:root {
    --bg-body: #0b0f19;
    --bg-surface: rgba(255,255,255,0.03);
    --bg-card: rgba(30,41,59,0.6);
    --bg-hover: rgba(255,255,255,0.06);
    --bg-selected: rgba(59,130,246,0.12);
    --border: rgba(148,163,184,0.12);
    --border-hover: #3b82f6;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent: #3b82f6;
    --accent-glow: rgba(59,130,246,0.25);
    --accent-hover: #2563eb;
    --success: #10b981;
    --success-bg: rgba(16,185,129,0.1);
    --danger: #f43f5e;
    --danger-bg: rgba(244,63,94,0.1);
    --warning: #f59e0b;
    --warning-bg: rgba(245,158,11,0.1);
    --shadow: 0 8px 32px rgba(0,0,0,0.45);
    --radius: 16px;
    --radius-sm: 10px;
}

[data-theme="light"] {
    --bg-body: #f1f5f9;
    --bg-surface: rgba(255,255,255,0.7);
    --bg-card: rgba(255,255,255,0.85);
    --bg-hover: rgba(241,245,249,0.8);
    --bg-selected: rgba(59,130,246,0.08);
    --border: rgba(148,163,184,0.25);
    --border-hover: #2563eb;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --accent: #2563eb;
    --accent-glow: rgba(37,99,235,0.2);
    --accent-hover: #1d4ed8;
    --success: #059669;
    --success-bg: rgba(16,185,129,0.08);
    --danger: #e11d48;
    --danger-bg: rgba(244,63,94,0.08);
    --warning: #d97706;
    --warning-bg: rgba(245,158,11,0.08);
    --shadow: 0 4px 24px rgba(0,0,0,0.08);
}

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

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background: var(--bg-body);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    transition: background 0.4s ease, color 0.4s ease;
    overflow-x: hidden;
}

.bg-gradient {
    position: fixed; inset: 0; z-index: -2; pointer-events: none;
    background:
        radial-gradient(ellipse 80% 50% at 20% 10%, rgba(59,130,246,0.12) 0%, transparent 60%),
        radial-gradient(ellipse 60% 40% at 80% 90%, rgba(16,185,129,0.08) 0%, transparent 55%),
        radial-gradient(ellipse 50% 50% at 50% 50%, rgba(139,92,246,0.05) 0%, transparent 50%);
}

.noise-overlay {
    position: fixed; inset: 0; z-index: -1; pointer-events: none; opacity: 0.03;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* Navbar */
.navbar {
    position: sticky; top: 0; z-index: 100;
    display: flex; align-items: center; justify-content: space-between;
    padding: 16px 24px;
    background: rgba(11,15,25,0.7);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
}
[data-theme="light"] .navbar { background: rgba(241,245,249,0.7); }

.nav-brand { display: flex; align-items: center; gap: 12px; }
.brand-icon {
    width: 36px; height: 36px; border-radius: 10px;
    background: linear-gradient(135deg, var(--accent), #6366f1);
    display: flex; align-items: center; justify-content: center;
    color: white; box-shadow: 0 4px 12px var(--accent-glow);
}
.brand-title { font-weight: 700; font-size: 1.15rem; letter-spacing: -0.3px; }

.icon-btn {
    width: 36px; height: 36px; border-radius: 10px;
    background: var(--bg-surface); border: 1px solid var(--border);
    color: var(--text-secondary); cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    transition: all 0.2s;
}
.icon-btn:hover { background: var(--bg-hover); border-color: var(--border-hover); color: var(--text-primary); }

[data-theme="dark"] .sun-icon { display: none; }
[data-theme="light"] .moon-icon { display: none; }

/* App Container */
.app-container { max-width: 920px; margin: 0 auto; padding: 32px 20px 80px; }

/* Screen transitions */
.screen { display: none; animation: fadeIn 0.4s ease; }
.screen.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }

/* Home */
.hero { text-align: center; margin-bottom: 40px; }
.hero-badge {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 6px 14px; border-radius: 999px;
    background: var(--bg-surface); border: 1px solid var(--border);
    color: var(--accent); font-size: 0.8rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px;
    margin-bottom: 16px;
}
.hero-title { font-size: clamp(1.8rem, 5vw, 2.8rem); font-weight: 800; letter-spacing: -1px; margin-bottom: 12px; line-height: 1.15; }
.hero-subtitle { font-size: 1.05rem; color: var(--text-secondary); max-width: 560px; margin: 0 auto; }

.modes-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 20px; margin-bottom: 40px; }

.mode-card {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    cursor: pointer;
    transition: all 0.3s ease;
    overflow: hidden;
}
.mode-card::before {
    content: ''; position: absolute; inset: 0; border-radius: var(--radius);
    background: linear-gradient(135deg, transparent 60%, rgba(59,130,246,0.06) 100%);
    opacity: 0; transition: opacity 0.3s;
}
.mode-card:hover::before { opacity: 1; }
.mode-card:hover { transform: translateY(-4px); border-color: var(--border-hover); box-shadow: var(--shadow); }

.mode-icon {
    width: 56px; height: 56px; border-radius: 14px;
    background: linear-gradient(135deg, var(--accent), #6366f1);
    color: white;
    display: flex; align-items: center; justify-content: center;
    margin-bottom: 18px; box-shadow: 0 8px 20px var(--accent-glow);
}
.mode-exam .mode-icon { background: linear-gradient(135deg, #f43f5e, #f59e0b); box-shadow: 0 8px 20px rgba(244,63,94,0.25); }
.mode-reference .mode-icon { background: linear-gradient(135deg, #10b981, #059669); box-shadow: 0 8px 20px rgba(16,185,129,0.25); }
.mode-mistakes .mode-icon { background: linear-gradient(135deg, #f43f5e, #f59e0b); box-shadow: 0 8px 20px rgba(244,63,94,0.25); }

.mode-title { font-size: 1.25rem; font-weight: 700; margin-bottom: 8px; }
.mode-desc { color: var(--text-secondary); font-size: 0.92rem; margin-bottom: 16px; line-height: 1.5; }
.mode-meta { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; }
.meta-tag {
    display: inline-flex; align-items: center; gap: 5px;
    padding: 5px 10px; border-radius: 6px;
    background: var(--bg-surface); border: 1px solid var(--border);
    font-size: 0.78rem; color: var(--text-secondary);
}

.mode-btn {
    width: 100%; padding: 12px; border-radius: var(--radius-sm);
    background: var(--bg-surface); border: 1px solid var(--border);
    color: var(--text-primary); font-weight: 600; font-size: 0.95rem;
    cursor: pointer; transition: all 0.2s;
}
.mode-btn-accent { background: linear-gradient(135deg, var(--accent), #6366f1); color: white; border: none; box-shadow: 0 4px 14px var(--accent-glow); }
.mode-btn-accent:hover { box-shadow: 0 6px 20px var(--accent-glow); transform: translateY(-1px); }
.mode-card:hover .mode-btn { border-color: var(--border-hover); }
.mode-card:hover .mode-btn-accent { filter: brightness(1.08); }

.stats-bar {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 12px;
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 20px;
}
.stat-item { text-align: center; }
.stat-value { display: block; font-size: 1.6rem; font-weight: 800; color: var(--accent); line-height: 1; }
.stat-label { font-size: 0.8rem; color: var(--text-secondary); margin-top: 4px; }

/* Quiz Screens */
.quiz-header, .exam-topbar {
    display: flex; align-items: center; justify-content: space-between; gap: 12px;
    margin-bottom: 24px; flex-wrap: wrap;
}
.exam-topbar { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 18px; }

.back-btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 8px 14px; border-radius: var(--radius-sm);
    background: transparent; border: 1px solid var(--border);
    color: var(--text-secondary); font-size: 0.88rem; font-weight: 500;
    cursor: pointer; transition: all 0.2s;
}
.back-btn:hover { border-color: var(--danger); color: var(--danger); background: var(--danger-bg); }

.quiz-progress { flex: 1; min-width: 180px; }
.progress-text { display: block; font-size: 0.82rem; color: var(--text-secondary); margin-bottom: 6px; }
.progress-track { height: 6px; background: var(--bg-surface); border-radius: 999px; overflow: hidden; border: 1px solid var(--border); }
.progress-fill { height: 100%; background: linear-gradient(90deg, var(--accent), #6366f1); border-radius: 999px; transition: width 0.4s ease; width: 1%; }

.exam-timer {
    font-family: 'SF Mono', monospace; font-size: 1.3rem; font-weight: 700;
    color: var(--danger); background: var(--danger-bg);
    padding: 6px 14px; border-radius: var(--radius-sm); letter-spacing: 1px;
}
.exam-timer.warning { animation: pulse 1s infinite; }
@keyframes pulse { 0%,100% { opacity: 1; } 50% { opacity: 0.6; } }

.quiz-card {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 32px; margin-bottom: 20px; box-shadow: var(--shadow);
    position: relative; overflow: hidden;
}
.quiz-card::before {
    content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px;
    background: linear-gradient(90deg, var(--accent), #6366f1); opacity: 0.6;
}

.question-counter {
    font-size: 0.75rem; font-weight: 700; color: var(--accent); text-transform: uppercase; letter-spacing: 1px;
    margin-bottom: 12px;
}
.question-text { font-size: 1.15rem; font-weight: 600; line-height: 1.55; margin-bottom: 24px; }

.options-list { display: flex; flex-direction: column; gap: 10px; margin-bottom: 24px; }
.option {
    display: flex; align-items: center; gap: 14px;
    padding: 14px 18px; border-radius: var(--radius-sm);
    background: var(--bg-surface); border: 1.5px solid var(--border);
    color: var(--text-primary); font-size: 0.97rem;
    cursor: pointer; transition: all 0.2s; user-select: none;
}
.option:hover { border-color: var(--border-hover); background: var(--bg-hover); }
.option.selected { border-color: var(--accent); background: var(--bg-selected); box-shadow: 0 0 0 3px var(--accent-glow); }
.option.correct { border-color: var(--success); background: var(--success-bg); }
.option.wrong { border-color: var(--danger); background: var(--danger-bg); }

.option-marker {
    width: 24px; height: 24px; border-radius: 50%;
    border: 2px solid var(--border); flex-shrink: 0;
    display: flex; align-items: center; justify-content: center;
    font-size: 0.7rem; font-weight: 700; color: var(--text-muted);
    transition: all 0.2s;
}
.option.selected .option-marker { border-color: var(--accent); color: var(--accent); background: var(--bg-selected); }
.option.correct .option-marker { border-color: var(--success); color: var(--success); background: var(--success-bg); }
.option.wrong .option-marker { border-color: var(--danger); color: var(--danger); background: var(--danger-bg); }

.feedback {
    display: flex; align-items: flex-start; gap: 14px;
    padding: 18px; border-radius: var(--radius-sm); margin-bottom: 20px;
    animation: fadeIn 0.3s ease;
}
.feedback.correct { background: var(--success-bg); border: 1px solid var(--success); }
.feedback.wrong { background: var(--danger-bg); border: 1px solid var(--danger); }
.feedback-icon { width: 28px; height: 28px; border-radius: 50%; flex-shrink: 0; display: flex; align-items: center; justify-content: center; font-size: 0.85rem; font-weight: 700; }
.feedback.correct .feedback-icon { background: var(--success); color: white; }
.feedback.wrong .feedback-icon { background: var(--danger); color: white; }
.feedback-title { font-weight: 700; margin-bottom: 4px; }
.feedback-answer { font-size: 0.9rem; color: var(--text-secondary); }
.feedback-answer span { font-weight: 700; color: var(--text-primary); }

.quiz-actions { display: flex; gap: 10px; flex-wrap: wrap; }
.quiz-nav { display: flex; justify-content: space-between; gap: 10px; margin-top: 10px; flex-wrap: wrap; }

/* Buttons */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 8px;
    padding: 12px 24px; border-radius: var(--radius-sm); font-weight: 600; font-size: 0.95rem;
    cursor: pointer; transition: all 0.2s; border: none;
}
.btn-primary { background: linear-gradient(135deg, var(--accent), #6366f1); color: white; box-shadow: 0 4px 14px var(--accent-glow); }
.btn-primary:hover { filter: brightness(1.08); transform: translateY(-1px); }
.btn-secondary { background: var(--bg-surface); border: 1px solid var(--border); color: var(--text-primary); }
.btn-secondary:hover { border-color: var(--border-hover); background: var(--bg-hover); }
.btn-ghost { background: transparent; border: 1px solid var(--border); color: var(--text-secondary); }
.btn-ghost:hover { border-color: var(--border-hover); color: var(--text-primary); background: var(--bg-hover); }

/* Results */
.results-hero { text-align: center; margin-bottom: 32px; }
.result-score-ring { position: relative; width: 160px; height: 160px; margin: 0 auto 20px; }
.score-ring { width: 100%; height: 100%; transform: rotate(-90deg); }
.score-ring-bg { fill: none; stroke: var(--bg-surface); stroke-width: 8; }
.score-ring-fill { fill: none; stroke: url(#scoreGradient); stroke-width: 8; stroke-linecap: round;
    stroke-dasharray: 339.292; stroke-dashoffset: 339.292; transition: stroke-dashoffset 1.2s ease;
}
.score-value { position: absolute; inset: 0; display: flex; align-items: center; justify-content: center;
    font-size: 2.2rem; font-weight: 800; color: var(--text-primary);
}
.results-title { font-size: 1.6rem; font-weight: 700; margin-bottom: 6px; }
.results-subtitle { color: var(--text-secondary); margin-bottom: 14px; }
.result-badge {
    display: inline-block; padding: 6px 16px; border-radius: 999px;
    font-size: 0.85rem; font-weight: 600;
}
.result-badge.pass { background: var(--success-bg); color: var(--success); border: 1px solid var(--success); }
.result-badge.fail { background: var(--danger-bg); color: var(--danger); border: 1px solid var(--danger); }

.results-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-bottom: 28px; }
.result-stat {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 18px; text-align: center;
}
.result-stat-icon { width: 36px; height: 36px; border-radius: 10px; margin: 0 auto 10px;
    display: flex; align-items: center; justify-content: center;
}
.result-stat-correct .result-stat-icon { background: var(--success-bg); color: var(--success); }
.result-stat-wrong .result-stat-icon { background: var(--danger-bg); color: var(--danger); }
.result-stat-empty .result-stat-icon { background: var(--warning-bg); color: var(--warning); }
.result-stat-value { font-size: 1.5rem; font-weight: 800; margin-bottom: 2px; }
.result-stat-correct .result-stat-value { color: var(--success); }
.result-stat-wrong .result-stat-value { color: var(--danger); }
.result-stat-empty .result-stat-value { color: var(--warning); }
.result-stat-label { font-size: 0.8rem; color: var(--text-secondary); }

.results-actions { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; margin-bottom: 32px; }

.review-panel { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; }
.review-title { font-size: 1.15rem; font-weight: 700; margin-bottom: 16px; }
.review-item { padding: 14px 0; border-bottom: 1px solid var(--border); }
.review-item:last-child { border-bottom: none; }
.review-q { font-weight: 600; margin-bottom: 6px; }
.review-ans { font-size: 0.88rem; }
.review-ans .correct { color: var(--success); font-weight: 600; }
.review-ans .wrong { color: var(--danger); font-weight: 600; }

/* Utilities */
.hidden { display: none !important; }

/* Reference */
.ref-search-wrap { margin-bottom: 20px; }
.ref-search {
    width: 100%; padding: 14px 18px; border-radius: var(--radius-sm);
    background: var(--bg-card); border: 1px solid var(--border);
    color: var(--text-primary); font-size: 1rem; outline: none;
    transition: border-color 0.2s;
}
.ref-search:focus { border-color: var(--accent); }
.ref-search::placeholder { color: var(--text-muted); }
.ref-item {
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-sm);
    padding: 18px; margin-bottom: 12px; transition: border-color 0.2s;
}
.ref-item:hover { border-color: var(--border-hover); }
.ref-item-header {
    display: flex; align-items: center; gap: 10px; margin-bottom: 10px;
}
.ref-item-num {
    width: 28px; height: 28px; border-radius: 6px;
    background: var(--bg-surface); border: 1px solid var(--border);
    display: flex; align-items: center; justify-content: center;
    font-size: 0.75rem; font-weight: 700; color: var(--accent); flex-shrink: 0;
}
.ref-item-q { font-weight: 600; line-height: 1.45; }
.ref-item-opts { margin-top: 10px; display: flex; flex-direction: column; gap: 6px; }
.ref-opt {
    display: flex; align-items: center; gap: 8px;
    padding: 8px 10px; border-radius: 6px; font-size: 0.9rem;
    background: var(--bg-surface); border: 1px solid var(--border);
}
.ref-opt.correct { border-color: var(--success); background: var(--success-bg); color: var(--success); font-weight: 600; }
.ref-opt-num { width: 20px; height: 20px; border-radius: 4px; background: var(--bg-hover); display: flex; align-items: center; justify-content: center; font-size: 0.7rem; font-weight: 700; flex-shrink: 0; }
.ref-opt.correct .ref-opt-num { background: var(--success); color: white; }
.ref-empty { text-align: center; color: var(--text-secondary); padding: 40px; }

/* Resume banner */
.resume-banner {
    display: flex; align-items: center; gap: 14px;
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 16px 20px; margin-bottom: 20px; cursor: pointer;
    transition: all 0.2s;
}
.resume-banner:hover { border-color: var(--accent); box-shadow: var(--shadow); transform: translateY(-2px); }
.resume-icon {
    width: 40px; height: 40px; border-radius: 10px;
    background: linear-gradient(135deg, var(--accent), #6366f1);
    color: white; display: flex; align-items: center; justify-content: center;
    flex-shrink: 0;
}
.resume-text { flex: 1; }
.resume-title { font-weight: 700; font-size: 0.95rem; }
.resume-subtitle { color: var(--text-secondary); font-size: 0.82rem; }
.resume-arrow { color: var(--accent); font-weight: 700; font-size: 1.1rem; }

/* Login */
.login-card {
    max-width: 380px; margin: 10vh auto 0; text-align: center;
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 40px 32px; box-shadow: var(--shadow);
}
.login-icon {
    width: 72px; height: 72px; border-radius: 18px;
    background: linear-gradient(135deg, var(--accent), #6366f1);
    color: white; display: flex; align-items: center; justify-content: center;
    margin: 0 auto 20px; box-shadow: 0 8px 24px var(--accent-glow);
}
.login-title { font-size: 1.5rem; font-weight: 700; margin-bottom: 6px; }
.login-subtitle { color: var(--text-secondary); font-size: 0.92rem; margin-bottom: 24px; }
.login-input {
    width: 100%; padding: 14px 16px; border-radius: var(--radius-sm);
    background: var(--bg-surface); border: 1px solid var(--border);
    color: var(--text-primary); font-size: 1rem; outline: none;
    margin-bottom: 14px; transition: border-color 0.2s;
}
.login-input:focus { border-color: var(--accent); }
.login-btn { width: 100%; }
.login-error { color: var(--danger); font-size: 0.85rem; margin-top: 10px; }

/* Dashboard */
.dashboard-bar {
    display: grid; grid-template-columns: repeat(auto-fit, minmax(110px, 1fr)); gap: 12px;
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius);
    padding: 20px; margin-bottom: 20px;
}
.dash-item { text-align: center; }
.dash-value { display: block; font-size: 1.4rem; font-weight: 800; color: var(--accent); line-height: 1; }
.dash-label { font-size: 0.75rem; color: var(--text-secondary); margin-top: 4px; }

/* History */
.history-panel { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; margin-bottom: 20px; }
.history-title { font-size: 1rem; font-weight: 700; margin-bottom: 12px; }
.history-row { display: flex; align-items: center; justify-content: space-between; padding: 10px 0; border-bottom: 1px solid var(--border); font-size: 0.9rem; }
.history-row:last-child { border-bottom: none; }
.history-date { color: var(--text-secondary); }
.history-score { font-weight: 700; }
.history-score.pass { color: var(--success); }
.history-score.fail { color: var(--danger); }

/* Question Grid */
.question-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(36px, 1fr)); gap: 6px;
    margin-bottom: 16px;
}
.qg-cell {
    aspect-ratio: 1; border-radius: 6px;
    background: var(--bg-surface); border: 1px solid var(--border);
    color: var(--text-secondary); font-size: 0.72rem; font-weight: 600;
    display: flex; align-items: center; justify-content: center;
    cursor: pointer; transition: all 0.15s; user-select: none;
}
.qg-cell:hover { border-color: var(--border-hover); color: var(--text-primary); }
.qg-cell.current { border-color: var(--accent); color: var(--accent); background: var(--bg-selected); box-shadow: 0 0 0 2px var(--accent-glow); }
.qg-cell.answered { background: var(--success-bg); border-color: var(--success); color: var(--success); }
.qg-cell.wrong { background: var(--danger-bg); border-color: var(--danger); color: var(--danger); }

/* Reference favorites */
.ref-fav-btn {
    margin-left: auto; width: 32px; height: 32px; border-radius: 8px;
    background: transparent; border: 1px solid var(--border); color: var(--text-muted);
    cursor: pointer; display: flex; align-items: center; justify-content: center;
    transition: all 0.2s; flex-shrink: 0;
}
.ref-fav-btn:hover { border-color: var(--warning); color: var(--warning); }
.ref-fav-btn.active { color: var(--warning); border-color: var(--warning); background: var(--warning-bg); }
.ref-filter-bar { display: flex; gap: 8px; margin-bottom: 14px; flex-wrap: wrap; }
.ref-filter-btn {
    padding: 6px 12px; border-radius: 6px; font-size: 0.82rem; font-weight: 500;
    background: var(--bg-surface); border: 1px solid var(--border); color: var(--text-secondary);
    cursor: pointer; transition: all 0.2s;
}
.ref-filter-btn.active { background: var(--accent); color: white; border-color: var(--accent); }

/* Settings Panel */
.settings-panel { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; margin-bottom: 20px; }
.settings-title { display: flex; align-items: center; gap: 8px; font-size: 1rem; font-weight: 700; margin-bottom: 14px; }
.settings-grid { display: flex; flex-direction: column; gap: 10px; }
.setting-item { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 10px 0; border-bottom: 1px solid var(--border); }
.setting-item:last-child { border-bottom: none; }
.setting-info { flex: 1; }
.setting-label { font-weight: 600; font-size: 0.92rem; }
.setting-desc { color: var(--text-secondary); font-size: 0.8rem; }
.setting-select { padding: 6px 10px; border-radius: 6px; background: var(--bg-surface); border: 1px solid var(--border); color: var(--text-primary); font-size: 0.9rem; }

/* Toggle Switch */
.toggle { position: relative; display: inline-block; width: 44px; height: 24px; }
.toggle input { opacity: 0; width: 0; height: 0; }
.toggle-slider { position: absolute; cursor: pointer; inset: 0; background: var(--bg-surface); border: 1px solid var(--border); border-radius: 24px; transition: .2s; }
.toggle-slider::before { position: absolute; content: ""; height: 18px; width: 18px; left: 2px; bottom: 2px; background: var(--text-muted); border-radius: 50%; transition: .2s; }
.toggle input:checked + .toggle-slider { background: var(--accent); border-color: var(--accent); }
.toggle input:checked + .toggle-slider::before { transform: translateX(20px); background: white; }

/* User Bar */
.user-bar { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.user-select { padding: 8px 12px; border-radius: 6px; background: var(--bg-surface); border: 1px solid var(--border); color: var(--text-primary); font-size: 0.9rem; }
.user-input { padding: 8px 12px; border-radius: 6px; background: var(--bg-surface); border: 1px solid var(--border); color: var(--text-primary); font-size: 0.9rem; flex: 1; min-width: 140px; }
.user-hint { color: var(--text-muted); font-size: 0.8rem; margin-top: 8px; }

/* SVG gradient for score ring */
.score-ring-defs { position: absolute; width: 0; height: 0; }

/* Custom training (по выбору) */
.mode-custom .mode-icon { background: linear-gradient(135deg, #8b5cf6, #6366f1); box-shadow: 0 8px 20px rgba(139,92,246,0.25); }

.custom-toolbar { display: flex; gap: 8px; align-items: center; margin-bottom: 14px; flex-wrap: wrap; }
.custom-counter { margin-left: auto; font-size: 0.85rem; font-weight: 600; color: var(--text-secondary); }

.custom-item {
    display: flex; align-items: center; gap: 12px;
    background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-sm);
    padding: 12px 14px; margin-bottom: 8px; cursor: pointer; transition: all 0.15s; user-select: none;
}
.custom-item:hover { border-color: var(--border-hover); }
.custom-item.selected { border-color: var(--accent); background: var(--bg-selected); }
.custom-check {
    width: 24px; height: 24px; border-radius: 6px; flex-shrink: 0;
    border: 2px solid var(--border); display: flex; align-items: center; justify-content: center;
    color: white; transition: all 0.15s;
}
.custom-item.selected .custom-check { background: var(--accent); border-color: var(--accent); }
.custom-item-num {
    min-width: 32px; height: 26px; padding: 0 6px; border-radius: 6px; flex-shrink: 0;
    background: var(--bg-surface); border: 1px solid var(--border);
    display: flex; align-items: center; justify-content: center;
    font-size: 0.72rem; font-weight: 700; color: var(--accent);
}
.custom-item-q { font-size: 0.92rem; font-weight: 500; line-height: 1.4; }

.custom-startbar {
    position: sticky; bottom: 0; z-index: 20;
    display: flex; justify-content: center;
    padding: 16px 0 8px; margin-top: 12px;
    background: linear-gradient(to top, var(--bg-body) 55%, transparent);
}
.custom-startbar .btn { min-width: 260px; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; filter: none; transform: none; box-shadow: none; }

/* ====== MOBILE RESPONSIVE ====== */
@media (max-width: 640px) {
    .app-container { padding: 16px; }
    .hero { padding: 24px 16px; }
    .hero-title { font-size: 1.5rem; }
    .hero-subtitle { font-size: 0.9rem; }
    .modes-grid { grid-template-columns: 1fr; }
    .mode-card { padding: 20px; }
    .mode-icon { width: 48px; height: 48px; }
    .mode-title { font-size: 1.1rem; }
    .mode-desc { font-size: 0.88rem; }

    .quiz-card { padding: 20px; }
    .question-text { font-size: 1.05rem; }
    .option { padding: 14px; min-height: 52px; }
    .option-marker { width: 32px; height: 32px; font-size: 0.85rem; }
    .btn { padding: 12px 18px; font-size: 0.95rem; min-height: 48px; }

    .dashboard-bar { grid-template-columns: repeat(2, 1fr); padding: 16px; }
    .dash-value { font-size: 1.2rem; }

    .quiz-nav { flex-direction: column; gap: 10px; }
    .quiz-nav .btn { width: 100%; justify-content: center; }

    .exam-topbar { flex-wrap: wrap; gap: 10px; padding: 12px 16px; }
    .exam-timer { font-size: 1.1rem; }

    .results-hero { padding: 24px 16px; }
    .score-ring { width: 140px; height: 140px; }
    .score-percent { font-size: 2rem; }
    .result-stats { grid-template-columns: 1fr; }

    .user-bar { flex-direction: column; align-items: stretch; }
    .user-input, .user-select { width: 100%; }

    .navbar { padding: 0 14px; }
    .brand-title { font-size: 0.85rem; }

    .question-grid { grid-template-columns: repeat(auto-fill, minmax(40px, 1fr)); gap: 8px; }
    .qg-cell { font-size: 0.85rem; }
}

/* Prevent text selection on options (better for mobile tapping) */
.option, .qg-cell, .btn, .mode-card, .ref-fav-btn {
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
}