:root {
    --bg-body:     #0a0a12;
    --bg-card:     #13131f;
    --bg-card-h:   #1a1a2e;
    --accent:      #7c3aed;
    --accent-h:    #6d28d9;
    --accent-glow: rgba(124, 58, 237, 0.25);
    --success:     #10b981;
    --danger:      #ef4444;
    --warning:     #f59e0b;
    --text:        #e2e8f0;
    --text-muted:  #94a3b8;
    --border:      #2a2a45;
    --nav-bg:      #07070e;
}

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

body {
    background: var(--bg-body);
    color: var(--text);
    font-family: 'Segoe UI', system-ui, sans-serif;
    min-height: 100vh;
    line-height: 1.6;
}

/* ── NAVBAR ─────────────────────────────── */
.navbar {
    background: var(--nav-bg) !important;
    border-bottom: 1px solid var(--border);
    padding: .75rem 1.5rem;
    box-shadow: 0 2px 20px rgba(124,58,237,.08);
}

.navbar-brand {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--accent) !important;
    letter-spacing: -.5px;
}

.nav-link {
    color: var(--text-muted) !important;
    font-weight: 500;
    padding: .45rem .75rem !important;
    border-radius: .375rem;
    transition: color .2s, background .2s;
}

.nav-link:hover { color: var(--text) !important; background: rgba(255,255,255,.05); }
.navbar-toggler { background: none !important; box-shadow: none !important; }

/* ── BUTTONS ─────────────────────────────── */
.btn-primary {
    background: var(--accent);
    border-color: var(--accent);
    font-weight: 600;
    transition: all .2s;
}
.btn-primary:hover, .btn-primary:focus {
    background: var(--accent-h);
    border-color: var(--accent-h);
    box-shadow: 0 4px 18px var(--accent-glow);
    transform: translateY(-1px);
}

.btn-outline-primary {
    color: var(--accent);
    border-color: var(--accent);
}
.btn-outline-primary:hover {
    background: var(--accent);
    border-color: var(--accent);
    transform: translateY(-1px);
}

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

.btn-outline-danger {
    color: var(--danger);
    border-color: var(--danger);
}
.btn-outline-danger:hover {
    background: var(--danger);
    border-color: var(--danger);
}

.btn-outline-light {
    color: var(--text);
    border-color: var(--border);
}
.btn-outline-light:hover {
    background: rgba(255,255,255,.08);
    color: var(--text);
    border-color: var(--border);
}

/* ── CARDS ─────────────────────────────── */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 1rem;
    transition: transform .2s, box-shadow .2s;
}

.card-header {
    background: rgba(124,58,237,.08);
    border-bottom: 1px solid var(--border);
    font-weight: 600;
    padding: .9rem 1.25rem;
    border-radius: 1rem 1rem 0 0 !important;
}

/* ── FORMS ─────────────────────────────── */
.form-control, .form-select {
    background: #181825;
    border: 1px solid var(--border);
    color: var(--text);
    border-radius: .5rem;
    padding: .65rem 1rem;
    transition: border-color .2s, box-shadow .2s;
}
.form-control:focus, .form-select:focus {
    background: #181825;
    border-color: var(--accent);
    color: var(--text);
    box-shadow: 0 0 0 3px var(--accent-glow);
}
.form-control::placeholder { color: var(--text-muted); }

.form-select option { background: #181825; color: var(--text); }

.form-label {
    font-size: .8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: .5px;
    color: var(--text-muted);
    margin-bottom: .4rem;
}

.form-range { accent-color: var(--accent); cursor: pointer; }

/* ── NAV TABS ─────────────────────────── */
.nav-tabs { border-bottom: 1px solid var(--border); }
.nav-tabs .nav-link {
    color: var(--text-muted) !important;
    border: none !important;
    background: transparent !important;
    border-radius: 0 !important;
    padding: .75rem 1.5rem !important;
    font-weight: 600;
}
.nav-tabs .nav-link.active {
    color: var(--accent) !important;
    border-bottom: 2px solid var(--accent) !important;
}

/* ── STAT CARDS ──────────────────────── */
.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 1rem;
    padding: 1.5rem;
    text-align: center;
    transition: all .2s;
}
.stat-card:hover {
    border-color: var(--accent);
    box-shadow: 0 0 20px var(--accent-glow);
    transform: translateY(-3px);
}
.stat-number { font-size: 2.4rem; font-weight: 800; line-height: 1.1; margin-bottom: .2rem; }
.stat-label  { font-size: .75rem; text-transform: uppercase; letter-spacing: 1px; color: var(--text-muted); }

/* ── HERO ─────────────────────────────── */
.hero {
    background: linear-gradient(135deg, #0a0a12 0%, #16003a 50%, #0a0a12 100%);
    padding: 5rem 0 4rem;
    position: relative;
    overflow: hidden;
}
.hero::before {
    content: '';
    position: absolute;
    width: 600px; height: 600px;
    background: radial-gradient(circle, rgba(124,58,237,.12) 0%, transparent 70%);
    top: -150px; right: -100px;
    border-radius: 50%;
    pointer-events: none;
}
.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #fff 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero-subtitle { font-size: 1.15rem; color: var(--text-muted); margin-bottom: 2rem; max-width: 500px; }

/* ── PROGRESS ─────────────────────────── */
.progress { background: var(--border); border-radius: 1rem; }
.progress-bar {
    background: linear-gradient(90deg, var(--accent), #4f46e5);
    border-radius: 1rem;
    transition: width .4s ease;
}

/* ── AVATAR ───────────────────────────── */
.avatar {
    width: 80px; height: 80px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent), #4f46e5);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: .75rem;
}

/* ── QUESTION CARD ────────────────────── */
.question-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 1.25rem;
    padding: 2rem;
    margin-bottom: 1.25rem;
}
.question-text { font-size: 1.25rem; font-weight: 600; line-height: 1.6; }

/* ── ANSWER BUTTONS ───────────────────── */
.answer-btn {
    display: block;
    width: 100%;
    background: #181825;
    border: 2px solid var(--border);
    color: var(--text);
    border-radius: .75rem;
    padding: .9rem 1.25rem;
    font-size: 1rem;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
    transition: all .18s;
    margin-bottom: .65rem;
}
.answer-btn:hover:not(:disabled) {
    border-color: var(--accent);
    background: rgba(124,58,237,.08);
    transform: translateX(4px);
}
.answer-btn:disabled { cursor: not-allowed; }
.answer-btn.correct  { border-color: var(--success) !important; background: rgba(16,185,129,.12) !important; color: var(--success) !important; }
.answer-btn.wrong    { border-color: var(--danger)  !important; background: rgba(239,68,68,.12)  !important; color: var(--danger)  !important; }

/* ── FEEDBACK BANNER ──────────────────── */
.feedback-banner {
    padding: .9rem 1.25rem;
    border-radius: .75rem;
    margin-bottom: 1rem;
    display: none;
    font-weight: 600;
}
.feedback-banner.correct { background: rgba(16,185,129,.12); border: 1px solid var(--success); color: var(--success); }
.feedback-banner.wrong   { background: rgba(239,68,68,.12);  border: 1px solid var(--danger);  color: var(--danger); }

/* ── RESULTS ──────────────────────────── */
.results-card {
    background: linear-gradient(135deg, var(--bg-card) 0%, rgba(124,58,237,.06) 100%);
    border: 1px solid var(--accent);
    border-radius: 1.5rem;
    padding: 3rem 2rem;
    text-align: center;
}
.results-score { font-size: 4.5rem; font-weight: 800; background: linear-gradient(135deg, var(--accent), #4f46e5); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }

/* ── OPTION BUTTONS (setup) ───────────── */
.option-btn {
    background: #181825;
    border: 2px solid var(--border);
    color: var(--text-muted);
    border-radius: .65rem;
    padding: .5rem 1.1rem;
    font-size: .9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all .18s;
    margin: .2rem;
}
.option-btn:hover   { border-color: var(--accent); color: var(--text); }
.option-btn.selected { border-color: var(--accent); background: rgba(124,58,237,.15); color: var(--accent); }

/* ── ALERTS ───────────────────────────── */
.alert-custom {
    background: rgba(239,68,68,.1);
    border: 1px solid var(--danger);
    color: var(--danger);
    border-radius: .65rem;
    padding: .7rem 1rem;
    font-size: .9rem;
    display: none;
}

/* ── LEADERBOARD TABLE ────────────────── */
.leaderboard-table { border-collapse: separate; border-spacing: 0 .4rem; width: 100%; }
.leaderboard-table thead th { color: var(--text-muted); font-size: .75rem; text-transform: uppercase; letter-spacing: .5px; border: none !important; background: transparent; }
.leaderboard-table tbody tr td { background: #181825; border: none; padding: .85rem 1rem; color: var(--text); vertical-align: middle; }
.leaderboard-table tbody tr td:first-child { border-radius: .65rem 0 0 .65rem; }
.leaderboard-table tbody tr td:last-child  { border-radius: 0 .65rem .65rem 0; }
.leaderboard-table tbody tr:hover td { background: var(--bg-card-h); }

.rank-badge { width: 2.2rem; height: 2.2rem; border-radius: 50%; display: inline-flex; align-items: center; justify-content: center; font-weight: 700; font-size: .85rem; }
.rank-1 { background: linear-gradient(135deg,#FFD700,#FFA500); color:#000; }
.rank-2 { background: linear-gradient(135deg,#C0C0C0,#A8A8A8); color:#000; }
.rank-3 { background: linear-gradient(135deg,#CD7F32,#8B4513); color:#fff; }
.rank-other { background: var(--border); color: var(--text-muted); }

/* ── FOOTER ───────────────────────────── */
footer {
    background: var(--nav-bg);
    border-top: 1px solid var(--border);
    padding: 1.5rem 0;
    margin-top: 4rem;
    color: var(--text-muted);
    font-size: .875rem;
    text-align: center;
}

/* ── SCROLLBAR ────────────────────────── */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg-body); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent); }

/* ── RESPONSIVE ───────────────────────── */
@media (max-width: 768px) {
    .hero-title { font-size: 2.4rem; }
    .stat-number { font-size: 1.8rem; }
    .results-score { font-size: 3rem; }
}