:root {
    --bg: #fafafa;
    --bg-strong: #e4e5f1;
    --surface: rgba(250, 250, 250, 0.9);
    --surface-strong: #fafafa;
    --surface-alt: #d2d3db;
    --ink: #484b6a;
    --ink-soft: #9394a5;
    --line: rgba(72, 75, 106, 0.12);
    --line-strong: rgba(72, 75, 106, 0.22);
    --accent: #6c7ae0;
    --accent-strong: #5563c9;
    --accent-soft: rgba(108, 122, 224, 0.14);
    --warm: #8c92ff;
    --gold: #b2b8ff;
    --danger: #c65f7a;
    --shadow-lg: 0 30px 70px rgba(72, 75, 106, 0.14);
    --shadow-md: 0 18px 40px rgba(72, 75, 106, 0.1);
    --shadow-sm: 0 10px 24px rgba(72, 75, 106, 0.08);
    --radius-xl: 28px;
    --radius-lg: 22px;
    --radius-md: 16px;
    --radius-sm: 12px;
    --body-grad-a: rgba(108, 122, 224, 0.12);
    --body-grad-b: rgba(178, 184, 255, 0.16);
    --body-grad-c1: #fafafa;
    --body-grad-c2: #e4e5f1;
    --body-grad-c3: #d2d3db;
}

* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    min-height: 100%;
}

body {
    font-family: "Manrope", "Segoe UI", sans-serif;
    color: var(--ink);
    background:
        radial-gradient(circle at top left, var(--body-grad-a), transparent 28%),
        radial-gradient(circle at top right, var(--body-grad-b), transparent 30%),
        linear-gradient(160deg, var(--body-grad-c1) 0%, var(--body-grad-c2) 45%, var(--body-grad-c3) 100%);
    overflow-x: hidden;
}

button,
input,
select,
textarea {
    font: inherit;
}

button {
    border: 0;
    cursor: pointer;
}

input,
select,
textarea {
    width: 100%;
    border: 1px solid var(--line);
    background: rgba(255, 255, 255, 0.86);
    color: var(--ink);
    border-radius: 14px;
    padding: 14px 16px;
    outline: none;
    transition: border-color 180ms ease, box-shadow 180ms ease, transform 180ms ease;
}

input:focus,
select:focus,
textarea:focus {
    border-color: rgba(108, 122, 224, 0.5);
    box-shadow: 0 0 0 5px rgba(108, 122, 224, 0.12);
    transform: translateY(-1px);
}

textarea {
    min-height: 110px;
    resize: vertical;
}

a {
    color: inherit;
}

.page-shell {
    position: relative;
    min-height: 100vh;
    padding: 32px;
}

.theme-toggle {
    position: relative;
    width: 58px;
    height: 32px;
    min-width: 58px;
    display: inline-grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    justify-items: center;
    padding: 0;
    border-radius: 999px;
    overflow: hidden;
    border: 1px solid var(--line);
    background: var(--surface-strong);
    color: var(--ink);
    font-weight: 800;
    box-shadow: var(--shadow-sm);
    transition: transform 180ms ease, background 180ms ease, color 180ms ease, border-color 180ms ease;
}

.theme-toggle:hover {
    transform: translateY(-2px);
}

.theme-toggle-moon,
.theme-toggle-sun {
    z-index: 1;
    font-size: 0.86rem;
    line-height: 1;
    color: rgba(29, 36, 51, 0.45);
    transition: color 180ms ease, transform 180ms ease, text-shadow 180ms ease;
}

.theme-toggle-thumb {
    position: absolute;
    left: 4px;
    top: 4px;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: linear-gradient(165deg, #ffffff, #dfe7f5);
    box-shadow: 0 3px 8px rgba(16, 25, 40, 0.26);
    transition: transform 220ms ease;
    z-index: 0;
}

.theme-toggle.is-light .theme-toggle-thumb {
    transform: translateX(29px);
}

.theme-toggle.is-dark .theme-toggle-thumb {
    transform: translateX(0);
}

.theme-toggle.is-light .theme-toggle-sun,
.theme-toggle.is-dark .theme-toggle-moon {
    color: var(--ink);
    transform: scale(1.05);
    text-shadow: 0 0 12px rgba(255, 255, 255, 0.35);
}

.orb,
.grid-glow {
    position: fixed;
    pointer-events: none;
    z-index: 0;
}

.orb {
    border-radius: 999px;
    filter: blur(10px);
    opacity: 0.75;
}

.orb-a {
    width: 280px;
    height: 280px;
    background: rgba(178, 184, 255, 0.26);
    top: -40px;
    left: -40px;
}

.orb-b {
    width: 360px;
    height: 360px;
    background: rgba(108, 122, 224, 0.14);
    right: -100px;
    top: 22%;
}

.grid-glow {
    inset: 0;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.18) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.18) 1px, transparent 1px);
    background-size: 38px 38px;
    mask-image: radial-gradient(circle at center, black 32%, transparent 86%);
    opacity: 0.25;
}

.login-panel,
.app-container {
    position: relative;
    z-index: 1;
    animation: rise-in 600ms ease;
}

.login-panel {
    min-height: calc(100vh - 64px);
    display: grid;
    grid-template-columns: minmax(0, 1.1fr) minmax(320px, 480px);
    gap: 28px;
    align-items: stretch;
}

.auth-hero,
.auth-card,
.panel {
    border: 1px solid rgba(255, 255, 255, 0.5);
    background: var(--surface);
    backdrop-filter: blur(18px);
    box-shadow: var(--shadow-lg);
}

.auth-hero {
    border-radius: var(--radius-xl);
    padding: 48px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    background:
        linear-gradient(145deg, rgba(250, 250, 250, 0.92), rgba(228, 229, 241, 0.9)),
        linear-gradient(135deg, rgba(108, 122, 224, 0.08), rgba(178, 184, 255, 0.1));
}

.auth-hero h1,
.app-title-group h2,
.course-header h2,
.panel-head h3,
.section-head h3,
.empty-workspace h3,
.auth-card h2 {
    font-family: "Space Grotesk", "Trebuchet MS", sans-serif;
    letter-spacing: -0.03em;
}

.auth-hero h1 {
    font-size: clamp(2.5rem, 5vw, 4.8rem);
    line-height: 0.96;
    margin: 16px 0;
    max-width: 10ch;
}

.hero-copy {
    max-width: 54ch;
    color: var(--ink-soft);
    font-size: 1.05rem;
    line-height: 1.75;
    margin-bottom: 32px;
}

.eyebrow,
.panel-label,
.brand-kicker {
    text-transform: uppercase;
    letter-spacing: 0.18em;
    font-size: 0.76rem;
    font-weight: 800;
    color: var(--accent);
    margin: 0;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
}

.hero-stat {
    position: relative;
    overflow: hidden;
    display: grid;
    align-content: start;
    gap: 8px;
    min-height: 138px;
    padding: 20px 18px 18px;
    border-radius: var(--radius-md);
    background:
        linear-gradient(165deg, rgba(250, 250, 250, 0.94), rgba(228, 229, 241, 0.82));
    border: 1px solid rgba(255, 255, 255, 0.78);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(12px);
    transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
}

.hero-stat::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent), var(--gold));
}

.hero-stat::after {
    content: "";
    position: absolute;
    top: -36px;
    right: -26px;
    width: 92px;
    height: 92px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(108, 122, 224, 0.22), rgba(108, 122, 224, 0));
    pointer-events: none;
}

.hero-stat:hover {
    transform: translateY(-3px);
    border-color: rgba(108, 122, 224, 0.34);
    box-shadow: var(--shadow-md);
}

.hero-stat strong {
    display: block;
    font-size: 1.07rem;
    line-height: 1.2;
    letter-spacing: 0.01em;
    margin: 0;
}

.hero-stat span {
    color: rgba(72, 75, 106, 0.82);
    line-height: 1.58;
    font-size: 0.94rem;
}

.auth-card {
    border-radius: var(--radius-xl);
    padding: 32px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 24px;
    background:
        linear-gradient(180deg, rgba(250, 250, 250, 0.96), rgba(228, 229, 241, 0.92));
}

.brand-row {
    display: flex;
    gap: 16px;
    align-items: center;
}

.brand-mark {
    width: 60px;
    height: 60px;
    border-radius: 20px;
    display: grid;
    place-items: center;
    font-family: "Space Grotesk", sans-serif;
    font-size: 1.25rem;
    font-weight: 700;
    color: #fff;
    background:
        linear-gradient(145deg, var(--accent), #7f8cff 60%, #9ca7ff 100%);
    box-shadow: 0 16px 34px rgba(108, 122, 224, 0.24);
}

.auth-card h2 {
    margin: 4px 0 0;
    font-size: 1.7rem;
}

.auth-inputs {
    display: grid;
    gap: 14px;
}

.field {
    display: grid;
    gap: 8px;
}

.field span {
    font-size: 0.9rem;
    color: var(--ink-soft);
    font-weight: 700;
}

.auth-actions,
.app-header-actions,
.course-create,
.message-input,
.assignment-actions {
    display: flex;
    gap: 12px;
}

.primary-btn,
.secondary-btn,
.ghost-btn,
.join-btn,
.course-action-btn,
.submit-assignment-btn,
.view-submissions-btn,
.submit-btn,
.cancel-btn,
#sendMessageBtn {
    padding: 12px 18px;
    border-radius: 14px;
    font-weight: 800;
    transition: transform 180ms ease, box-shadow 180ms ease, background 180ms ease, color 180ms ease;
}

.primary-btn,
#sendMessageBtn,
.submit-btn {
    color: #fff;
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-strong) 100%);
    box-shadow: 0 16px 28px rgba(108, 122, 224, 0.22);
}

.secondary-btn,
.view-submissions-btn,
.join-btn {
    color: var(--ink);
    background: linear-gradient(145deg, #f5f6ff, #dfe3ff);
    box-shadow: 0 12px 24px rgba(108, 122, 224, 0.16);
}

.ghost-btn,
.course-action-btn,
.cancel-btn {
    color: var(--ink);
    background: rgba(255, 255, 255, 0.8);
    border: 1px solid var(--line);
}

.primary-btn:hover,
.secondary-btn:hover,
.ghost-btn:hover,
.join-btn:hover,
.course-action-btn:hover,
.submit-assignment-btn:hover,
.view-submissions-btn:hover,
.submit-btn:hover,
.cancel-btn:hover,
#sendMessageBtn:hover {
    transform: translateY(-2px);
}

.submit-assignment-btn {
    color: #fff;
    background: linear-gradient(135deg, #1d5fd3, #2b7cf0);
}

.auth-actions > button,
.course-create > button,
.message-input > button {
    flex-shrink: 0;
}

.auth-message {
    min-height: 24px;
    font-size: 0.95rem;
    font-weight: 700;
}

.auth-message[data-type="error"] {
    color: var(--danger);
}

.auth-message[data-type="success"] {
    color: var(--accent);
}

.auth-message[data-type="info"] {
    color: var(--ink-soft);
}

.app-container {
    min-height: calc(100vh - 64px);
    display: flex;
    flex-direction: column;
    gap: 22px;
}

.app-header {
    display: flex;
    justify-content: space-between;
    gap: 18px;
    align-items: center;
    position: relative;
    z-index: 15;
    overflow: visible;
    border-radius: var(--radius-xl);
    padding: 22px 26px;
    background: rgba(228, 229, 241, 0.8);
    border: 1px solid rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(18px);
    box-shadow: var(--shadow-md);
}

.toolbar-search {
    flex: 1;
    min-width: 280px;
    max-width: 640px;
    position: relative;
    z-index: 30;
    display: grid;
    gap: 10px;
}

.search-toggle-btn {
    display: none;
    width: 48px;
    min-width: 48px;
    height: 48px;
    padding: 0;
    place-items: center;
}

.search-toggle-icon {
    position: relative;
    width: 18px;
    height: 18px;
    border: 2px solid currentColor;
    border-radius: 50%;
}

.search-toggle-icon::after {
    content: "";
    position: absolute;
    right: -7px;
    bottom: -4px;
    width: 9px;
    height: 2px;
    border-radius: 999px;
    background: currentColor;
    transform: rotate(45deg);
}

.search-panel {
    display: grid;
    gap: 10px;
}

.search-shell {
    position: relative;
    z-index: 35;
}

.search-input-row {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 10px;
}

.search-shell input {
    padding-right: 18px;
}

.search-execute-btn {
    white-space: nowrap;
}

.search-results {
    position: absolute;
    top: calc(100% + 10px);
    left: 0;
    right: 0;
    display: grid;
    gap: 8px;
    padding: 12px;
    border-radius: 18px;
    background: rgba(250, 250, 250, 0.96);
    border: 1px solid var(--line);
    box-shadow: var(--shadow-md);
    z-index: 50;
    max-height: 360px;
    overflow: auto;
}

.search-result-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 12px 14px;
    border-radius: 14px;
    background: rgba(228, 229, 241, 0.52);
    border: 1px solid rgba(72, 75, 106, 0.08);
}

.search-result-main {
    min-width: 0;
    cursor: pointer;
}

.search-result-title {
    font-weight: 800;
}

.search-result-meta {
    margin-top: 4px;
    font-size: 0.84rem;
    color: var(--ink-soft);
}

.search-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.search-filter {
    padding: 8px 12px;
    border-radius: 999px;
    background: rgba(228, 229, 241, 0.74);
    color: var(--ink-soft);
    font-weight: 800;
}

.search-filter.active {
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    color: #fff;
}

.app-title-group h2 {
    margin: 6px 0 0;
    font-size: clamp(1.8rem, 4vw, 2.7rem);
}

.session-badge,
.user-meta,
.count-pill {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 14px;
    border-radius: 999px;
    font-size: 0.9rem;
    font-weight: 800;
}

.session-badge {
    background: rgba(108, 122, 224, 0.12);
    color: var(--accent-strong);
}

.app-header-actions {
    position: relative;
    z-index: 10;
}

.user-meta {
    background: rgba(29, 36, 51, 0.06);
    color: var(--ink-soft);
}

.count-pill {
    background: rgba(29, 36, 51, 0.06);
    color: var(--ink-soft);
}

.app-body {
    display: grid;
    grid-template-columns: minmax(260px, 320px) minmax(0, 1fr) minmax(260px, 320px);
    gap: 20px;
    min-height: 0;
    flex: 1;
}

.home-btn {
    width: 100%;
    margin-top: 14px;
}

.panel,
.empty-workspace,
.course-content-panel,
.home-workspace,
.private-workspace,
.profile-workspace {
    border-radius: var(--radius-xl);
    padding: 22px;
}

.panel-head,
.section-head,
.course-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 14px;
    margin-bottom: 18px;
}

.panel-head h3,
.section-head h3,
.course-header h2,
.empty-workspace h3 {
    margin: 6px 0 0;
}

.course-create {
    margin-bottom: 18px;
    align-items: center;
}

.course-create input {
    flex: 1;
}

.course-list,
.discover-list,
.notes-list,
.message-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.course-list,
.discover-list {
    display: grid;
    gap: 12px;
}

.course-item,
.discover-item,
.note-item {
    border-radius: var(--radius-md);
    border: 1px solid rgba(255, 255, 255, 0.55);
    background: linear-gradient(180deg, rgba(250, 250, 250, 0.95), rgba(228, 229, 241, 0.9));
    box-shadow: var(--shadow-sm);
    transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.course-item {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 10px;
    align-items: center;
    padding-right: 12px;
}

.course-item:hover,
.discover-item:hover,
.note-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: rgba(108, 122, 224, 0.28);
}

.course-item.selected {
    border-color: rgba(108, 122, 224, 0.38);
    background: linear-gradient(180deg, rgba(228, 229, 241, 0.95), rgba(210, 211, 219, 0.92));
}

.course-item-button,
.discover-item-shell {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 16px;
    background: transparent;
    color: inherit;
    text-align: left;
}

.course-item-button {
    border: 0;
    cursor: pointer;
}

.course-main,
.discover-main {
    min-width: 0;
}

.course-name,
.discover-name {
    font-weight: 800;
    margin-bottom: 6px;
}

.course-meta,
.discover-meta {
    color: var(--ink-soft);
    font-size: 0.88rem;
}

.course-badge {
    display: inline-flex;
    padding: 7px 10px;
    border-radius: 999px;
    background: rgba(108, 122, 224, 0.1);
    color: var(--accent-strong);
    font-size: 0.76rem;
    font-weight: 800;
}

.workspace {
    min-width: 0;
    display: flex;
}

.empty-workspace,
.course-content-panel,
.home-workspace,
.private-workspace,
.profile-workspace {
    width: 100%;
}

.home-workspace,
.course-content-panel,
.private-workspace,
.profile-workspace {
    display: none;
}

.home-workspace.active-view,
.course-content-panel.active-view,
.private-workspace.active-view,
.profile-workspace.active-view {
    display: flex;
}

.home-workspace {
    flex-direction: column;
    gap: 18px;
    background:
        linear-gradient(180deg, rgba(250, 250, 250, 0.94), rgba(228, 229, 241, 0.9));
}

.home-hero {
    display: flex;
    justify-content: space-between;
    gap: 18px;
    align-items: flex-start;
}

.home-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
}

.home-grid-secondary {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.home-section {
    border-radius: 22px;
    padding: 18px;
    background: rgba(250, 250, 250, 0.78);
    border: 1px solid rgba(72, 75, 106, 0.08);
}

.friends-list,
.recommendation-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    gap: 12px;
}

.friend-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    padding: 16px;
    border-radius: 18px;
    background: linear-gradient(180deg, rgba(250, 250, 250, 0.95), rgba(228, 229, 241, 0.92));
    border: 1px solid rgba(72, 75, 106, 0.08);
}

.friend-main {
    min-width: 0;
}

.friend-name {
    font-weight: 800;
}

.friend-meta {
    margin-top: 4px;
    font-size: 0.87rem;
    color: var(--ink-soft);
    line-height: 1.55;
}

.friend-actions {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.private-chat-header-actions {
    display: grid;
    justify-items: end;
    gap: 10px;
}

.mini-btn {
    padding: 9px 12px;
    border-radius: 12px;
    font-weight: 800;
    background: rgba(228, 229, 241, 0.9);
    color: var(--ink);
    border: 1px solid rgba(72, 75, 106, 0.12);
}

.danger-btn {
    padding: 10px 14px;
    border-radius: 12px;
    font-weight: 800;
    color: #fff;
    background: linear-gradient(145deg, #dc5d63, #b93d4b);
    border: 1px solid rgba(117, 25, 34, 0.18);
    box-shadow: 0 12px 24px rgba(185, 61, 75, 0.22);
}

.empty-workspace {
    display: grid;
    align-content: center;
    min-height: 100%;
    text-align: center;
    background:
        radial-gradient(circle at top, rgba(108, 122, 224, 0.1), transparent 35%),
        linear-gradient(180deg, rgba(250, 250, 250, 0.9), rgba(228, 229, 241, 0.94));
}

.empty-workspace p {
    max-width: 48ch;
    margin: 10px auto 0;
    color: var(--ink-soft);
    line-height: 1.7;
}

.course-content-panel {
    flex-direction: column;
    gap: 18px;
    min-height: 0;
    background:
        linear-gradient(180deg, rgba(250, 250, 250, 0.92), rgba(228, 229, 241, 0.88));
}

.workspace-subtitle,
.online-users,
.typing-indicator {
    color: var(--ink-soft);
    margin: 8px 0 0;
}

.online-users {
    max-width: 240px;
    text-align: right;
    font-weight: 700;
}

.course-tabs {
    display: inline-flex;
    gap: 8px;
    padding: 6px;
    width: fit-content;
    border-radius: 16px;
    background: rgba(29, 36, 51, 0.05);
}

.tab-btn {
    border-radius: 12px;
    padding: 10px 16px;
    background: transparent;
    color: var(--ink-soft);
    font-weight: 800;
}

.tab-btn.active {
    background: #fff;
    color: var(--ink);
    box-shadow: 0 8px 18px rgba(29, 36, 51, 0.08);
}

.tab-content,
.tab-pane,
.chat-panel,
.assignment-list {
    min-height: 0;
}

.tab-content {
    display: flex;
    flex-direction: column;
    flex: 1;
}

.tab-pane {
    display: none;
    flex: 1;
    flex-direction: column;
    gap: 16px;
}

.tab-pane.active {
    display: flex;
}

.chat-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    border-radius: 22px;
    background: linear-gradient(180deg, rgba(228, 229, 241, 0.74), rgba(250, 250, 250, 0.88));
    border: 1px solid rgba(29, 36, 51, 0.08);
    padding: 16px;
    min-height: 520px;
    max-height: 520px;
}

.private-workspace {
    flex-direction: column;
    gap: 18px;
    min-height: 0;
    background:
        linear-gradient(180deg, rgba(250, 250, 250, 0.92), rgba(228, 229, 241, 0.88));
}

.profile-workspace {
    flex-direction: column;
    gap: 18px;
    background:
        linear-gradient(180deg, rgba(250, 250, 250, 0.92), rgba(228, 229, 241, 0.88));
}

.search-workspace {
    display: none;
    flex-direction: column;
    gap: 18px;
    width: 100%;
    border-radius: var(--radius-xl);
    padding: 22px;
    background:
        linear-gradient(180deg, rgba(250, 250, 250, 0.92), rgba(228, 229, 241, 0.88));
}

.search-workspace.active-view {
    display: flex;
}

.profile-grid {
    display: grid;
    grid-template-columns: minmax(280px, 360px) minmax(0, 1fr);
    gap: 18px;
}

.profile-card,
.user-summary-content {
    display: grid;
    gap: 12px;
}

.profile-danger-zone {
    margin-top: 10px;
    padding-top: 12px;
    border-top: 1px solid rgba(72, 75, 106, 0.12);
}

.search-workspace-content {
    display: grid;
    gap: 12px;
}

.profile-stat {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    padding: 12px 14px;
    border-radius: 14px;
    background: rgba(228, 229, 241, 0.52);
}

.profile-stat strong {
    font-size: 0.92rem;
}

.profile-stat span {
    color: var(--ink-soft);
}

.typing-indicator {
    min-height: 24px;
    font-size: 0.9rem;
    padding: 0 2px 8px;
}

.message-list {
    display: flex;
    flex-direction: column;
    gap: 14px;
    overflow: auto;
    padding-right: 6px;
    flex: 1;
}

.message-item {
    display: flex;
    align-items: flex-end;
    gap: 10px;
}

.message-item.own {
    justify-content: flex-end;
}

.message-avatar {
    width: 38px;
    height: 38px;
    min-width: 38px;
    border-radius: 50%;
    display: grid;
    place-items: center;
    font-weight: 800;
    color: #fff;
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    box-shadow: var(--shadow-sm);
}

.message-avatar[disabled] {
    opacity: 0.75;
    cursor: default;
}

.message-bubble {
    max-width: min(78%, 580px);
    padding: 14px 16px;
    border-radius: 18px;
    background: rgba(250, 250, 250, 0.95);
    border: 1px solid rgba(29, 36, 51, 0.08);
    box-shadow: var(--shadow-sm);
}

.message-item.own .message-bubble {
    background: linear-gradient(145deg, rgba(108, 122, 224, 0.14), rgba(238, 241, 255, 0.96));
}

.message-item:not(.own) .message-bubble {
    background: linear-gradient(165deg, rgba(250, 250, 250, 0.98), rgba(228, 229, 241, 0.95));
    border-color: rgba(29, 36, 51, 0.18);
    box-shadow: 0 12px 22px rgba(25, 34, 52, 0.12);
}

.message-meta {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    font-size: 0.8rem;
    color: var(--ink-soft);
    margin-bottom: 8px;
}

.message-author {
    font-weight: 800;
    color: var(--ink);
}

.message-text {
    color: var(--ink);
    line-height: 1.7;
    font-weight: 600;
    white-space: pre-wrap;
    word-break: break-word;
}

.message-input {
    align-items: center;
}

.message-input input {
    flex: 1;
    background: rgba(255, 255, 255, 0.92);
}

.load-older-btn {
    align-self: center;
    margin-bottom: 12px;
}

.user-summary-modal {
    position: fixed;
    inset: 0;
    z-index: 20;
    display: grid;
    place-items: center;
    padding: 20px;
    background: rgba(20, 24, 40, 0.28);
    backdrop-filter: blur(10px);
}

.user-summary-card {
    width: min(100%, 560px);
    border-radius: 24px;
    padding: 22px;
    background: rgba(250, 250, 250, 0.97);
    border: 1px solid var(--line);
    box-shadow: var(--shadow-lg);
}

.delete-friend-card {
    width: min(100%, 520px);
}

.delete-warning-copy {
    padding: 14px 16px;
    border-radius: 16px;
    background: rgba(220, 93, 99, 0.1);
    border: 1px solid rgba(185, 61, 75, 0.16);
    color: var(--ink);
    line-height: 1.6;
}

.modal-actions {
    justify-content: flex-end;
    margin-top: 18px;
}

.search-result-card {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    padding: 16px;
    border-radius: 18px;
    background: rgba(250, 250, 250, 0.9);
    border: 1px solid rgba(72, 75, 106, 0.08);
}

.search-filter {
    padding: 8px 12px;
    border-radius: 999px;
    background: rgba(228, 229, 241, 0.74);
    color: var(--ink);
    font-weight: 800;
    border: 1px solid rgba(72, 75, 106, 0.1);
}

.upload-section,
.create-assignment,
.course-admin-tools {
    display: grid;
    gap: 12px;
    padding: 18px;
    border-radius: 22px;
    background: rgba(255, 255, 255, 0.7);
    border: 1px solid rgba(29, 36, 51, 0.08);
}

.course-members-list {
    display: grid;
    gap: 12px;
}

.course-member-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 16px;
    border-radius: 18px;
    background: rgba(228, 229, 241, 0.68);
    border: 1px solid rgba(29, 36, 51, 0.08);
}

.course-member-main {
    min-width: 0;
}

.course-member-name {
    font-weight: 800;
    margin-bottom: 4px;
}

.course-member-meta {
    color: var(--ink-soft);
    font-size: 0.88rem;
}

.role-actions {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.role-btn {
    padding: 10px 14px;
    border-radius: 12px;
    font-weight: 800;
    background: rgba(255, 255, 255, 0.82);
    border: 1px solid rgba(29, 36, 51, 0.1);
}

.notes-list {
    display: grid;
    gap: 12px;
}

.note-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 16px;
}

.note-main {
    min-width: 0;
}

.note-title {
    font-weight: 800;
    margin-bottom: 6px;
}

.note-meta {
    color: var(--ink-soft);
    font-size: 0.88rem;
}

.note-link {
    text-decoration: none;
    color: var(--accent-strong);
    font-weight: 800;
}

.assignment-list {
    display: grid;
    gap: 16px;
    overflow: auto;
}

.assignment-item {
    padding: 20px;
    border-radius: 22px;
    background: rgba(255, 255, 255, 0.78);
    border: 1px solid rgba(29, 36, 51, 0.08);
    box-shadow: var(--shadow-sm);
}

.assignment-item h4,
.submission-item h5 {
    margin: 0 0 10px;
    font-family: "Space Grotesk", sans-serif;
}

.assignment-item p,
.submission-item p,
.empty-list {
    color: var(--ink-soft);
    line-height: 1.65;
}

.assignment-item p {
    margin: 7px 0;
}

.assignment-actions {
    margin-top: 14px;
    flex-wrap: wrap;
}

.status-chip {
    display: inline-flex;
    align-items: center;
    padding: 6px 10px;
    border-radius: 999px;
    font-size: 0.76rem;
    font-weight: 800;
}

.status-chip.overdue {
    color: #8f2e28;
    background: rgba(192, 75, 67, 0.12);
}

.status-chip.active {
    color: var(--accent-strong);
    background: rgba(108, 122, 224, 0.12);
}

.submission-form,
.submissions-list {
    margin-top: 16px;
    padding: 16px;
    border-radius: 18px;
    background: rgba(228, 229, 241, 0.72);
    border: 1px solid rgba(29, 36, 51, 0.08);
}

.submission-form textarea {
    margin-bottom: 10px;
}

.submissions-list {
    display: grid;
    gap: 12px;
}

.submission-item {
    padding-bottom: 12px;
    border-bottom: 1px solid rgba(29, 36, 51, 0.08);
}

.submission-item:last-child {
    padding-bottom: 0;
    border-bottom: 0;
}

.section-head.compact {
    margin-bottom: 8px;
}

.hidden {
    display: none !important;
}

.empty-list {
    padding: 18px;
    border-radius: 18px;
    background: rgba(255, 255, 255, 0.6);
    border: 1px dashed rgba(29, 36, 51, 0.12);
}

html[data-theme="dark"] {
    --bg: #0c1524;
    --bg-strong: #18253a;
    --surface: rgba(23, 35, 54, 0.82);
    --surface-strong: #1f2d44;
    --surface-alt: #20314b;
    --ink: #e6edf8;
    --ink-soft: #a6b4cc;
    --line: rgba(173, 194, 225, 0.22);
    --line-strong: rgba(173, 194, 225, 0.34);
    --accent: #39bdb1;
    --accent-strong: #87efe0;
    --accent-soft: rgba(57, 189, 177, 0.16);
    --warm: #f08f62;
    --gold: #e4be67;
    --danger: #f07f74;
    --shadow-lg: 0 28px 60px rgba(2, 8, 20, 0.62);
    --shadow-md: 0 16px 38px rgba(2, 8, 20, 0.5);
    --shadow-sm: 0 8px 22px rgba(2, 8, 20, 0.44);
    --body-grad-a: rgba(240, 143, 98, 0.16);
    --body-grad-b: rgba(57, 189, 177, 0.2);
    --body-grad-c1: #08101d;
    --body-grad-c2: #111b2d;
    --body-grad-c3: #0d1728;
}

html[data-theme="dark"] .grid-glow {
    background-image:
        linear-gradient(rgba(176, 198, 232, 0.12) 1px, transparent 1px),
        linear-gradient(90deg, rgba(176, 198, 232, 0.12) 1px, transparent 1px);
    opacity: 0.2;
}

html[data-theme="dark"] .orb-a {
    background: rgba(228, 190, 103, 0.24);
}

html[data-theme="dark"] .orb-b {
    background: rgba(57, 189, 177, 0.2);
}

html[data-theme="dark"] input,
html[data-theme="dark"] select,
html[data-theme="dark"] textarea {
    background: rgba(17, 26, 42, 0.9);
    color: var(--ink);
    border-color: var(--line);
}

html[data-theme="dark"] .auth-hero,
html[data-theme="dark"] .auth-card,
html[data-theme="dark"] .panel,
html[data-theme="dark"] .app-header,
html[data-theme="dark"] .course-content-panel,
html[data-theme="dark"] .empty-workspace,
html[data-theme="dark"] .chat-panel,
html[data-theme="dark"] .upload-section,
html[data-theme="dark"] .create-assignment,
html[data-theme="dark"] .course-admin-tools,
html[data-theme="dark"] .assignment-item,
html[data-theme="dark"] .submissions-list,
html[data-theme="dark"] .submission-form,
html[data-theme="dark"] .course-member-item,
html[data-theme="dark"] .message-bubble,
html[data-theme="dark"] .hero-stat,
html[data-theme="dark"] .course-item,
html[data-theme="dark"] .discover-item,
html[data-theme="dark"] .note-item,
html[data-theme="dark"] .empty-list,
html[data-theme="dark"] .tab-btn.active {
    border-color: var(--line);
}

html[data-theme="dark"] .auth-hero {
    background:
        linear-gradient(145deg, rgba(23, 37, 58, 0.95), rgba(18, 29, 47, 0.95)),
        linear-gradient(135deg, rgba(57, 189, 177, 0.12), rgba(240, 143, 98, 0.1));
}

html[data-theme="dark"] .auth-card {
    background:
        linear-gradient(180deg, rgba(22, 34, 53, 0.96), rgba(16, 25, 40, 0.94));
}

html[data-theme="dark"] .app-header {
    background: rgba(20, 31, 49, 0.8);
}

html[data-theme="dark"] .course-item,
html[data-theme="dark"] .discover-item,
html[data-theme="dark"] .note-item,
html[data-theme="dark"] .assignment-item,
html[data-theme="dark"] .course-member-item,
html[data-theme="dark"] .empty-list,
html[data-theme="dark"] .submission-form,
html[data-theme="dark"] .submissions-list,
html[data-theme="dark"] .upload-section,
html[data-theme="dark"] .create-assignment,
html[data-theme="dark"] .course-admin-tools,
html[data-theme="dark"] .home-section,
html[data-theme="dark"] .friend-item,
html[data-theme="dark"] .search-result-item {
    background: rgba(22, 34, 53, 0.86);
}

html[data-theme="dark"] .empty-workspace,
html[data-theme="dark"] .course-content-panel,
html[data-theme="dark"] .chat-panel,
html[data-theme="dark"] .home-workspace,
html[data-theme="dark"] .private-workspace,
html[data-theme="dark"] .profile-workspace,
html[data-theme="dark"] .search-workspace,
html[data-theme="dark"] .search-results {
    background: rgba(20, 30, 47, 0.84);
}

html[data-theme="dark"] .profile-stat,
html[data-theme="dark"] .user-summary-card,
html[data-theme="dark"] .search-result-card {
    background: rgba(22, 34, 53, 0.92);
}

html[data-theme="dark"] .delete-warning-copy {
    background: rgba(240, 127, 116, 0.14);
    border-color: rgba(240, 127, 116, 0.26);
    color: var(--ink);
}

html[data-theme="dark"] .danger-btn {
    background: linear-gradient(145deg, #e07a7a, #bf4b57);
    color: #fff;
}

html[data-theme="dark"] .search-filter {
    background: rgba(22, 34, 53, 0.95);
    color: #e6edf8;
    border-color: rgba(173, 194, 225, 0.22);
}

html[data-theme="dark"] .message-item.own .message-bubble {
    background: linear-gradient(145deg, rgba(57, 189, 177, 0.22), rgba(29, 47, 73, 0.94));
}

html[data-theme="dark"] .message-item:not(.own) .message-bubble {
    background: linear-gradient(165deg, rgba(36, 50, 74, 0.96), rgba(23, 35, 54, 0.94));
    border-color: rgba(183, 202, 232, 0.3);
    box-shadow: 0 10px 20px rgba(2, 8, 20, 0.4);
}

html[data-theme="dark"] .message-item:not(.own) .message-author {
    color: #f2f7ff;
}

html[data-theme="dark"] .message-item:not(.own) .message-meta {
    color: rgba(203, 218, 241, 0.88);
}

html[data-theme="dark"] .message-item:not(.own) .message-text {
    color: #eaf2ff;
}

html[data-theme="dark"] .course-tabs {
    background: rgba(167, 187, 219, 0.12);
}

html[data-theme="dark"] .hero-stat {
    background:
        linear-gradient(165deg, rgba(26, 39, 60, 0.95), rgba(17, 27, 43, 0.92));
}

html[data-theme="dark"] .hero-stat::before {
    background: linear-gradient(90deg, #55d4c7, #f0bf6b);
}

html[data-theme="dark"] .hero-stat::after {
    background: radial-gradient(circle, rgba(85, 212, 199, 0.28), rgba(85, 212, 199, 0));
}

html[data-theme="dark"] .hero-stat span {
    color: rgba(220, 230, 245, 0.84);
}

html[data-theme="dark"] .tab-btn.active {
    background: rgba(15, 25, 40, 0.92);
    color: var(--ink);
}

html[data-theme="dark"] .ghost-btn,
html[data-theme="dark"] .course-action-btn,
html[data-theme="dark"] .cancel-btn,
html[data-theme="dark"] .role-btn,
html[data-theme="dark"] .theme-toggle {
    background: rgba(17, 26, 42, 0.9);
    color: var(--ink);
}

html[data-theme="dark"] .theme-toggle {
    opacity: 0.92;
    background: rgba(17, 26, 42, 0.95);
}

html[data-theme="dark"] .theme-toggle-thumb {
    background: linear-gradient(165deg, #dfe7f5, #aebad1);
    box-shadow: 0 3px 8px rgba(1, 6, 15, 0.45);
}

html[data-theme="dark"] .theme-toggle-moon,
html[data-theme="dark"] .theme-toggle-sun {
    color: rgba(230, 237, 248, 0.46);
}

html[data-theme="dark"] .theme-toggle.is-light .theme-toggle-sun,
html[data-theme="dark"] .theme-toggle.is-dark .theme-toggle-moon {
    color: #f3f7ff;
    text-shadow: 0 0 12px rgba(173, 194, 225, 0.45);
}

html[data-theme="dark"] .secondary-btn,
html[data-theme="dark"] .view-submissions-btn,
html[data-theme="dark"] .join-btn,
html[data-theme="dark"] .mini-btn {
    color: #082018;
    background: linear-gradient(145deg, #f3cb76, #d89f48);
}

html[data-theme="dark"] .session-badge {
    color: #041a18;
    background: rgba(135, 239, 224, 0.82);
}

html[data-theme="dark"] .user-meta,
html[data-theme="dark"] .count-pill {
    background: rgba(164, 183, 214, 0.18);
    color: var(--ink-soft);
}

@keyframes rise-in {
    from {
        opacity: 0;
        transform: translateY(16px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 1180px) {
    .app-body {
        grid-template-columns: 280px minmax(0, 1fr);
    }

    .discover-panel {
        grid-column: 1 / -1;
    }
}

@media (max-width: 980px) {
    .page-shell {
        padding: 18px;
    }

    .login-panel {
        grid-template-columns: 1fr;
        min-height: auto;
    }

    .auth-hero {
        padding: 32px;
    }

    .hero-stats {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .hero-stat {
        min-height: auto;
    }

    .app-header,
    .app-body {
        grid-template-columns: 1fr;
        display: grid;
    }

    .toolbar-search,
    .app-header-actions,
    .home-grid,
    .home-grid-secondary,
    .home-hero,
    .profile-grid {
        grid-template-columns: 1fr;
        display: grid;
    }

    .search-input-row {
        grid-template-columns: 1fr;
    }

    .app-header {
        justify-content: stretch;
        grid-template-columns: minmax(0, 1fr) auto;
        align-items: start;
    }

    .toolbar-search {
        min-width: 0;
        width: auto;
        justify-items: end;
        justify-self: end;
    }

    .search-toggle-btn {
        display: grid;
    }

    .search-panel {
        display: none;
        width: 100%;
    }

    .toolbar-search.search-open {
        grid-column: 1 / -1;
        width: 100%;
        justify-self: stretch;
    }

    .toolbar-search.search-open .search-toggle-btn {
        justify-self: end;
    }

    .toolbar-search.search-open .search-panel {
        display: grid;
    }

    .app-header-actions {
        grid-column: 1 / -1;
        flex-wrap: wrap;
    }

    .online-users {
        text-align: left;
        max-width: none;
    }
}

@media (max-width: 680px) {
    .page-shell {
        padding: 14px;
    }

    .auth-card,
    .auth-hero,
    .panel,
    .empty-workspace,
    .course-content-panel,
    .home-workspace,
    .private-workspace,
    .profile-workspace,
    .search-workspace,
    .app-header {
        border-radius: 22px;
    }

    .auth-hero,
    .auth-card,
    .panel,
    .empty-workspace,
    .course-content-panel,
    .home-workspace,
    .private-workspace,
    .profile-workspace,
    .search-workspace,
    .app-header {
        padding: 18px;
    }

    .auth-hero h1 {
        font-size: 2.5rem;
    }

    .auth-actions,
    .app-header-actions,
    .course-create,
    .message-input,
    .assignment-actions {
        flex-direction: column;
    }

    .course-tabs {
        width: 100%;
        display: grid;
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .tab-btn {
        width: 100%;
    }

    .message-bubble {
        max-width: 100%;
    }

    .course-item-button,
    .discover-item-shell,
    .note-item {
        flex-direction: column;
        align-items: flex-start;
    }
}