/* ── General ────────────────────────────────────────── */
body {
    font-family: 'Inter', sans-serif;
    background: #f4f7fb;
    color: #1a1a2e;
    font-size: 15px;
    -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: 'Inter', sans-serif;
    font-weight: 700;
    letter-spacing: -0.3px;
}

a {
    text-decoration: none;
}

/* ── Navbar ─────────────────────────────────────────── */
.navbar {
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
}

.navbar-brand {
    font-size: 1.3rem;
    letter-spacing: 0.5px;
}

/* ── Hero ───────────────────────────────────────────── */
.hero {
    background: linear-gradient(135deg, #1a3a5c 0%, #1a6aad 100%);
    padding: 80px 0;
}

.hero h1 {
    font-size: 2.8rem;
    font-weight: 900;
    line-height: 1.2;
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }

    .hero {
        padding: 50px 0;
    }
}

/* ── Topic Cards ────────────────────────────────────── */
.topic-card {
    transition: transform 0.2s, box-shadow 0.2s;
    border-radius: 16px !important;
    overflow: hidden;
    cursor: pointer;
}

.topic-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.12) !important;
}

.topic-card .card-footer {
    border-top: 1px solid #f0f0f0 !important;
}

/* ── Badges ─────────────────────────────────────────── */
.badge {
    font-size: 0.75rem;
    padding: 6px 12px;
    border-radius: 50px;
}

/* ── Buttons ────────────────────────────────────────── */
.btn {
    border-radius: 8px !important;
    font-weight: 600;
}

.btn-warning {
    background: #e8a020;
    border-color: #e8a020;
    color: #fff;
}

.btn-warning:hover {
    background: #cf8f1a;
    border-color: #cf8f1a;
    color: #fff;
}

/* ── Forms ──────────────────────────────────────────── */
.form-control {
    border-radius: 8px !important;
    padding: 10px 14px;
    border: 1.5px solid #dde4ef;
    background: #f8fafc;
}

.form-control:focus {
    border-color: #1a6aad;
    box-shadow: 0 0 0 3px rgba(26, 106, 173, 0.1);
    background: #fff;
}

.input-group-text {
    border-radius: 8px 0 0 8px !important;
    border: 1.5px solid #dde4ef;
    border-right: none !important;
}

/* ── Cards ──────────────────────────────────────────── */
.card {
    border-radius: 16px !important;
}

/* ── Material List ──────────────────────────────────── */
.list-group-item {
    border: 1px solid #eef0f5;
    padding: 16px 20px;
    transition: background 0.15s;
}

.list-group-item:hover {
    background: #f4f7fb;
}

.list-group-item:first-child {
    border-radius: 12px 12px 0 0 !important;
}

.list-group-item:last-child {
    border-radius: 0 0 12px 12px !important;
}

/* ── Footer ─────────────────────────────────────────── */
footer {
    background: #0d1f33 !important;
}

/* ── Alerts ─────────────────────────────────────────── */
.alert {
    border-radius: 10px !important;
    border: none;
    font-size: 0.9rem;
}

/* ── Section Titles ──────────────────