/* Teor.Min — Physics Design System */

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 88px;
}

:target {
    animation: highlight 2s ease-in-out;
}

@keyframes highlight {
    0%   { background-color: var(--highlight-start); }
    50%  { background-color: var(--highlight-mid); }
    100% { background-color: transparent; }
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--background-color);
    color: var(--text-color-primary);
    line-height: 1.6;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
    -webkit-font-smoothing: antialiased;
    font-size: 16px;
    letter-spacing: -0.01em;
    overflow-x: hidden;
    position: relative;
}

/* ─── Three.js фон по бокам ─── */
#physics-bg {
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    overflow: hidden;
}

#physics-bg canvas {
    display: block;
    width: 100% !important;
    height: 100% !important;
}

#physics-bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 55% 70% at 50% 45%, var(--background-color) 0%, transparent 72%);
    pointer-events: none;
}

.physics-bg--mobile::after {
    background: radial-gradient(ellipse 90% 60% at 50% 40%, var(--background-color) 0%, transparent 65%);
}

/* Layout wrappers */
.header,
.main-content,
.container,
.home-button,
.theme-toggle {
    position: relative;
    z-index: 1;
}

.content {
    max-width: 100%;
    overflow-x: auto;
    padding: 20px;
}

.content h2, .content h3, .content h4 {
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.content p {
    max-width: 100%;
    overflow-x: auto;
}

mjx-container {
    max-width: 100% !important;
    overflow-x: auto !important;
    overflow-y: hidden !important;
}

/* ─── Header ─── */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--header-bg);
    backdrop-filter: blur(16px) saturate(1.4);
    -webkit-backdrop-filter: blur(16px) saturate(1.4);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all var(--transition);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    position: relative;
}

.nav {
    display: flex;
    align-items: center;
    gap: 4px;
}

.nav-link {
    text-decoration: none;
    color: var(--text-color-secondary);
    padding: 8px 14px;
    font-weight: 500;
    font-size: 0.9rem;
    border-radius: 8px;
    transition: all var(--transition);
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
    background: var(--primary-subtle);
}

.header-actions {
    position: absolute;
    right: 24px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.mobile-nav-toggle {
    display: none;
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    width: 40px;
    height: 40px;
    cursor: pointer;
    align-items: center;
    justify-content: center;
    color: var(--text-color-primary);
}

.mobile-nav-toggle svg {
    width: 20px;
    height: 20px;
}

/* ─── Main ─── */
.main-content {
    padding-top: 56px;
    min-height: 100vh;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 48px 24px 80px;
    position: relative;
    z-index: 1;
}

/* ─── Hero ─── */
.hero {
    text-align: center;
    margin-bottom: 40px;
}

.hero-title {
    font-size: clamp(1.875rem, 4vw, 2.75rem);
    font-weight: 600;
    color: var(--text-color-primary);
    margin-bottom: 12px;
    letter-spacing: -0.03em;
    line-height: 1.15;
}

.hero-subtitle {
    font-size: 1.0625rem;
    color: var(--text-color-secondary);
    font-weight: 400;
    max-width: 480px;
    margin: 0 auto;
    line-height: 1.5;
}

/* ─── Search ─── */
.search-section {
    margin-bottom: 48px;
}

.search-container {
    position: relative;
    max-width: 640px;
    margin: 0 auto;
}

.search-label {
    display: block;
    text-align: center;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-color-secondary);
    margin-bottom: 12px;
}

.search-input-wrapper {
    position: relative;
}

.search-input {
    width: 100%;
    padding: 16px 20px 16px 52px;
    border: 1.5px solid var(--border-color);
    border-radius: 14px;
    font-size: 1rem;
    font-family: inherit;
    background: var(--card-bg);
    color: var(--text-color-primary);
    transition: all var(--transition);
    box-shadow: var(--shadow-sm);
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px var(--focus-ring), var(--shadow-md);
}

.search-input::placeholder {
    color: var(--text-color-muted);
}

.search-icon-left {
    position: absolute;
    left: 18px;
    top: 50%;
    transform: translateY(-50%);
    width: 20px;
    height: 20px;
    stroke: var(--text-color-muted);
    pointer-events: none;
}

.search-kbd {
    position: absolute;
    right: 14px;
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    align-items: center;
    gap: 4px;
    pointer-events: none;
}

.search-kbd kbd {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 24px;
    height: 24px;
    padding: 0 6px;
    background: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-family: inherit;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-color-muted);
    box-shadow: 0 1px 0 var(--border-color);
}

.search-results {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    right: 0;
    background: var(--card-bg);
    border: 1.5px solid var(--border-color);
    border-radius: 14px;
    box-shadow: var(--shadow-lg);
    max-height: 420px;
    overflow-y: auto;
    z-index: 1000;
    display: none;
}

.search-result-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 18px;
    text-decoration: none;
    color: var(--text-color-primary);
    border-bottom: 1px solid var(--border-color);
    transition: all var(--transition);
}

.search-result-item:last-child {
    border-bottom: none;
}

.search-result-item:hover,
.search-result-item.active {
    background: var(--primary-subtle);
}

.result-icon {
    width: 38px;
    height: 38px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-subtle);
    border-radius: 10px;
}

.result-icon svg {
    width: 20px;
    height: 20px;
    stroke: var(--primary-color);
}

.result-content { flex: 1; min-width: 0; }

.result-title {
    font-size: 0.9375rem;
    font-weight: 500;
    margin-bottom: 3px;
    line-height: 1.35;
}

.result-title mark {
    background: var(--highlight-mark);
    color: var(--primary-color);
    font-weight: 600;
    padding: 1px 3px;
    border-radius: 3px;
}

.result-meta {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8125rem;
    color: var(--text-color-secondary);
}

.result-class {
    font-weight: 600;
    color: var(--primary-color);
}

.result-separator { color: var(--text-color-muted); }

.result-arrow {
    width: 16px;
    height: 16px;
    stroke: var(--text-color-muted);
    flex-shrink: 0;
    transition: transform var(--transition);
}

.search-result-item:hover .result-arrow,
.search-result-item.active .result-arrow {
    stroke: var(--primary-color);
    transform: translateX(3px);
}

.no-search-results {
    text-align: center;
    padding: 32px 20px;
    color: var(--text-color-muted);
    font-size: 0.9375rem;
}

.more-results {
    text-align: center;
    padding: 10px 18px;
    font-size: 0.8125rem;
    color: var(--text-color-secondary);
    background: var(--background-color);
}

/* ─── Courses ─── */
.courses-section {
    margin-top: 16px;
}

.section-header {
    text-align: center;
    margin-bottom: 28px;
}

.section-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-color-primary);
    margin-bottom: 8px;
    letter-spacing: -0.02em;
}

.section-desc {
    font-size: 0.9375rem;
    color: var(--text-color-secondary);
}

.class-tabs {
    display: flex;
    justify-content: center;
    gap: 6px;
    margin-bottom: 32px;
    flex-wrap: wrap;
    padding: 4px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    max-width: 480px;
    margin-left: auto;
    margin-right: auto;
}

.class-tab {
    flex: 1;
    min-width: 0;
    padding: 10px 16px;
    border: none;
    background: transparent;
    border-radius: 8px;
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-color-secondary);
    cursor: pointer;
    transition: all var(--transition);
    white-space: nowrap;
}

.class-tab:hover {
    color: var(--text-color-primary);
    background: var(--background-color);
}

.class-tab.active {
    background: var(--primary-color);
    color: #fff;
}

.class-groups {
    display: flex;
    flex-direction: column;
    gap: 28px;
}

.class-group {
    transition: opacity 0.25s ease, transform 0.25s ease;
}

.class-group.hidden {
    display: none;
}

.class-group-header {
    margin-bottom: 12px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
}

.class-group-title {
    font-size: 1.0625rem;
    font-weight: 600;
    color: var(--text-color-primary);
    margin-bottom: 2px;
}

.class-group-meta {
    font-size: 0.8125rem;
    color: var(--text-color-muted);
}

.semester-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 12px;
}

.semester-card {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 18px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    text-decoration: none;
    color: inherit;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.semester-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-sm);
}

.semester-card-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.semester-label {
    font-weight: 600;
    font-size: 1rem;
    color: var(--text-color-primary);
}

.semester-arrow {
    width: 18px;
    height: 18px;
    stroke: var(--text-color-muted);
    transition: all var(--transition);
}

.semester-card:hover .semester-arrow {
    stroke: var(--primary-color);
    transform: translateX(4px);
}

.semester-desc {
    font-size: 0.8125rem;
    color: var(--text-color-secondary);
    line-height: 1.45;
}

.semester-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 4px;
}

.semester-tag {
    font-size: 0.75rem;
    padding: 3px 8px;
    background: var(--primary-subtle);
    color: var(--primary-color);
    border-radius: 100px;
    font-weight: 500;
}

/* Legacy card grid (backwards compat) */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 12px;
    margin-bottom: 24px;
}

.card {
    display: flex;
    align-items: center;
    gap: 14px;
    background: var(--card-bg);
    border: 1.5px solid var(--border-color);
    border-radius: 14px;
    padding: 20px;
    text-decoration: none;
    transition: all var(--transition);
}

.card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-sm);
}

.card-number {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    background: var(--primary-subtle);
    border-radius: 12px;
    flex-shrink: 0;
}

.card-content { flex: 1; }

.card-title {
    font-weight: 600;
    font-size: 1rem;
    color: var(--text-color-primary);
    margin-bottom: 2px;
}

.card-subtitle {
    font-size: 0.875rem;
    color: var(--text-color-secondary);
}

.card-arrow {
    width: 18px;
    height: 18px;
    stroke: var(--text-color-muted);
    transition: all var(--transition);
}

.card:hover .card-arrow {
    stroke: var(--primary-color);
    transform: translateX(4px);
}

.hint-text {
    text-align: center;
    margin-top: 24px;
    color: var(--text-color-muted);
    font-size: 0.875rem;
}

/* ─── Footer ─── */
.site-footer {
    margin-top: 64px;
    padding: 32px 24px;
    text-align: center;
    border-top: 1px solid var(--border-color);
    background: var(--card-bg);
    border-radius: 16px 16px 0 0;
}

.site-footer p {
    font-size: 0.875rem;
    color: var(--text-color-secondary);
    margin: 0;
}

.site-footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.site-footer a:hover {
    text-decoration: underline;
}

/* ─── Home button ─── */
.home-button {
    position: fixed;
    top: 20px;
    left: 20px;
    background: var(--primary-color);
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    box-shadow: var(--shadow-md);
    transition: all var(--transition);
    z-index: 1001;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
}

.home-button::before {
    content: '';
    width: 20px;
    height: 20px;
    background: #fff;
    mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2'%3E%3Cpath d='M3 9l9-7 9 7v11a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2z'/%3E%3Cpolyline points='9 22 9 12 15 12 15 22'/%3E%3C/svg%3E") center/contain no-repeat;
    -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2'%3E%3Cpath d='M3 9l9-7 9 7v11a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2z'/%3E%3Cpolyline points='9 22 9 12 15 12 15 22'/%3E%3C/svg%3E") center/contain no-repeat;
}

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

/* ─── Theme toggle ─── */
.theme-toggle {
    --icon: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2'%3E%3Cpath d='M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z'/%3E%3C/svg%3E");
    flex-shrink: 0;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 0;
    border-radius: 10px;
    cursor: pointer;
    transition: all var(--transition);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* На страницах без шапки: домой слева, тема справа */
body:has(.home-button) .theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1001;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    box-shadow: var(--shadow-md);
}

.theme-toggle::before {
    content: '';
    width: 18px;
    height: 18px;
    background: var(--text-color-secondary);
    mask-image: var(--icon);
    mask-size: contain;
    mask-repeat: no-repeat;
    mask-position: center;
    -webkit-mask-image: var(--icon);
    -webkit-mask-size: contain;
    -webkit-mask-repeat: no-repeat;
    -webkit-mask-position: center;
    transition: all var(--transition);
}

.theme-toggle:hover {
    border-color: var(--primary-color);
    background: var(--primary-subtle);
}

.theme-toggle:hover::before {
    background: var(--primary-color);
}

/* ─── Content pages nav ─── */
.page-nav {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    margin: 28px 0 20px;
    width: 100%;
    max-width: 520px;
    margin-left: auto;
    margin-right: auto;
}

.page-nav-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    text-decoration: none;
    color: var(--text-color-primary);
    background: var(--card-bg);
    padding: 13px 18px;
    font-weight: 500;
    font-size: 0.875rem;
    border-radius: 10px;
    border: 1px solid var(--border-color);
    transition: background-color 0.15s ease, border-color 0.15s ease;
    text-align: center;
    min-height: 46px;
}

.page-nav-btn:hover {
    border-color: var(--text-color-muted);
    background: var(--background-color);
}

.page-nav-btn--test:hover {
    border-color: var(--primary-color);
    background: var(--background-color);
    color: var(--text-color-primary);
}

.container > nav:not(.page-nav) {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin: 28px 0;
    flex-wrap: wrap;
}

.container nav a:not(.nav-link):not(.card):not(.semester-card):not(.search-result-item):not(.page-nav-btn),
nav a:not(.nav-link):not(.card):not(.semester-card):not(.search-result-item):not(.page-nav-btn) {
    display: inline-block;
    text-decoration: none;
    color: var(--text-color-primary);
    background: var(--card-bg);
    padding: 12px 22px;
    font-weight: 500;
    font-size: 0.9rem;
    border-radius: 10px;
    border: 1.5px solid var(--border-color);
    transition: all var(--transition);
}

.container nav a:not(.nav-link):not(.card):not(.semester-card):not(.search-result-item):not(.page-nav-btn):hover,
nav a:not(.nav-link):not(.card):not(.semester-card):not(.search-result-item):not(.page-nav-btn):hover {
    border-color: var(--primary-color);
    background: var(--primary-color);
    color: #fff;
}

/* ─── List pages (подразделы) ─── */
.page-list {
    padding-top: 72px;
    padding-bottom: 48px;
    max-width: 640px;
}

.page-list h1 {
    margin-bottom: 4px;
}

.page-list h2 {
    margin-top: 8px;
    margin-bottom: 0;
    color: var(--text-color-muted);
    font-size: 1rem;
    font-weight: 500;
}

.sections-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
    margin-top: 12px;
    width: 100%;
    counter-reset: topic-section;
}

.section {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
    counter-increment: topic-section;
}

/* Заголовок раздела — ссылка на формулы */
.button-link {
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 12px;
    background: var(--card-bg);
    color: var(--text-color-primary);
    text-decoration: none;
    padding: 14px 16px;
    font-weight: 600;
    font-size: 0.9375rem;
    line-height: 1.35;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 0.15s ease;
}

.button-link::before {
    content: counter(topic-section);
    width: 26px;
    height: 26px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1.5px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-color-muted);
    background: var(--background-color);
}

.button-link::after {
    content: '→';
    font-size: 1rem;
    color: var(--text-color-muted);
    transition: color 0.15s ease;
}

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

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

/* Список формул внутри раздела */
.section ul {
    list-style: none;
    padding: 10px 16px 12px;
    margin: 0;
}

.section ul::before {
    content: 'В этом разделе';
    display: block;
    font-size: 0.6875rem;
    font-weight: 600;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--text-color-muted);
    padding: 4px 0 8px;
}

.section ul li {
    padding: 9px 0;
    color: var(--text-color-secondary);
    font-size: 0.875rem;
    line-height: 1.5;
    border-bottom: 1px solid var(--border-color);
}

.section ul li:last-child {
    border-bottom: none;
    padding-bottom: 4px;
}

.section ul li:first-of-type {
    padding-top: 0;
}

h1 {
    font-size: clamp(1.75rem, 4vw, 2.25rem);
    font-weight: 600;
    text-align: center;
    letter-spacing: -0.03em;
    color: var(--text-color-primary);
    margin-bottom: 8px;
}

h2 {
    font-size: 1.25rem;
    font-weight: 600;
    text-align: center;
    color: var(--text-color-primary);
    margin: 20px 0;
}

/* ─── Contacts ─── */
.subtitle {
    text-align: center;
    font-size: 1rem;
    color: var(--text-color-secondary);
    margin-bottom: 32px;
}

.contacts-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
    max-width: 600px;
    margin: 0 auto 40px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    background: var(--card-bg);
    border: 1.5px solid var(--border-color);
    border-radius: 14px;
    padding: 20px;
    transition: all var(--transition);
}

.contact-item:hover {
    border-color: var(--primary-color);
}

.contact-icon {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-subtle);
    border-radius: 12px;
    flex-shrink: 0;
}

.contact-icon svg {
    width: 22px;
    height: 22px;
    stroke: var(--primary-color);
}

.contact-label {
    font-size: 0.75rem;
    color: var(--text-color-muted);
    margin-bottom: 4px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.contact-link {
    font-size: 0.9375rem;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    word-break: break-all;
}

.contact-link:hover { text-decoration: underline; }

/* ─── Support ─── */
.support-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-color);
    color: #fff;
    text-decoration: none;
    padding: 16px 36px;
    font-weight: 600;
    font-size: 1rem;
    border-radius: 12px;
    transition: all var(--transition);
    box-shadow: var(--shadow-md);
}

.support-button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.support-section {
    display: flex;
    justify-content: center;
    margin: 40px 0;
}

.support-section img {
    max-width: 280px;
    border-radius: 14px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
}

footer {
    margin-top: 48px;
    padding: 24px;
    text-align: center;
    background: var(--card-bg);
    color: var(--text-color-secondary);
    border-radius: 14px;
    border: 1px solid var(--border-color);
}

strong { font-weight: 600; color: var(--text-color-primary); }
p { margin: 0; }
p a { color: var(--primary-color); text-decoration: none; }
p a:hover { text-decoration: underline; }

img {
    max-width: 100%;
    height: auto;
    border-radius: 10px;
    border: 1px solid var(--border-color);
}

/* Legacy buttons */
.buttons {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 10px;
    margin-top: 16px;
}

.button {
    background: var(--primary-color);
    color: #fff;
    padding: 16px 20px;
    border-radius: 10px;
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9rem;
    transition: all var(--transition);
}

.button:hover { filter: brightness(1.1); }

/* ─── Responsive ─── */
@media (max-width: 768px) {
    .header-container { padding: 0 16px; height: 56px; }
    .main-content { padding-top: 56px; }
    .container { padding: 32px 16px 64px; }
    .hero { margin-bottom: 36px; }
    .hero-stats { gap: 20px; }
    .semester-grid { grid-template-columns: 1fr; }
    .class-tabs { max-width: 100%; }
    .home-button { top: 16px; left: 16px; }
    body:has(.home-button) .theme-toggle { top: 16px; right: 16px; }
}

@media (max-width: 600px) {
    .nav {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        background: var(--header-bg);
        backdrop-filter: blur(16px);
        border-bottom: 1px solid var(--border-color);
        padding: 12px 16px;
        gap: 4px;
    }

    .nav.open { display: flex; }

    .nav-link {
        width: 100%;
        padding: 12px 16px;
        text-align: left;
    }

    .mobile-nav-toggle { display: flex; }

    .search-kbd { display: none; }

    .search-input {
        padding: 14px 16px 14px 48px;
        font-size: 16px;
    }

    .hero-title { font-size: 1.75rem; }
    .hero-subtitle { font-size: 1rem; }

    .class-tab { padding: 8px 10px; font-size: 0.8125rem; }

    .home-button,
    body:has(.home-button) .theme-toggle {
        top: auto;
        bottom: 20px;
        width: 50px;
        height: 50px;
        border-radius: 50%;
        box-shadow: var(--shadow-lg);
    }

    .home-button { left: 16px; }
    body:has(.home-button) .theme-toggle { right: 16px; }

    body:has(.home-button) .container {
        padding-bottom: 96px;
    }

    .contact-item {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }

    .page-nav {
        grid-template-columns: 1fr;
        max-width: 100%;
    }

    .page-nav-btn {
        width: 100%;
    }

    .page-list {
        padding-top: 24px;
    }

    .button-link {
        padding: 12px 14px;
        font-size: 0.875rem;
        gap: 10px;
    }

    .section ul li {
        font-size: 0.8125rem;
        padding: 8px 0;
    }

    mjx-container {
        font-size: 85% !important;
        max-width: calc(100vw - 32px) !important;
    }
}