:root {
    --primary: #1e40af;
    --primary-light: #3b82f6;
    --primary-dark: #1e3a8a;
    --accent: #0ea5e9;
    --bg: #f0f4f8;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --success: #10b981;
    --danger: #ef4444;
    --shadow: 0 4px 24px rgba(30, 64, 175, 0.08);
    --shadow-hover: 0 8px 32px rgba(30, 64, 175, 0.16);
    --radius: 16px;
    --radius-sm: 10px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

/* ── Header ─────────────────────────────── */

.header {
    background: var(--card-bg);
    color: var(--text);
    padding: 2rem 1rem 1.5rem;
    text-align: center;
    position: relative;
    border-bottom: 3px solid var(--primary);
    box-shadow: 0 2px 16px rgba(30, 64, 175, 0.06);
}

.header-logo {
    height: 56px;
    position: relative;
    z-index: 1;
    margin-bottom: 0.5rem;
}

.header p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
    font-weight: 500;
}

/* ── Container ──────────────────────────── */

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

/* ── Breadcrumb / Back Button ───────────── */

.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--primary);
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    padding: 0.6rem 1.2rem;
    border-radius: var(--radius-sm);
    border: none;
    background: var(--card-bg);
    box-shadow: var(--shadow);
    transition: var(--transition);
    margin-bottom: 1.5rem;
}

.back-btn:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-1px);
    box-shadow: var(--shadow-hover);
}

/* ── Section Title ──────────────────────── */

.section-title {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

.section-title i {
    color: var(--primary);
    font-size: 1.1rem;
}

/* ── Card Grid ──────────────────────────── */

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 1.25rem;
}

/* ── Category Card ──────────────────────── */

.category-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 2rem 1.5rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow);
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.category-card::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.category-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-light);
}

.category-card:hover::after {
    transform: scaleX(1);
}

.category-card .icon-wrap {
    width: 72px;
    height: 72px;
    border-radius: 50%;
    background: linear-gradient(135deg, rgba(30, 64, 175, 0.08), rgba(14, 165, 233, 0.08));
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.25rem;
    transition: var(--transition);
}

.category-card:hover .icon-wrap {
    background: linear-gradient(135deg, var(--primary), var(--accent));
}

.category-card .icon-wrap i {
    font-size: 1.75rem;
    color: var(--primary);
    transition: var(--transition);
}

.category-card:hover .icon-wrap i {
    color: white;
}

.category-card h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 0.35rem;
    color: var(--text);
}

.category-card .card-desc {
    font-size: 0.85rem;
    color: var(--text-muted);
    line-height: 1.4;
}

.category-card .badge {
    display: inline-block;
    margin-top: 0.75rem;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.badge-secure {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger);
}

/* ── Subcategory Card ───────────────────── */

.sub-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 1.5rem;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow);
    border: 2px solid transparent;
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.sub-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-light);
}

.sub-card .sub-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-sm);
    background: linear-gradient(135deg, rgba(30, 64, 175, 0.08), rgba(14, 165, 233, 0.08));
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: var(--transition);
}

.sub-card:hover .sub-icon {
    background: linear-gradient(135deg, var(--primary), var(--accent));
}

.sub-card .sub-icon i {
    font-size: 1.35rem;
    color: var(--primary);
    transition: var(--transition);
}

.sub-card:hover .sub-icon i {
    color: white;
}

.sub-card .sub-info h4 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 0.2rem;
}

.sub-card .sub-info p {
    font-size: 0.85rem;
    color: var(--text-muted);
    line-height: 1.4;
}

.sub-card .arrow {
    margin-left: auto;
    color: var(--text-muted);
    font-size: 1rem;
    transition: var(--transition);
}

.sub-card:hover .arrow {
    color: var(--primary);
    transform: translateX(4px);
}

/* ── Modal Overlay ──────────────────────── */

.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(6px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    padding: 1rem;
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 2rem;
    width: 100%;
    max-width: 420px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.2);
    transform: translateY(20px) scale(0.95);
    transition: var(--transition);
}

.modal-overlay.active .modal {
    transform: translateY(0) scale(1);
}

.modal h2 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 0.5rem;
    text-align: center;
}

.modal .modal-subtitle {
    font-size: 0.9rem;
    color: var(--text-muted);
    text-align: center;
    margin-bottom: 1.5rem;
}

.modal .step { display: none; }
.modal .step.active { display: block; }

/* ── Form Elements ──────────────────────── */

.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 0.4rem;
}

.form-group input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-family: inherit;
    color: var(--text);
    transition: var(--transition);
    outline: none;
}

.form-group input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(30, 64, 175, 0.12);
}

.form-group input::placeholder {
    color: var(--text-muted);
}

.code-inputs {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    margin: 1.5rem 0;
}

.code-inputs input {
    width: 48px;
    height: 56px;
    text-align: center;
    font-size: 1.5rem;
    font-weight: 700;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    outline: none;
    transition: var(--transition);
}

.code-inputs input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(30, 64, 175, 0.12);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.85rem 1.5rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(30, 64, 175, 0.3);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-secondary {
    background: transparent;
    color: var(--text-muted);
    margin-top: 0.75rem;
}

.btn-secondary:hover {
    color: var(--primary);
}

/* ── Alert ──────────────────────────────── */

.alert {
    padding: 0.75rem 1rem;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    font-weight: 500;
    margin-bottom: 1rem;
    display: none;
}

.alert.show { display: block; }

.alert-error {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger);
    border: 1px solid rgba(239, 68, 68, 0.2);
}

.alert-success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success);
    border: 1px solid rgba(16, 185, 129, 0.2);
}

.alert-info {
    background: rgba(14, 165, 233, 0.1);
    color: var(--accent);
    border: 1px solid rgba(14, 165, 233, 0.2);
}

/* ── Loading ────────────────────────────── */

.loading {
    text-align: center;
    padding: 3rem;
    color: var(--text-muted);
}

.spinner {
    display: inline-block;
    width: 36px;
    height: 36px;
    border: 3px solid var(--border);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ── Animations ─────────────────────────── */

.fade-in {
    animation: fadeIn 0.4s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

.slide-in {
    animation: slideIn 0.4s ease;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateX(-16px); }
    to { opacity: 1; transform: translateX(0); }
}

/* ── Footer ─────────────────────────────── */

.footer {
    text-align: center;
    padding: 2rem 1rem;
    color: var(--text-muted);
    font-size: 0.8rem;
    border-top: 1px solid var(--border);
    margin-top: 3rem;
}

/* ── Responsive ─────────────────────────── */

@media (max-width: 640px) {
    .header { padding: 1.5rem 1rem 1.25rem; }
    .header-logo { height: 44px; }
    .container { padding: 1.25rem 0.75rem; }
    .card-grid { grid-template-columns: 1fr; gap: 1rem; }
    .category-card { padding: 1.5rem 1rem; }
    .category-card .icon-wrap { width: 60px; height: 60px; }
    .category-card .icon-wrap i { font-size: 1.5rem; }
    .sub-card { padding: 1.25rem; }
    .modal { padding: 1.5rem; }
    .code-inputs input { width: 42px; height: 48px; font-size: 1.25rem; }
}