min-width: 200px;
}

.course-player__test-error {
    margin: 0;
    padding: var(--size-sm);
    border-radius: var(--size-sm);
    background-color: var(--color-error-transparent);
    color: var(--color-error);
}

.course-player__test-result {
    display: grid;
    gap: var(--size-sm);
}

.course-player__test-summary {
    margin: 0;
    font-weight: 600;
}

.course-player__test-answers {
    display: grid;
    gap: var(--size-sm);
    list-style: none;
    margin: 0;
    padding: 0;
}

.course-player__test-answer {
    display: grid;
    gap: var(--size-xs);
    padding: var(--size-base);
    border: 1px solid transparent;
}

.course-player__test-answer--correct {
    background-color: var(--color-accent-transparent);
    color: var(--color-text-accent);
    border: 1px solid var(--color-accent);
}

.course-player__test-answer--incorrect {
    background-color: var(--color-error-transparent);
    color: var(--color-error);
    border: 1px solid var(--color-error);
}

.course-player__test-answer-title {
    margin: 0;
    font-weight: 600;
}

.course-player__test-answer-status {
    margin: 0;
    font-size: var(--font-size-sm);
}

.course-player__test-answer-detail {
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-player__test-answer-explanation {
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
    padding-top: var(--size-base);
}

.course-player__empty {
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

@media (max-width: 1024px) {
    .course-player__layout {
        display: flex;
        flex-direction: column-reverse;
        gap: var(--common-gap);
    }

    .course-player__content {
        width: 100%;
    }

    .course-player__sidebar {
        width: 100%;
        max-height: none;
    }
}

@media (max-width: 768px) {
    .course-player__header-content {
        gap: var(--size-sm);
    }
}


.category-page {
    display: grid;
    gap: var(--size-max);
}

.category-page__header {
    display: grid;
    gap: var(--size-xs);
}

.category-page__title {
    font-size: clamp(2rem, 4vw, 2.5rem);
    font-weight: 700;
}

.category-page__description {
    font-size: var(--font-size-lg);
    color: var(--color-secondary);
    line-height: 1.6;
}

.error {
    display: grid;
    justify-items: center;
    gap: var(--common-gap);
    text-align: center;
}

.error__code {
    font-size: clamp(4rem, 12vw, 6rem);
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.05em;
}

.error__icon {
    font-size: clamp(3rem, 10vw, 4rem);
}

.error__title {
    font-size: clamp(2rem, 5vw, 2.75rem);
    font-weight: 700;
}

.error__message {
    max-width: 520px;
    font-size: var(--font-size-lg);
    color: var(--color-secondary);
    line-height: 1.6;
}

.error__actions {
    display: flex;
    gap: var(--common-gap);
    flex-wrap: wrap;
    justify-content: center;
}

.home {
    display: grid;
    gap: var(--size-max);
}

.home__header {
    text-align: center;
    display: grid;
    gap: var(--size-sm);
}

.home__title {
    font-size: clamp(2.5rem, 6vw, 3.5rem);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.home__subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-secondary);
}

.blog__title {
    font-size: clamp(1.75rem, 4vw, 2.25rem);
    font-weight: 600;
}

.blog__posts {
    display: grid;
    gap: var(--common-gap);
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
}

.blog__empty {
    color: var(--color-secondary);
    font-size: var(--font-size-base);
}

.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--size-xs);
    margin-block: var(--size-sm);
    list-style: none;
}

.tag-list__link {
    display: inline-flex;
    align-items: center;
    gap: var(--size-xs);
    background-color: var(--color-primary-transparent);
    padding: var(--size-xs) var(--size-sm);
    border: 1px solid var(--color-border);
    color: var(--color-primary);
    font-size: var(--font-size-sm);
}

.tag-list__link:hover {
    background-color: var(--color-primary);
    color: #ffffff;
    border-color: var(--color-primary);
}

.post-card {
    display: flex;
    flex-direction: column;
    gap: var(--size-base);
    padding: var(--size-base);
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
    user-select: none;
    cursor: pointer;
    overflow: hidden;
}

.post-card:hover {
    border-color: var(--color-primary);
}

.post-card:hover .post-card__link {
    color: var(--color-primary);
}

.post-card__content {
    display: flex;
    flex-direction: column;
    gap: var(--common-gap);
}

.post-card__figure {
    margin: 0;
    height: 200px;
}

.post-card__image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: var(--size-xs);
    pointer-events: none;
}

.post-card__title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    width: 100%;
    white-space: nowrap;
    text-overflow: ellipsis;
    overflow: hidden;
    white-space: nowrap;
}

.post-card__link {
    color: var(--color-text);
}

.post-card__link--static,
.post-card__tag-link--static {
    color: inherit;
    text-decoration: none;
    pointer-events: none;
}

.post-card__description {
    color: var(--color-secondary);
    font-size: var(--font-size-base);
}

.post-card__meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--size-sm);
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.post-card__tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--size-xs);
    list-style: none;
}

.post-card__tag {
    padding: 0.25rem 0.5rem;
    background-color: rgba(16, 185, 129, 0.1);
    font-size: var(--font-size-xs);
    border: 1px solid transparent;
}

.post-card__tag:hover {
    border-color: var(--color-accent);
}

.post-card__tag-link {
    color: var(--color-accent);
}

.post__layout {
    display: grid;
    gap: var(--common-gap);
}

.post-progress {
    position: fixed;
    top: var(--post-progress-offset, 0px);
    left: 0;
    width: 100%;
    height: var(--size-xs);
    background-color: var(--color-border);
    background-color: color-mix(
        in srgb,
        var(--color-primary) 15%,
        transparent
    );
    transform-origin: left center;
    opacity: 0;
    transition: opacity 0.2s ease;
    pointer-events: none;
    z-index: 1200;
}

.post-progress--visible {
    opacity: 1;
}

.post-progress__bar {
    width: 100%;
    height: 100%;
    background-color: var(--color-primary);
    transform: scaleX(0);
    transform-origin: left center;
    transition: transform 0.1s linear;
}

.post-progress--complete .post-progress__bar {
    background-color: var(--color-primary);
}

body.post-image-modal-open .header,
body.post-image-modal-open .post-progress {
    display: none !important;
}

@media (prefers-reduced-motion: reduce) {
    .post-progress,
    .post-progress__bar {
        transition-duration: 0.01ms !important;
        transition-delay: 0ms !important;
    }
}

.post__section :nth-child(2) {
    margin-top: 0 !important;
}
.post__section > *:last-child {
    margin-bottom: 0 !important;
}

.post__section-title {
    margin-bottom: var(--size-base);
}

section[class*="__section--pv-0"] {
    padding-block: 0;
}

section[class*="__section--pv-4"] {
    padding-block: 4px;
}

section[class*="__section--pv-8"] {
    padding-block: 8px;
}

section[class*="__section--pv-16"] {
    padding-block: 16px;
}

section[class*="__section--pv-32"] {
    padding-block: 32px;
}

section[class*="__section--pv-64"] {
    padding-block: 64px;
}

section[class*="__section--pv-128"] {
    padding-block: 128px;
}

section[class*="__section--mv-0"] {
    margin-block: 0;
}

section[class*="__section--mv-4"] {
    margin-block: 4px;
}

section[class*="__section--mv-8"] {
    margin-block: 8px;
}

section[class*="__section--mv-16"] {
    margin-block: 16px;
}

section[class*="__section--mv-32"] {
    margin-block: 32px;
}

section[class*="__section--mv-64"] {
    margin-block: 64px;
}

section[class*="__section--mv-128"] {
    margin-block: 128px;
}

.post__header {
    display: grid;
    padding: var(--size-mid);
    border: 1px solid var(--color-border);
    position: relative;
    overflow: hidden;
    background-color: var(--color-bg-top);
}

.post__header > * {
    position: relative;
    z-index: 1;
}

.post__image-wrapper {
    overflow: hidden;
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
}

.post__image-wrapper img {
    max-height: 200px;
    object-fit: cover;
}

.post__image {
    width: 100%;
    display: block;
    border: 1px solid var(--color-border);
}

.post__title {
    font-size: clamp(2rem, 5vw, 2.5rem);
    font-weight: 900;
    margin-top: var(--size-base);
}

.post__description {
    font-size: var(--font-size-base);
    color: var(--color-secondary);
}

.post__meta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--size-sm);
    padding: var(--size-sm);
    border: 1px solid var(--color-border);
    background-color: var(--color-primary-transparent);
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
    margin-top: var(--size-mid);
}

.post__meta-item {
    display: inline-flex;
    align-items: center;
    gap: var(--size-sm);
    padding: var(--size-sm);
    color: var(--color-text);
}

.post__sidebar {
    display: grid;
    gap: var(--common-gap);
    overflow-x: hidden;
    white-space: nowrap;
    text-overflow: ellipsis;
}

.post__sidebar a {
    color: var(--color-secondary);
    font-size: var(--font-size-sm);
}

.post__sidebar a:hover,
.post__sidebar a:focus-visible {
    color: var(--color-primary);
}

.post__sidebar h2 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--size-base);
}

.ad-slot {
    height: auto;
    width: 100%;
    background-color: var(--color-bg-top);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-secondary);
    font-size: var(--font-size-sm);
    text-align: center;
    position: relative;
}

.ad-slot::before {
    content: 'Advertisement';
    display: block;
    position: absolute;
    font-size: var(--font-size-xs);
    color: var(--color-secondary);
}

.adsbygoogle {
    display: block;
    width: 100%;
    height: 100%;
}

.adsbygoogle * {
    width: 100% !important;
    height: auto;
}

.post__share {
    display: grid;
    gap: var(--size-sm);
    padding: var(--size-mid);
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
}

.post__share-title {
    margin: 0;
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text);
}

.post__share-button {
    display: inline-flex;
    align-items: center;
    gap: var(--size-sm);
    padding: var(--size-sm);
    border: 1px dashed var(--color-border);
    background-color: transparent;
    font-weight: 600;
    font-size: var(--font-size-sm);
    cursor: pointer;
}

.post__share-button:hover,
.post__share-button:focus-visible {
    background-color: var(--color-primary-transparent);
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.post__share-button:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

.post__share-button-icon {
    font-size: var(--font-size-sm);
    line-height: 1;
}

.post__share-feedback {
    margin: 0;
    font-size: var(--font-size-xs);
    color: var(--color-secondary);
}

.post__share-feedback--error {
    color: var(--color-error);
}

.post__toc {
    overflow: hidden;
    border: 1px solid var(--color-border);
    padding: var(--size-mid);
    background-color: var(--color-bg-top);
}

.post__toc-list {
    display: flex;
    flex-direction: column;
    gap: var(--size-xs);
}

.post__toc-item {
    display: flex;
    align-items: center;
}

.post__toc-item::before {
    content: '•';
    display: inline-block;
    margin-right: 0.5rem;
    color: var(--color-secondary);
    font-size: var(--font-size-sm);
    line-height: 1;
}

.post__toc-link {
    display: block;
    width: 100%;
    overflow: hidden;
    white-space: nowrap;
    text-overflow: ellipsis;
} 
.post__related {
    display: grid;
    gap: var(--common-gap);
}

.post__related-title {
    font-size: clamp(1.5rem, 3vw, 1.9rem);
    font-weight: 600;
}

.post__related-grid {
    display: flex;
    overflow-x: auto;
    flex-wrap: nowrap;
    gap: var(--size-sm);
}

.post__related-card {
    overflow: hidden;
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
    display: inline-grid;
    gap: 0;
    flex: 0 0 min(100%, 20rem);
    width: min(100%, 20rem);
    margin-bottom: var(--size-sm);
    color: var(--color-text);
    text-decoration: none;
}

.post__related-card * {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.post__related-image {
    width: 100%;
    height: 180px;
    object-fit: cover;
}

.post__related-content {
    padding: var(--size-base);
    display: grid;
    gap: var(--size-xs);
}

.post__related-heading {
    font-size: clamp(1.05rem, 2.8vw, 1.2rem);
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.post__related-link {
    color: var(--color-text);
    font-weight: 600;
}

.post__related-card:hover,
.post__related-card:focus-visible {
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.post__related-date {
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

@media (min-width: 1024px) {
    .post__layout {
        grid-template-columns: 1fr 2fr;
        align-items: start;
    }

    .post__header {
        grid-column: 1 / -1;
    }

    .post__content {
        grid-column: 2;
    }

    .post__sidebar {
        grid-column: 1;
        grid-row: 2;
        position: sticky;
        top: calc(var(--header-height) + var(--common-gap));
    }
}

@media (max-width: 768px) {
    .post__meta {
        flex-direction: column;
        align-items: flex-start;
    }

    .post__meta-item {
        width: 100%;
    }
}

.comments__container {
    display: grid;
    gap: var(--common-gap);
    padding: var(--size-mid);
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
    width: 100%;
}

.comments__header-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--common-gap);
}

.comments__title {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 600;
}

.comments__count {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 2.25rem;
    padding: 0.25rem 0.75rem;
    background-color: color-mix(in srgb, var(--color-primary) 12%, transparent);
    color: var(--color-primary);
    font-weight: 600;
    border-radius: 999px;
}

.comments__alert {
    padding: 0.75rem 1rem;
    border: 1px solid color-mix(in srgb, var(--color-border) 70%, transparent);
    background-color: color-mix(in srgb, var(--color-accent) 8%, transparent);
    color: color-mix(
        in srgb,
        var(--color-text) 80%,
        var(--color-secondary) 20%
    );
}

.comments__alert[hidden] {
    display: none !important;
}

.comments__form {
    display: grid;
    gap: var(--size-sm);
    padding: var(--size-base);
    border: 1px solid color-mix(in srgb, var(--color-border) 70%, transparent);
    background-color: color-mix(in srgb, var(--color-primary) 6%, transparent);
}

.comments__reply-context {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--size-sm);
    padding: 0.5rem 0.75rem;
    background-color: color-mix(in srgb, var(--color-border) 60%, transparent);
    font-size: var(--font-size-sm);
}

.comments__reply-context[hidden] {
    display: none !important;
}

.comments__cancel-reply {
    padding: 0.25rem 0.6rem;
    border: 1px solid transparent;
    background-color: color-mix(in srgb, var(--color-error) 12%, transparent);
    color: var(--color-error);
    font-size: var(--font-size-sm);
}

.comments__cancel-reply:hover,
.comments__cancel-reply:focus-visible {
    border-color: var(--color-error);
}

.comments__label {
    font-weight: 600;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.comments__textarea {
    width: 100%;
    min-height: 140px;
    padding: 1rem 1.25rem;
    border: 1px solid color-mix(in srgb, var(--color-border) 70%, transparent);
    background-color: var(--color-bg-top);
    color: var(--color-text);
    font-size: var(--font-size-base);
    line-height: 1.6;
}

.comments__textarea:focus-visible {
    outline: none;
    border-color: var(--color-primary);
}

.comments__submit {
    justify-self: flex-end;
    padding: 0.65rem 1.5rem;
    border: 1px solid transparent;
    background-color: var(--color-primary);
    color: var(--color-text-darker);
    font-weight: 600;
}

.comments__submit:hover,
.comments__submit:focus-visible {
    background-color: var(--color-primary-hover);
}

.comments__sign-in {
    font-size: var(--font-size-base);
    color: var(--color-secondary);
}

.comments__sign-in a {
    color: var(--color-primary);
    font-weight: 600;
}

.comments__sign-in a:hover,
.comments__sign-in a:focus-visible {
    text-decoration: underline;
}

.comments__empty {
    font-style: italic;
    color: var(--color-secondary);
}

.comments__list {
    display: grid;
    gap: var(--common-gap);
}

.comments__item {
    display: grid;
    gap: var(--size-sm);
}

.comments__card {
    display: flex;
    flex-direction: column;
    gap: var(--size-sm);
    padding: var(--size-base);
    border: 1px solid var(--color-border);
    background-color: color-mix(in srgb, var(--color-bg-top) 98%, transparent);
}

.comments__header {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    justify-content: space-between;
    gap: var(--size-xs);
}

.comments__author {
    font-weight: 600;
    color: var(--color-text);
}

.comments__time {
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.comments__content {
    line-height: 1.6;
    color: var(--color-text);
    white-space: pre-line;
}

.comments__actions {
    display: flex;
    flex-wrap: wrap;
    gap: var(--size-sm);
}

.comments__actions button {
    padding: 0.35rem 0.85rem;
    border: 1px solid var(--color-border);
    background-color: color-mix(in srgb, var(--color-border) 35%, transparent);
    color: var(--color-secondary);
    font-size: var(--font-size-sm);
}

.comments__actions button:hover,
.comments__actions button:focus-visible {
    background-color: var(--color-primary);
    color: var(--color-text-darker);
}

.comments__delete-button {
    background-color: color-mix(in srgb, var(--color-error) 12%, transparent);
    color: var(--color-error);
    border-color: color-mix(in srgb, var(--color-error) 40%, transparent);
}

.comments__delete-button:hover,
.comments__delete-button:focus-visible {
    background-color: color-mix(in srgb, var(--color-error) 25%, transparent);
    color: var(--color-text-darker);
}

.comments__replies {
    display: grid;
    gap: var(--size-sm);
    border-left: 2px solid var(--color-primary);
    padding-left: var(--size-base);
}

@media (max-width: 640px) {
    .post__sidebar > *,
    .post__content,
    .comments__container,
    .comments__card {
        padding: var(--page-side-padding) !important;
    }

    .comments__replies {
        border-left: none;
        padding-left: 0;
    }
}

.pagination {
    display: flex;
    justify-content: center;
}

.pagination__list {
    display: flex;
    align-items: center;
    gap: var(--size-sm);
    font-size: var(--font-size-sm);
}

.pagination__button {
    padding: 0.35rem 0.85rem;
    border: 1px solid var(--color-border);
    background-color: var(--color-bg-top);
    color: var(--color-text);
}

.pagination__button:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    background-color: rgba(59, 130, 246, 0.08);
}

.pagination__info {
    color: var(--color-secondary);
}

.footer {
    grid-area: footer;
    background-color: var(--color-bg-top-darker);
}

.footer__container {
    display: grid;
    gap: var(--size-mid);
}

.footer__info {
    display: grid;
    gap: var(--size-xs);
}

.footer__brand-link {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--color-text-darker);
}

.footer__brand-link:hover {
    color: var(--color-primary);
}

.footer__text {
    color: var(--color-secondary-darker);
    font-size: var(--font-size-base);
}

.footer__nav {
    display: grid;
    gap: var(--size-mid);
}

.footer__social {
    display: flex;
    flex-direction: column;
    gap: var(--common-gap);
}
.footer__social-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--size-sm);
    margin: 0;
    padding: 0;
    list-style: none;
}
.footer__social-item {
    flex: 0 0 auto;
}
.footer__social-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.75rem;
    height: 2.75rem;
    border-radius: 50%;
    position: relative;
    color: inherit;
}
.footer__social-link:hover,
.footer__social-link:focus-visible {
    background-color: color-mix(in srgb, var(--color-primary) 10%, rgba(255, 255, 255, 0.1));
}
.footer__social-icon {
    width: 1.75rem;
    height: 1.75rem;
    object-fit: contain;
}
.footer__social-label {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
    white-space: nowrap;
}
.footer__social-fallback {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
    font-weight: 600;
    font-size: 0.85rem;
    text-align: center;
    padding: 0 0.5rem;
    color: var(--color-text-darker);
}

.footer__group {
    display: flex;
    flex-direction: column;
    gap: var(--size-xs);
}

.footer__heading {
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-darker);
    margin-bottom: var(--size-sm);
}

.footer__list {
    display: grid;
    gap: var(--size-xs);
    list-style: none;
}

.footer__link {
    font-size: var(--font-size-base);
    color: var(--color-secondary-darker);
}

.footer__link:hover {
    color: var(--color-primary);
}

.footer__bottom {
    margin-top: var(--size-mid);
    padding-top: var(--size-sm);
    border-top: 1px solid var(--color-border-darker);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--common-gap);
    font-size: var(--font-size-sm);
}

.footer__copyright {
    color: var(--color-secondary-darker);
}

.blog__categories {
    display: flex;
    border-bottom: 1px solid var(--color-border);
    margin-bottom: var(--size-sm);
}

.category-list {
    display: flex;
    list-style: none;
    gap: var(--size-xs);
}

.category-list__link {
    margin: var(--size-sm) 0;
    padding: var(--size-sm) var(--size-base);
    display: flex;
    justify-content: center;
    align-items: center;
    border: 1px solid var(--color-border);
    color: var(--color-secondary);
    font-weight: 600;
    font-size: var(--font-size-sm);
}

.category-list__link:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.post-image-modal {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--modal-outside-bg);
    backdrop-filter: blur(2px);
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s ease-in-out;
}

.post-image-modal--active {
    opacity: 1;
    pointer-events: auto;
}

.post-image-modal__image {
    max-width: min(90vw, 1200px);
    max-height: 90vh;
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.5);
    object-fit: contain;
}

.post-image-modal__nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: var(--size-lg);
    height: var(--size-lg);
    border-radius: 100%;
    border: none;
    color: #ffffff;
    cursor: pointer;
    display: grid;
    place-items: center;
    background-color: transparent;
}

.post-image-modal__nav::before {
    content: "";
    width: 12px;
    height: 12px;
    border-right: 2px solid currentColor;
    border-bottom: 2px solid currentColor;
}

.post-image-modal__nav--prev {
    left: clamp(0.5rem, 4vw, 3rem);
}

.post-image-modal__nav--prev::before {
    transform: rotate(135deg);
}

.post-image-modal__nav--next {
    right: clamp(0.5rem, 4vw, 3rem);
}

.post-image-modal__nav--next::before {
    transform: rotate(-45deg);
}

.post-image-modal__nav:hover,
.post-image-modal__nav:focus-visible {
    outline: none;
}

.post-image-modal__nav[hidden] {
    display: none;
}

.post-image-modal__close {
    position: absolute;
    top: var(--size-base);
    right: var(--size-base);
    width: var(--size-mid);
    height: var(--size-mid);
    border-radius: 100%;
    border: none;
    background-color: transparent;
    color: #ffffff;
    font-size: 0;
    cursor: pointer;
    display: grid;
    place-items: center;
}

.post-image-modal__close::before,
.post-image-modal__close::after {
    content: "";
    position: absolute;
    width: 18px;
    height: 2px;
    background-color: currentColor;
    border-radius: 999px;
}

.post-image-modal__close::before {
    transform: rotate(45deg);
}

.post-image-modal__close::after {
    transform: rotate(-45deg);
}

.post-image-modal__close:hover,
.post-image-modal__close:focus {
    outline: none;
}

.post-image-modal[hidden] {
    display: none;
}

html.course-modal-open,
body.course-modal-open {
    overflow: hidden;
}

.course-modal {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--modal-outside-bg);
    backdrop-filter: blur(3px);
    z-index: 1100;
    opacity: 0;
    pointer-events: none;
}

.course-modal--active {
    opacity: 1;
    pointer-events: auto;
}

.course-modal[hidden] {
    display: none;
}

.course-modal__dialog {
    position: relative;
    width: min(840px, 100%);
    max-height: min(90vh, 720px);
    overflow: hidden auto;
    background-color: var(--color-bg-top);
    color: var(--color-text);
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.45);
    padding: clamp(1.5rem, 4vw, 2.5rem);
    margin-inline: var(--size-base);
    outline: none;
}

.course-modal__content {
    display: grid;
    gap: var(--size-mid);
}

.course-modal__media {
    height: 100%;
}

@media (min-width: 768px) {
    .course-modal__content {
        grid-template-columns: minmax(0, 1fr) minmax(0, 1.25fr);
        align-items: start;
    }
}

@media (max-width: 768px) {
    .course-modal__media {
        height: 200px;
    }
}

@media (max-width: 500px) {
    .course-modal__actions {
        flex-direction: column;
    }
}

.course-modal__details {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    height: 100%;
}

.course-modal__media[hidden] {
    display: none;
}

.course-modal__image {
    width: 100%;
    height: 100%;
    border-radius: var(--size-sm);
    object-fit: cover;
}

.course-modal__title {
    font-size: clamp(1.5rem, 2.5vw, 2.25rem);
    line-height: 1.2;
}

.course-modal__price {
    margin-top: var(--size-sm);
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--color-accent);
}

.course-modal__price[hidden] {
    display: none;
}

.course-modal__description {
    margin-top: var(--size-base);
    font-size: var(--font-size-base);
    line-height: 1.6;
}

.course-modal__description[hidden] {
    display: none;
}

.course-modal__topics-wrapper {
    margin-top: var(--size-base);
}

.course-modal__topics-wrapper[hidden] {
    display: none;
}

.course-modal__topics-title {
    font-size: var(--font-size-lg);
    margin-bottom: var(--size-sm);
}

.course-modal__meta {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: var(--size-xs);
    padding: 0;
    margin: var(--size-sm) 0 0;
}

.course-modal__meta[hidden] {
    display: none;
}

.course-modal__meta-item {
    background-color: color-mix(in srgb, var(--color-accent) 12%, transparent);
    color: var(--color-text-accent);
    padding: var(--size-xs) var(--size-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.course-modal__topics-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--size-sm);
    padding: 0;
    margin: 0;
}

.course-modal__topics-item {
    background-color: color-mix(in srgb, var(--color-accent) 8%, transparent);
    color: var(--color-text);
    border-radius: var(--radius-md);
    padding: var(--size-sm) var(--size-base);
    display: flex;
    flex-direction: column;
    gap: var(--size-xs);
}

.course-modal__topic-title {
    margin: 0;
    font-size: var(--font-size-lg);
    font-weight: 600;
}

.course-modal__topic-meta {
    margin: 0;
    font-size: var(--font-size-sm);
    color: var(--color-secondary);
}

.course-modal__topic-description {
    margin: 0;
    font-size: var(--font-size-sm);
    line-height: 1.6;
}

.course-modal__lessons-list {
    list-style: none;
    padding: 0;
    margin: var(--size-xs) 0 0;
    display: flex;
    flex-direction: column;
    gap: var(--size-xs);
}

.course-modal__lesson-item {
    display: flex;
    justify-content: space-between;
    gap: var(--size-sm);
    font-size: var(--font-size-sm);
}

.course-modal__lesson-title {
    font-weight: 500;
}

.course-modal__lesson-duration {
    color: var(--color-secondary);
    white-space: nowrap;
}

.course-modal__actions {
    margin-top: var(--size-base);
    display: flex;
    justify-content: flex-end;
    flex-wrap: wrap;
    gap: var(--size-sm);
}

.course-modal__cancel {
    border: 1px solid var(--color-border);
    background: transparent;
    color: var(--color-secondary);
    font-size: var(--font-size-base);
    font-weight: 600;
    padding: var(--size-sm) var(--size-lg);
    cursor: pointer;
}

.course-modal__cancel:hover,
.course-modal__cancel:focus-visible {
    color: var(--color-primary);
    border-color: var(--color-primary);
    outline: none;
}

.course-modal__error {
    margin-top: var(--size-sm);
    color: var(--color-error);
    font-size: var(--font-size-sm);
}

.course-modal__purchase {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--size-sm) var(--size-lg);
    background: var(--color-primary);
    color: var(--color-primary-opposite);
    border: none;
    font-size: var(--font-size-base);
    font-weight: 600;
}

.course-modal__purchase:disabled,
.course-modal__purchase[aria-busy="true"] {
    opacity: 0.65;
    cursor: not-allowed;
}

.course-modal__purchase:hover,
.course-modal__purchase:focus-visible {
    background: var(--color-primary-hover);
    outline: none;
}

.page-view {
    display: grid;
}

.page-view__header, .footer, .post {
    padding-block: var(--size-lg);
}

.page-view__header, .footer {
    background-color: var(--color-page-view-header);
}

.comments {
    margin-top: var(--common-gap);
}

.tag-page {
    padding-block: var(--size-max);
}

.tag-page__header {
    margin-bottom: var(--size-mid);
}

.header > *,
.page-view__header > *,
.page-view__section-container,
.footer > *,
.post > *:not(.post-progress),
.comments,
.search > *,
.course-player__header > *:not(.course-player__figure),
.course-player__layout,
.course-player__header-content,
.tag-page__container {
    max-width: var(--page-max-width);
    padding-inline: var(--page-side-padding);
    margin-inline: auto;
    width: 100%;
}

.page-view__title, .page-view__description {
    color: var(--color-page-view-header-opposite);
}

@media (min-width: 768px) {
    .footer__nav {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
}

@media (max-width: 640px) {
    body > header {
        position: static;
    }

    .post-card__image {
        height: 180px;
    }

    .post-card__meta {
        flex-direction: column;
        align-items: flex-start;
    }

    .footer__bottom {
        flex-direction: column;
        align-items: flex-start;
    }

    .footer__social-list {
        justify-content: flex-start;
    }

    .post__content, .post__header {
        padding: var(--size-base);
    }
}

@media (max-width: 520px) {
    .main-content > *, 
    .comments > *,
    .post__layout > *,
    .post__content > *, 
    .blog__posts > *, 
    .search__posts > *,
    .profile__grid > *,
    .post__sidebar > *,
    .post__content,
    .auth__container,
    .search__container {
        border-inline: none !important;
    }

    .search__results > *:first-child {
        padding-inline: var(--page-side-padding);
    }

    .post__layout,
    .comments,
    .search > * {
        padding-inline: 0 !important;
    }

    img.page-view__section-img {
        border-radius: 0;
    }
}