:root {
    --primary: #1a5276;
    --primary-dark: #123a54;
    --accent: #17a589;
    --danger: #c0392b;
    --bg: #f4f6f8;
    --card-bg: #ffffff;
    --border: #dfe4ea;
    --text: #2c3e50;
    --muted: #7f8c8d;
}
* { box-sizing: border-box; }
body {
    margin: 0;
    font-family: 'Segoe UI', Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.topbar {
    background: var(--primary-dark);
    color: #fff;
    padding: 0 20px;
}
.topbar-inner {
    max-width: 1100px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
    flex-wrap: wrap;
}
.brand { color: #fff; font-weight: 700; font-size: 1.2rem; }
.brand:hover { text-decoration: none; }
.topbar nav a {
    color: #dfe9f2;
    margin-left: 16px;
    font-size: 0.92rem;
}
.topbar nav a:hover { color: #fff; }
.user-chip {
    margin-left: 16px;
    color: #a9d4c4;
    font-size: 0.88rem;
}
.btn-link {
    background: var(--accent);
    padding: 6px 12px;
    border-radius: 4px;
    color: #fff !important;
}

.container {
    max-width: 1100px;
    margin: 24px auto;
    padding: 0 20px;
    min-height: 60vh;
}

.footer {
    text-align: center;
    color: var(--muted);
    padding: 20px;
    font-size: 0.85rem;
}

.card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 20px;
}

h1, h2, h3 { color: var(--primary-dark); }

.grid { display: grid; gap: 16px; }
.grid-2 { grid-template-columns: 1fr 1fr; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 768px) {
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}

.stat-box {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 16px;
    text-align: center;
}
.stat-box .num { font-size: 1.8rem; font-weight: 700; color: var(--primary); }
.stat-box .label { color: var(--muted); font-size: 0.85rem; }

table {
    width: 100%;
    border-collapse: collapse;
    background: #fff;
}
th, td {
    border: 1px solid var(--border);
    padding: 10px 12px;
    text-align: left;
    font-size: 0.92rem;
}
th { background: #eef2f5; }
tr:hover td { background: #fafcfd; }

.btn {
    display: inline-block;
    background: var(--primary);
    color: #fff;
    border: none;
    padding: 10px 18px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.95rem;
}
.btn:hover { background: var(--primary-dark); text-decoration: none; color: #fff; }
.btn-sm { padding: 5px 10px; font-size: 0.82rem; }
.btn-danger { background: var(--danger); }
.btn-danger:hover { background: #922b21; }
.btn-outline {
    background: transparent;
    color: var(--primary);
    border: 1px solid var(--primary);
}
.btn-outline:hover { background: var(--primary); color: #fff; }

form .field { margin-bottom: 14px; }
label { display: block; margin-bottom: 5px; font-weight: 600; font-size: 0.9rem; }
input[type=text], input[type=email], input[type=password], input[type=number],
select, textarea {
    width: 100%;
    padding: 9px 10px;
    border: 1px solid var(--border);
    border-radius: 5px;
    font-size: 0.95rem;
}
textarea { resize: vertical; min-height: 70px; }

.alert {
    padding: 12px 16px;
    border-radius: 6px;
    margin-bottom: 16px;
    font-size: 0.9rem;
}
.alert-error { background: #fdecea; color: var(--danger); border: 1px solid #f5c6cb; }
.alert-success { background: #eafaf1; color: #1e8449; border: 1px solid #c3e6cb; }

.badge {
    display: inline-block;
    padding: 3px 9px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
}
.badge-easy { background: #d5f5e3; color: #196f3d; }
.badge-medium { background: #fef9e7; color: #9a7d0a; }
.badge-hard { background: #fdedec; color: #943126; }
.badge-expert { background: #f4ecf7; color: #6c3483; }

.progress-bar {
    background: #e5e8ec;
    border-radius: 6px;
    overflow: hidden;
    height: 14px;
    margin-top: 4px;
}
.progress-bar-fill {
    background: var(--accent);
    height: 100%;
    text-align: right;
    color: transparent;
}

.exam-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--primary-dark);
    color: #fff;
    padding: 14px 20px;
    border-radius: 8px 8px 0 0;
}
.timer {
    font-weight: 700;
    font-size: 1.1rem;
    background: #123a54;
    padding: 6px 12px;
    border-radius: 5px;
}
.exam-body { background: #fff; border: 1px solid var(--border); border-top: none; padding: 24px; border-radius: 0 0 8px 8px; }
.option-row {
    display: block;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: 6px;
    margin-bottom: 8px;
    cursor: pointer;
}
.option-row:hover { background: #f4f8fa; }
.option-row input { margin-right: 10px; }

.q-nav-grid {
    display: grid;
    grid-template-columns: repeat(10, 1fr);
    gap: 6px;
    margin: 16px 0;
}
.q-nav-grid a {
    display: block;
    text-align: center;
    padding: 8px 0;
    border-radius: 4px;
    border: 1px solid var(--border);
    font-size: 0.85rem;
    color: var(--text);
}
.q-nav-grid a.answered { background: #d5f5e3; border-color: #a9dfbf; }
.q-nav-grid a.review { background: #fef9e7; border-color: #f9e79f; }
.q-nav-grid a.current { outline: 2px solid var(--primary); }

.correct-ans { color: #196f3d; font-weight: 600; }
.wrong-ans { color: var(--danger); font-weight: 600; }