:root {
    --primary-color: #4F46E5;
    --secondary-color: #7C3AED;
    --accent-primary: #A78BFA;
    --accent-color: #06b6d4;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;

    --bg-primary: #0D0C1D;
    --bg-secondary: #1A1A2E;
    --bg-tertiary: #211f3d;
    --surface-glass: rgba(255, 255, 255, 0.05);
    --surface-glass-hover: rgba(255, 255, 255, 0.08);
    --surface-glass-strong: rgba(255, 255, 255, 0.12);
    --border-glass: rgba(255, 255, 255, 0.1);
    --border-glass-hover: rgba(255, 255, 255, 0.2);
    --dropdown-bg: #0D0C1D;
    --card-bg: rgba(255, 255, 255, 0.03);
    --card-bg-hover: rgba(255, 255, 255, 0.06);

    --text-primary: #FFFFFF;
    --text-secondary: #9CA3AF;
    --text-tertiary: #6B7280;
    --text-muted: var(--text-secondary);

    --primary: var(--primary-color);
    --primary-hover: #4338CA;
    --secondary: var(--secondary-color);
    --accent: var(--accent-primary);
    --accent-soft: #DDD6FE;
    --success: var(--success-color);
    --warning: var(--warning-color);
    --danger: var(--danger-color);
    --border: var(--border-glass);
    --border-strong: var(--border-glass-hover);

    --shadow-sm: 0 10px 30px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 18px 44px rgba(0, 0, 0, 0.28);
    --shadow-lg: 0 32px 90px rgba(0, 0, 0, 0.35);
    --shadow-glow: 0 0 40px rgba(79, 70, 229, 0.2);

    --radius-sm: 0.55rem;
    --radius-md: 0.9rem;
    --radius-lg: 1.2rem;
    --radius-xl: 1.6rem;
    --radius-2xl: 1.85rem;
    --radius-full: 999px;
    --transition-speed: 0.3s;

    --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family: var(--font);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    position: relative;
    isolation: isolate;
}

body::before {
    content: '';
    position: fixed;
    top: -20%;
    left: -20%;
    width: 60%;
    height: 60%;
    background: radial-gradient(circle, var(--primary-color) 0%, transparent 70%);
    opacity: 0.15;
    filter: blur(100px);
    z-index: -1;
    pointer-events: none;
    animation: pulse-glow-1 15s infinite alternate;
}

body::after {
    content: '';
    position: fixed;
    bottom: -20%;
    right: -20%;
    width: 60%;
    height: 60%;
    background: radial-gradient(circle, var(--accent-primary) 0%, transparent 70%);
    opacity: 0.15;
    filter: blur(100px);
    z-index: -1;
    pointer-events: none;
    animation: pulse-glow-2 12s infinite alternate;
}

@keyframes pulse-glow-1 {
    from { transform: scale(0.8) rotate(0deg); opacity: 0.1; }
    to { transform: scale(1.2) rotate(45deg); opacity: 0.2; }
}

@keyframes pulse-glow-2 {
    from { transform: scale(1.2) rotate(0deg); opacity: 0.2; }
    to { transform: scale(0.8) rotate(-45deg); opacity: 0.1; }
}

a {
    color: var(--text-primary);
    text-decoration: none;
    transition: color var(--transition-speed);
}

a:hover {
    color: var(--accent-primary);
}

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

img {
    max-width: 100%;
    display: block;
}

ul {
    margin: 0;
    padding: 0;
    list-style: none;
}

::selection {
    background: rgba(79, 70, 229, 0.35);
    color: var(--text-primary);
}

/* ── Nav ── */

.nav-container {
    position: sticky;
    top: 0;
    z-index: 50;
    background: var(--surface-glass);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-glass);
}

.nav-content {
    max-width: 1280px;
    height: 4rem;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    align-items: center;
}

.nav-links,
.auth-buttons {
    display: none;
}

.auth-buttons-mobile {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
    gap: 0.75rem;
}

.nav-logo-link {
    display: inline-flex;
    align-items: center;
    height: 100%;
    padding: 0.25rem 0;
    margin-right: 1rem;
}

.nav-logo-img {
    height: 32px;
    width: auto;
    max-height: calc(100% - 0.5rem);
    display: block;
}

.nav-link {
    padding: 0.5rem 0.75rem;
    border-radius: 0.375rem;
    color: var(--text-primary);
    display: inline-flex;
    align-items: center;
    white-space: nowrap;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

.nav-link:hover {
    background-color: var(--surface-glass-hover);
    color: var(--text-primary);
}

.nav-link.active {
    background-color: var(--surface-glass-hover);
    border: 1px solid var(--border-glass);
}

.nav-item.nav-dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-arrow {
    margin-left: 0.35rem;
    font-size: 0.7rem;
    transition: transform 0.15s ease;
}

.nav-dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 220px;
    padding: 0.5rem 0;
    background: var(--dropdown-bg);
    backdrop-filter: blur(15px);
    border: 1px solid var(--border-glass);
    border-radius: 0.5rem;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(5px);
    transition: opacity var(--transition-speed) ease, visibility var(--transition-speed) ease, transform var(--transition-speed) ease;
}

.nav-item.nav-dropdown:hover > .nav-dropdown-menu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
}

.nav-item.nav-dropdown:hover > .nav-dropdown-toggle .dropdown-arrow {
    transform: rotate(180deg);
}

.nav-dropdown-item {
    display: block;
    padding: 0.6rem 1.2rem;
    color: var(--text-primary);
}

.nav-dropdown-item:hover,
.nav-dropdown-item.active {
    background-color: var(--surface-glass-hover);
    color: var(--text-primary);
}

.mobile-menu-button {
    display: block;
    background: none;
    border: 0;
    color: var(--text-primary);
    padding: 0.5rem;
    cursor: pointer;
    transition: opacity var(--transition-speed);
    z-index: 51;
}

.mobile-menu-button:hover {
    opacity: 0.8;
}

.mobile-menu {
    display: none;
    position: fixed;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    backdrop-filter: blur(12px);
    padding: 1rem 0;
    z-index: 49;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    overflow-y: auto;
    transform: translateY(-100%);
    transition: transform var(--transition-speed) ease-out;
}

.mobile-menu.active {
    display: block;
    transform: translateY(0);
}

.mobile-menu .nav-link:not(.sub-link),
.mobile-menu .mobile-submenu-toggle {
    display: block;
    padding: 0.9rem 1.5rem;
    text-align: left;
    border-bottom: 1px solid var(--border-glass);
    width: 100%;
    color: var(--text-primary);
}

.mobile-menu > *:not(.mobile-menu-section):not(.auth-buttons-mobile):last-of-type {
    border-bottom: none;
}

.mobile-menu .mobile-menu-section:last-of-type > .mobile-submenu-toggle {
    border-bottom: none;
}

.mobile-submenu-toggle {
    background: none;
    border: none;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.mobile-submenu-toggle[aria-expanded="true"] .dropdown-arrow {
    transform: rotate(180deg);
}

.mobile-submenu {
    background-color: rgba(0, 0, 0, 0.1);
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.3s ease-out;
}

.mobile-submenu .sub-link {
    display: block;
    padding: 0.75rem 1.5rem 0.75rem 2.5rem;
    font-size: 0.92rem;
    color: var(--text-secondary);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.mobile-menu .auth-buttons-mobile {
    border-top: 1px solid var(--border-glass);
    padding: 1.5rem 1.5rem 1rem;
    margin-top: 1rem;
}

.banner-container {
    width: 100%;
    background: var(--bg-primary);
    position: relative;
    overflow: hidden;
}

.banner-content {
    margin: 0 auto;
    position: relative;
    z-index: 10;
}

.banner-link {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 0.75rem;
    text-decoration: none;
    color: var(--text-primary);
    background: var(--surface-glass);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-glass);
    text-align: center;
    font-size: 0.875rem;
    transition: opacity 0.3s ease;
}

.banner-link:hover {
    opacity: 0.9;
    color: var(--text-primary);
}

.button {
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    border: none;
    cursor: pointer;
    transition: all var(--transition-speed);
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    text-align: center;
    font-size: 0.95rem;
}

.button-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--text-primary);
    border: 1px solid transparent;
}

.button-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(79, 70, 229, 0.4);
    color: var(--text-primary);
}

.button-outline,
.button-secondary {
    background: transparent;
    border: 1px solid var(--border-glass);
    color: var(--text-primary);
}

.button-outline:hover,
.button-secondary:hover {
    background: var(--surface-glass-hover);
    border-color: var(--border-glass-hover);
    color: var(--text-primary);
}

.profile-icon,
.submit-icon {
    padding: 10px !important;
}

.profile-menu.show {
    background: var(--bg-primary) !important;
}

/* ── Layout ── */

.section-shell,
.study-shell {
    width: min(1320px, calc(100% - 2rem));
    margin: 0 auto;
}

.quiz-sprint-app .study-shell {
    width: min(1480px, calc(100% - 2rem));
}

.workspace-header {
    position: relative;
    padding: 1.35rem 0 1rem;
    overflow: hidden;
}

.workspace-header-shell {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: minmax(0, 1.25fr) minmax(300px, 0.8fr);
    gap: 1.3rem;
    align-items: start;
}

.workspace-heading,
.workspace-meta {
    display: grid;
    gap: 0.85rem;
    align-content: start;
}

.workspace-copy {
    display: grid;
    gap: 0.75rem;
    max-width: 56rem;
}

.workspace-copy h1,
.workspace-copy .hero-subtitle {
    margin: 0;
}

.workspace-copy h1 {
    font-size: clamp(2.3rem, 4vw, 3.7rem);
    line-height: 1.03;
    letter-spacing: -0.04em;
}

.workspace-plan-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.workspace-heading .breadcrumb-link,
.workspace-heading .hero-badge {
    margin-bottom: 0;
}

/* ── Hero ── */

.app-hero {
    position: relative;
    padding: 3.75rem 0 2.25rem;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    pointer-events: none;
}

.hero-grid {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.04) 1px, transparent 1px);
    background-size: 44px 44px;
    mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.95), transparent);
}

.hero-glow {
    position: absolute;
    border-radius: 999px;
    filter: blur(90px);
}

.hero-glow-a {
    width: 26rem;
    height: 26rem;
    top: -4rem;
    left: -4rem;
    background: rgba(79, 70, 229, 0.28);
}

.hero-glow-b {
    width: 22rem;
    height: 22rem;
    right: 4rem;
    top: 1rem;
    background: rgba(167, 139, 250, 0.24);
}

.app-hero-shell {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: minmax(0, 1.35fr) minmax(290px, 0.75fr);
    gap: 1.3rem;
    align-items: start;
}

.breadcrumb-link,
.hero-badge,
.usage-pill,
.meta-pill,
.plan-chip,
.info-chip,
.summary-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    width: fit-content;
    padding: 0.55rem 0.95rem;
    border-radius: var(--radius-full);
    background: var(--surface-glass);
    border: 1px solid var(--border);
    backdrop-filter: blur(10px);
}

.breadcrumb-link {
    margin-bottom: 1rem;
    color: var(--text-secondary);
    transition: color 0.15s ease, background-color 0.15s ease;
}

.breadcrumb-link:hover {
    color: var(--text-primary);
    background: var(--surface-glass-hover);
}

.hero-badge {
    margin-bottom: 1rem;
    color: var(--accent-soft);
    font-weight: 700;
}

.hero-copy h1 {
    margin: 0 0 1rem;
    font-size: clamp(2.7rem, 5.8vw, 4.5rem);
    line-height: 1.03;
    letter-spacing: -0.04em;
}

.hero-subtitle,
.panel-copy,
.field-help,
.plan-note-item span,
.question-source,
.shortcut-strip,
.subpanel-header p,
.recent-deck-time,
.session-status,
.stat-label,
.summary-stat span {
    color: var(--text-secondary);
}

.hero-subtitle {
    max-width: 54rem;
    font-size: 1.06rem;
}

.hero-actions,
.hero-auth-actions,
.lock-actions,
.summary-actions {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.hero-actions {
    margin: 1.4rem 0 1.1rem;
}

.hero-trust-strip {
    display: flex;
    flex-wrap: wrap;
    gap: 0.85rem;
    color: var(--text-tertiary);
}

.hero-trust-strip span {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
}

.hero-panel {
    display: grid;
    gap: 0.9rem;
}

.hero-mini-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0.75rem;
}

.metric-card,
.glass-panel,
.glass-subpanel,
.stat-card,
.session-summary,
.recent-deck-card {
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.03));
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(16px);
}

.metric-card {
    padding: 1rem;
    border-radius: var(--radius-lg);
}

.metric-card strong {
    display: block;
    font-size: 1.45rem;
}

.metric-card span {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.hero-auth-card {
    padding: 1rem 1.1rem;
    border-radius: var(--radius-lg);
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border);
}

.hero-auth-card p {
    margin: 0 0 1rem;
    color: var(--text-secondary);
}

/* ── Buttons ── */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.55rem;
    padding: 0.95rem 1.2rem;
    border-radius: 0.95rem;
    border: 1px solid transparent;
    font-weight: 700;
    line-height: 1.4;
    cursor: pointer;
    transition: transform 0.15s ease, box-shadow 0.15s ease, background-color 0.15s ease, border-color 0.15s ease;
}

.btn:hover:not(:disabled) {
    transform: translateY(-1px);
}

.btn:disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: #fff;
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover:not(:disabled) {
    box-shadow: 0 16px 38px rgba(79, 70, 229, 0.3);
}

.btn-secondary {
    background: var(--surface-glass);
    color: var(--text-primary);
    border-color: var(--border);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--surface-glass-hover);
    border-color: var(--border-strong);
}

.btn-large {
    width: 100%;
}

.btn-small,
.btn-compact {
    padding: 0.7rem 0.95rem;
    font-size: 0.9rem;
}

.btn-full {
    width: 100%;
}

.btn.is-hidden,
.quiz-stage.is-hidden {
    display: none;
}

/* ── App Grid ── */

.study-shell {
    padding: 0 0 3rem;
}

.app-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.25rem;
    align-items: start;
    max-width: 960px;
    margin: 0 auto;
}

.glass-panel {
    position: relative;
    border-radius: var(--radius-2xl);
    padding: 1.3rem;
    overflow: hidden;
}

.glass-panel::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.05), transparent 36%);
    pointer-events: none;
}

.session-panel,
.builder-form,
.library-panel {
    position: relative;
    z-index: 1;
}

/* ── Drawer overlay ── */
.drawer-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
    backdrop-filter: blur(4px);
    z-index: 1100;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.drawer-overlay.is-open {
    opacity: 1;
    visibility: visible;
}

.builder-drawer {
    position: fixed;
    top: 0;
    right: 0;
    width: min(480px, 92vw);
    height: 100vh;
    z-index: 1101;
    background: var(--bg-primary);
    border-left: 1px solid var(--border);
    box-shadow: -8px 0 40px rgba(0, 0, 0, 0.4);
    display: flex;
    flex-direction: column;
    transform: translateX(100%);
    transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1);
}

.builder-drawer.is-open {
    transform: translateX(0);
}

.drawer-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.1rem 1.3rem;
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
}

.drawer-header h2 {
    margin: 0;
    font-size: 1.15rem;
    line-height: 1.2;
}

.drawer-close {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.2rem;
    height: 2.2rem;
    border: 1px solid var(--border);
    border-radius: 0.6rem;
    background: rgba(255, 255, 255, 0.04);
    color: var(--text-secondary);
    font-size: 1.1rem;
    cursor: pointer;
    transition: background 0.15s ease, color 0.15s ease;
}

.drawer-close:hover {
    background: var(--surface-glass-hover);
    color: var(--text-primary);
}

.drawer-body {
    flex: 1;
    overflow-y: auto;
    padding: 1.3rem;
    overscroll-behavior: contain;
}

.session-toolbar {
    display: flex;
    gap: 0.65rem;
    margin-bottom: 1.1rem;
    flex-wrap: wrap;
}

/* ── Panel Headers ── */

.panel-header,
.subpanel-header,
.step-header,
.recent-deck-head,
.progress-copy,
.summary-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 0.9rem;
}

.panel-header {
    margin-bottom: 1.1rem;
}

.panel-kicker {
    display: inline-block;
    margin-bottom: 0.35rem;
    color: var(--accent-soft);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.panel-header h2,
.step-header h3,
.subpanel-header h3,
.summary-header h3 {
    margin: 0;
    line-height: 1.15;
}

.panel-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.55rem;
    justify-content: flex-end;
}

.plan-chip,
.usage-pill,
.summary-badge {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.plan-chip {
    align-self: start;
}

/* ── Library ── */

.library-panel {
    border-radius: var(--radius-xl);
    padding: 1rem;
    margin-bottom: 1rem;
}

.library-empty {
    padding: 1rem;
    border-radius: 1rem;
    border: 1px dashed var(--border);
    background: rgba(255, 255, 255, 0.02);
    color: var(--text-secondary);
    font-size: 0.94rem;
}

.recent-decks {
    display: grid;
    gap: 0.75rem;
    max-height: 34rem;
    overflow-y: auto;
    padding-right: 0.2rem;
    overscroll-behavior: contain;
}

.recent-deck-card {
    padding: 0.95rem;
    border-radius: 1rem;
}

.recent-deck-card.is-current {
    border-color: rgba(124, 58, 237, 0.38);
    box-shadow: 0 0 0 1px rgba(124, 58, 237, 0.14), var(--shadow-sm);
}

.recent-deck-head strong {
    display: block;
    line-height: 1.25;
}

.recent-deck-head small {
    display: block;
    color: var(--text-secondary);
    margin-top: 0.18rem;
}

.recent-status {
    display: inline-flex;
    align-items: center;
    padding: 0.35rem 0.6rem;
    border-radius: var(--radius-full);
    background: rgba(167, 139, 250, 0.12);
    border: 1px solid rgba(167, 139, 250, 0.18);
    color: var(--accent-soft);
    font-size: 0.78rem;
    font-weight: 700;
    white-space: nowrap;
}

.recent-deck-stats {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem;
    color: var(--text-secondary);
    font-size: 0.88rem;
    margin: 0.75rem 0 0.45rem;
}

.recent-deck-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.55rem;
    margin-top: 0.75rem;
}

/* ── Builder ── */

.builder-form {
    display: grid;
    gap: 1rem;
}

.builder-step {
    padding: 1rem;
    border-radius: var(--radius-xl);
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.03);
    display: grid;
    gap: 0.9rem;
}

.step-index {
    flex: 0 0 auto;
    width: 2rem;
    height: 2rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 999px;
    background: rgba(124, 58, 237, 0.14);
    color: var(--accent-soft);
    font-weight: 800;
}

.step-header p {
    margin: 0.25rem 0 0;
    color: var(--text-secondary);
}

/* ── Fields ── */

.field-group {
    display: grid;
    gap: 0.55rem;
}

.field-grid {
    display: grid;
    gap: 0.9rem;
}

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

.field-group-wide {
    grid-column: span 2;
}

.field-label {
    font-weight: 700;
    font-size: 0.94rem;
}

.field-input,
.field-select,
.field-textarea {
    width: 100%;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border);
    color: var(--text-primary);
    border-radius: 0.95rem;
    padding: 0.9rem 1rem;
    transition: border-color 0.15s ease, background-color 0.15s ease, box-shadow 0.15s ease;
}

.field-select option {
    color: #111827;
}

.field-textarea {
    resize: vertical;
    min-height: 7rem;
}

.format-grid,
.choice-grid,
.selected-files,
.tag-list,
.summary-stats,
.builder-actions,
.plan-note,
.stats-grid,
.session-bottom-grid,
.trophy-grid {
    display: grid;
    gap: 0.75rem;
}

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

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

.choice-card {
    cursor: pointer;
}

.choice-card input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.choice-body {
    display: flex;
    align-items: flex-start;
    gap: 0.85rem;
    padding: 0.95rem 1rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.03);
    transition: transform 0.15s ease, border-color 0.15s ease, background-color 0.15s ease, box-shadow 0.15s ease;
}

.choice-body strong {
    display: block;
}

.choice-body small {
    color: var(--text-secondary);
}

.choice-card input:checked + .choice-body {
    border-color: rgba(79, 70, 229, 0.72);
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.18), rgba(124, 58, 237, 0.1));
    box-shadow: 0 10px 24px rgba(79, 70, 229, 0.12);
    transform: translateY(-1px);
}

.choice-card.is-disabled,
.choice-card input:disabled + .choice-body {
    opacity: 0.5;
    cursor: not-allowed;
}

.upload-shell {
    display: grid;
    gap: 0.7rem;
    padding: 1rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.03);
}

.file-input {
    padding: 0;
    border: 0;
    background: none;
    cursor: pointer;
}

.file-input::file-selector-button {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.6rem 1.1rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.15), rgba(124, 58, 237, 0.1));
    color: var(--accent-soft);
    font-family: var(--font);
    font-size: 0.88rem;
    font-weight: 600;
    cursor: pointer;
    margin-right: 0.75rem;
    transition: background 0.2s ease, border-color 0.2s ease;
}

.file-input::file-selector-button:hover {
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.25), rgba(124, 58, 237, 0.18));
    border-color: var(--border-strong);
}

.file-input::-webkit-file-upload-button {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.6rem 1.1rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.15), rgba(124, 58, 237, 0.1));
    color: var(--accent-soft);
    font-family: var(--font);
    font-size: 0.88rem;
    font-weight: 600;
    cursor: pointer;
    margin-right: 0.75rem;
    transition: background 0.2s ease, border-color 0.2s ease;
}

.file-input::-webkit-file-upload-button:hover {
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.25), rgba(124, 58, 237, 0.18));
    border-color: var(--border-strong);
}

.upload-meta {
    display: grid;
    gap: 0.3rem;
    color: var(--text-secondary);
    font-size: 0.92rem;
}

.upload-meta span {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
}

.selected-files {
    grid-template-columns: repeat(auto-fit, minmax(140px, max-content));
}

.file-chip {
    display: inline-flex;
    align-items: center;
    gap: 0.45rem;
    padding: 0.45rem 0.75rem;
    border-radius: var(--radius-full);
    background: rgba(167, 139, 250, 0.12);
    color: #ede9fe;
    font-size: 0.88rem;
}

.research-source-section.is-hidden {
    display: none;
}

.research-source-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 0.85rem;
}

.research-source-header .field-help {
    margin: 0.35rem 0 0;
}

.research-source-limit {
    display: inline-flex;
    align-items: center;
    padding: 0.45rem 0.75rem;
    border-radius: var(--radius-full);
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.04);
    color: var(--text-secondary);
    font-size: 0.88rem;
    white-space: nowrap;
}

.research-source-list {
    display: grid;
    gap: 0.75rem;
}

.research-source-card {
    display: grid;
    gap: 0.6rem;
    padding: 0.95rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.03);
}

.research-source-controls {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 0.75rem;
    align-items: center;
}

.research-fetch-btn {
    min-width: 7.5rem;
}

.research-source-status {
    font-size: 0.92rem;
    color: var(--text-secondary);
}

.research-source-status.is-success {
    color: #bfdbfe;
}

.research-source-status.is-error {
    color: #fecaca;
}

.research-source-status.is-loading {
    color: #ddd6fe;
}

.research-source-status.is-stale {
    color: #fde68a;
}

.advanced-options {
    border: 1px solid var(--border);
    border-radius: 1rem;
    background: rgba(255, 255, 255, 0.025);
}

.advanced-options summary {
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.95rem 1rem;
    cursor: pointer;
    font-weight: 700;
}

.advanced-options summary::-webkit-details-marker {
    display: none;
}

.advanced-options summary small {
    color: var(--text-secondary);
    font-weight: 500;
}

.advanced-options[open] summary {
    border-bottom: 1px solid var(--border);
}

.advanced-options-body {
    padding: 1rem;
    display: grid;
    gap: 1rem;
}

.builder-alert {
    padding: 0.95rem 1rem;
    border-radius: 1rem;
    border: 1px solid rgba(239, 68, 68, 0.25);
    background: rgba(239, 68, 68, 0.12);
    color: #fecaca;
}

.builder-alert.is-hidden,
.session-summary.is-hidden {
    display: none;
}

.plan-note {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

.plan-note-item {
    padding: 0.9rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.025);
}

.plan-note-item strong {
    display: block;
    margin-bottom: 0.2rem;
}

.panel-lock {
    position: absolute;
    inset: 1rem;
    z-index: 4;
    display: grid;
    place-items: center;
    gap: 0.8rem;
    text-align: center;
    background: rgba(13, 12, 29, 0.76);
    backdrop-filter: blur(18px);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
}

.lock-badge {
    width: 3rem;
    height: 3rem;
    display: grid;
    place-items: center;
    border-radius: 1rem;
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.22), rgba(124, 58, 237, 0.18));
    color: var(--accent-soft);
}

/* ── Session Panel ── */

.overview-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 0.85rem;
    margin-bottom: 1rem;
    align-items: start;
}

.overview-card {
    padding: 1rem 1.1rem;
    border-radius: 1rem;
    background: rgba(255, 255, 255, 0.035);
    border: 1px solid var(--border);
}

.overview-card p {
    margin: 0.6rem 0 0;
    color: var(--text-secondary);
}

.overview-aside {
    display: grid;
    gap: 0.6rem;
}

.meta-pill.emphasis {
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.16), rgba(124, 58, 237, 0.1));
}

.stats-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    margin-bottom: 1rem;
}

.stat-card {
    padding: 1rem;
    border-radius: 1rem;
}

.stat-card strong {
    font-size: 1.45rem;
}

.stat-card-timer strong {
    font-variant-numeric: tabular-nums;
}

.coach-banner {
    padding: 1rem 1.1rem;
    border-radius: 1rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.18), rgba(124, 58, 237, 0.1));
    border: 1px solid rgba(124, 58, 237, 0.25);
    color: #e0e7ff;
}

.progress-shell {
    margin-bottom: 1rem;
}

.progress-copy {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0.45rem;
}

.progress-bar {
    width: 100%;
    height: 0.65rem;
    border-radius: var(--radius-full);
    background: rgba(255, 255, 255, 0.06);
    overflow: hidden;
}

.progress-bar span {
    display: block;
    width: 0%;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, var(--accent), var(--primary));
    transition: width 0.3s ease;
}

/* ── Session Summary ── */

.session-summary {
    padding: 1rem 1.1rem;
    border-radius: 1.1rem;
    margin-bottom: 1rem;
}

.summary-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    margin: 0.9rem 0;
}

.summary-stat {
    padding: 0.85rem;
    border-radius: 0.95rem;
    background: rgba(255, 255, 255, 0.045);
    border: 1px solid var(--border);
}

.summary-stat strong {
    display: block;
    margin-top: 0.15rem;
    font-size: 1.15rem;
}

.summary-review {
    display: grid;
    gap: 0.65rem;
    margin-top: 1rem;
}

.review-item {
    padding: 1rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.03);
    display: grid;
    gap: 0.5rem;
}

.review-item.is-correct {
    border-color: rgba(16, 185, 129, 0.3);
}

.review-item.is-wrong {
    border-color: rgba(239, 68, 68, 0.3);
}

.review-item-header {
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

.review-icon {
    flex: 0 0 auto;
    width: 1.6rem;
    height: 1.6rem;
    display: grid;
    place-items: center;
    border-radius: var(--radius-full);
    font-size: 0.8rem;
}

.review-item.is-correct .review-icon {
    background: rgba(16, 185, 129, 0.18);
    color: var(--success);
}

.review-item.is-wrong .review-icon {
    background: rgba(239, 68, 68, 0.18);
    color: var(--danger);
}

.review-item-question {
    font-weight: 600;
    line-height: 1.3;
}

.review-answer-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    font-size: 0.92rem;
}

.review-your-answer {
    padding: 0.35rem 0.7rem;
    border-radius: var(--radius-full);
    font-weight: 600;
}

.review-item.is-correct .review-your-answer {
    background: rgba(16, 185, 129, 0.12);
    color: var(--success);
}

.review-item.is-wrong .review-your-answer {
    background: rgba(239, 68, 68, 0.12);
    color: var(--danger);
}

.review-correct-answer {
    padding: 0.35rem 0.7rem;
    border-radius: var(--radius-full);
    background: rgba(16, 185, 129, 0.12);
    color: var(--success);
    font-weight: 600;
}

.review-explanation {
    color: var(--text-secondary);
    font-size: 0.92rem;
    line-height: 1.5;
}

/* ── Quiz Stage ── */

.quiz-stage {
    display: grid;
    gap: 0.9rem;
    margin-bottom: 1rem;
}

.question-card {
    padding: 1.35rem;
    border-radius: 1.35rem;
    border: 1px solid var(--border);
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.03)),
        radial-gradient(circle at top right, rgba(167, 139, 250, 0.14), transparent 34%);
    box-shadow: var(--shadow-md);
    display: grid;
    gap: 1rem;
}

.question-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.question-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.4rem 0.85rem;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.22), rgba(124, 58, 237, 0.18));
    color: var(--accent-soft);
    font-weight: 800;
    font-size: 0.9rem;
}

.question-meta {
    display: flex;
    align-items: center;
    gap: 0.55rem;
    flex-wrap: wrap;
}

.question-text {
    margin: 0;
    font-size: clamp(1.25rem, 2.2vw, 1.65rem);
    line-height: 1.25;
}

.face-label {
    display: inline-flex;
    width: fit-content;
    padding: 0.35rem 0.65rem;
    border-radius: var(--radius-full);
    background: rgba(255, 255, 255, 0.06);
    color: var(--text-secondary);
    font-size: 0.82rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

/* ── Options ── */

.options-grid {
    display: grid;
    gap: 0.65rem;
}

.option-btn {
    display: flex;
    align-items: center;
    gap: 0.85rem;
    width: 100%;
    padding: 1rem 1.1rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.03);
    color: var(--text-primary);
    text-align: left;
    cursor: pointer;
    transition: transform 0.15s ease, border-color 0.15s ease, background-color 0.15s ease, box-shadow 0.15s ease;
}

.option-btn:hover:not(:disabled):not(.is-locked) {
    transform: translateY(-1px);
    border-color: rgba(79, 70, 229, 0.5);
    background: rgba(79, 70, 229, 0.08);
}

.option-btn:disabled {
    cursor: default;
}

.option-btn.is-locked {
    cursor: default;
}

.option-key {
    flex: 0 0 auto;
    width: 2.2rem;
    height: 2.2rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 0.7rem;
    background: rgba(255, 255, 255, 0.06);
    font-weight: 800;
    font-size: 0.92rem;
    transition: background-color 0.15s ease, color 0.15s ease;
}

.option-text {
    flex: 1;
    line-height: 1.4;
}

.option-btn.is-selected {
    border-color: rgba(79, 70, 229, 0.72);
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.18), rgba(124, 58, 237, 0.1));
    box-shadow: 0 10px 24px rgba(79, 70, 229, 0.12);
}

.option-btn.is-selected .option-key {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: #fff;
}

.option-btn.is-correct {
    border-color: rgba(16, 185, 129, 0.65);
    background: rgba(16, 185, 129, 0.12);
}

.option-btn.is-correct .option-key {
    background: var(--success);
    color: #fff;
}

.option-btn.is-wrong {
    border-color: rgba(239, 68, 68, 0.55);
    background: rgba(239, 68, 68, 0.1);
}

.option-btn.is-wrong .option-key {
    background: var(--danger);
    color: #fff;
}

.option-btn.is-dimmed {
    opacity: 0.5;
}

/* ── Explanation ── */

.explanation-card {
    padding: 1rem;
    border-radius: 1rem;
    background: rgba(16, 185, 129, 0.08);
    border: 1px solid rgba(16, 185, 129, 0.2);
    display: grid;
    gap: 0.55rem;
}

.explanation-card.is-hidden {
    display: none;
}

.explanation-header {
    display: flex;
    align-items: center;
    gap: 0.55rem;
    color: var(--success);
    font-size: 0.92rem;
}

.explanation-card p {
    margin: 0;
    color: var(--text-secondary);
    line-height: 1.55;
}

.card-source-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem;
    align-items: center;
}

.stage-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem;
    align-items: center;
}

.info-chip {
    color: var(--text-secondary);
    font-size: 0.88rem;
}

.tag-list {
    grid-template-columns: repeat(auto-fit, minmax(90px, max-content));
}

.tag-chip {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.35rem 0.7rem;
    border-radius: var(--radius-full);
    background: rgba(167, 139, 250, 0.12);
    border: 1px solid rgba(167, 139, 250, 0.16);
    color: var(--accent-soft);
    font-size: 0.82rem;
    white-space: nowrap;
}

.source-link,
.source-item-link {
    color: var(--accent-soft);
    text-decoration: underline;
    text-decoration-color: rgba(167, 139, 250, 0.35);
    text-underline-offset: 0.15rem;
}

.shortcut-strip {
    font-size: 0.9rem;
}

/* ── Bottom Grid ── */

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

.glass-subpanel {
    border-radius: 1.15rem;
    padding: 1rem;
}

.subpanel-header {
    margin-bottom: 0.75rem;
}

.info-list {
    display: grid;
    gap: 0.55rem;
}

.info-list li {
    position: relative;
    padding-left: 1rem;
    color: var(--text-secondary);
}

.info-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.56rem;
    width: 0.38rem;
    height: 0.38rem;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent), var(--primary));
}

.info-list li.is-empty {
    padding-left: 0;
    color: var(--text-tertiary);
}

.info-list li.is-empty::before {
    display: none;
}

.info-list.compact {
    margin-top: 0.85rem;
}

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

.trophy-card {
    display: grid;
    gap: 0.3rem;
    padding: 0.9rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    background: rgba(255, 255, 255, 0.03);
}

.trophy-card.unlocked {
    border-color: rgba(250, 204, 21, 0.38);
    background: linear-gradient(135deg, rgba(250, 204, 21, 0.12), rgba(79, 70, 229, 0.12));
}

.trophy-card i {
    color: #facc15;
}

.trophy-card small {
    color: var(--text-secondary);
}

/* ── Timer warning ── */

.stat-card-timer.is-warning strong {
    color: var(--warning);
}

.stat-card-timer.is-danger strong {
    color: var(--danger);
    animation: timer-pulse 1s ease-in-out infinite;
}

@keyframes timer-pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* ── Focus states ── */

.field-input:focus,
.field-select:focus,
.field-textarea:focus,
.btn:focus-visible,
.option-btn:focus-visible,
.nav-link:focus-visible,
.nav-dropdown-item:focus-visible,
.mobile-menu-button:focus-visible,
.mobile-submenu-toggle:focus-visible,
.source-link:focus-visible,
.source-item-link:focus-visible {
    outline: none;
    border-color: rgba(167, 139, 250, 0.55);
    box-shadow: 0 0 0 4px rgba(167, 139, 250, 0.14);
}

.choice-card input:focus-visible + .choice-body {
    outline: 3px solid rgba(167, 139, 250, 0.22);
    outline-offset: 3px;
}

/* ── Responsive ── */

@media (max-width: 1200px) {
    .app-hero-shell,
    .workspace-header-shell {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 900px) {
    .choice-grid,
    .source-grid,
    .field-grid-2,
    .plan-note,
    .stats-grid,
    .summary-stats,
    .session-bottom-grid,
    .trophy-grid,
    .hero-mini-grid {
        grid-template-columns: 1fr;
    }

    .field-group-wide {
        grid-column: auto;
    }

    .panel-header,
    .subpanel-header,
    .step-header,
    .progress-copy,
    .summary-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .panel-actions {
        justify-content: flex-start;
    }

    .overview-grid {
        grid-template-columns: 1fr;
    }

    .research-source-header,
    .research-source-controls {
        grid-template-columns: 1fr;
        display: grid;
    }
}

@media (max-width: 859px) {
    .nav-links,
    .auth-buttons {
        display: none;
    }

    .mobile-menu-button {
        display: block;
        margin-left: auto;
    }

    .mobile-menu {
        top: 3.5rem;
        max-height: calc(100vh - 3.5rem);
    }

    .nav-logo-img {
        height: 64px;
    }
}

@media (min-width: 860px) {
    .nav-links,
    .auth-buttons {
        display: flex;
    }

    .mobile-menu-button {
        display: none;
    }

    .mobile-menu {
        display: none !important;
    }

    .nav-links {
        gap: 0.5rem;
        align-items: center;
        margin-left: 1rem;
        margin-right: auto;
    }

    .auth-buttons {
        gap: 0.5rem;
        align-items: center;
        margin-left: 1rem;
    }

    .auth-buttons-mobile {
        display: none;
    }
}

@media (max-width: 640px) {
    .section-shell,
    .study-shell {
        width: min(100%, calc(100% - 1rem));
    }

    .workspace-header {
        padding-top: 1rem;
    }

    .hero-actions,
    .hero-auth-actions,
    .lock-actions,
    .stage-actions,
    .summary-actions,
    .recent-deck-actions {
        flex-direction: column;
        width: 100%;
    }

    .hero-actions .btn,
    .hero-auth-actions .btn,
    .lock-actions .btn,
    .stage-actions .btn,
    .summary-actions .btn,
    .recent-deck-actions .btn {
        width: 100%;
    }
}

/* ── Cookie consent (shared) ── */

.cookie-consent-banner {
    position: fixed;
    bottom: 1rem;
    left: 50%;
    transform: translateX(-50%);
    z-index: 9999;
    max-width: 520px;
    width: calc(100% - 2rem);
    padding: 1.25rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(16px);
    box-shadow: var(--shadow-lg);
}

/* ── Footer (shared) ── */

.footer-container {
    background: var(--bg-primary);
    border-top: 1px solid var(--border-glass);
    padding: 2rem 1rem;
    margin-top: 2rem;
}

.footer-content {
    max-width: 1280px;
    margin: 0 auto;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 2rem;
}

.footer-column h3 {
    margin: 0 0 0.75rem;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-secondary);
}

.footer-column a {
    display: block;
    padding: 0.3rem 0;
    color: var(--text-tertiary);
    font-size: 0.9rem;
    transition: color 0.2s;
}

.footer-column a:hover {
    color: var(--text-primary);
}

.footer-bottom {
    margin-top: 2rem;
    padding-top: 1.25rem;
    border-top: 1px solid var(--border-glass);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    color: var(--text-tertiary);
    font-size: 0.85rem;
}

.footer-bottom-links {
    display: flex;
    gap: 1.25rem;
}

.footer-bottom-links a {
    color: var(--text-tertiary);
    font-size: 0.85rem;
}

.footer-bottom-links a:hover {
    color: var(--text-primary);
}