/* ==============================================================
   OMR EXAM SCANNER — DESIGN SYSTEM (CLEAN WHITE MINIMALIST)
   ============================================================== */

:root {
    --bg-main: #f8fafc;
    --bg-surface: #ffffff;
    --bg-subtle: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border-color: #e2e8f0;
    --border-subtle: #f1f5f9;
    
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-light: #eff6ff;
    
    --success: #10b981;
    --success-light: #ecfdf5;
    --success-border: #a7f3d0;
    
    --danger: #ef4444;
    --danger-light: #fef2f2;
    --danger-border: #fecaca;
    
    --warning: #f59e0b;
    --warning-light: #fffbeb;
    --warning-border: #fde68a;
    
    --info: #0284c7;
    --info-light: #f0f9ff;
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-full: 9999px;
    
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

body {
    background-color: var(--bg-main);
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: 14px;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 16px;
}

/* Navbar */
.navbar {
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 40;
    height: 64px;
    display: flex;
    align-items: center;
}

.navbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
}

.brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 17px;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
}

.brand-icon {
    width: 34px;
    height: 34px;
    background: var(--primary);
    color: #fff;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 16px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 8px;
    list-style: none;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    font-weight: 500;
    font-size: 13.5px;
    transition: all 0.15s ease;
}

.nav-link:hover, .nav-link.active {
    background: var(--bg-subtle);
    color: var(--primary);
}

.user-badge {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 6px 12px;
    background: var(--bg-subtle);
    border-radius: var(--radius-full);
    font-size: 13px;
    font-weight: 500;
}

/* Typography & Headings */
h1, h2, h3, h4, h5 {
    color: var(--text-primary);
    font-weight: 700;
    line-height: 1.25;
}

.page-header {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin: 24px 0 20px 0;
}

.page-title {
    font-size: 22px;
    font-weight: 700;
}

.page-subtitle {
    font-size: 13.5px;
    color: var(--text-secondary);
    margin-top: 4px;
}

/* Card */
.card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: 20px;
    margin-bottom: 20px;
}

.card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-bottom: 14px;
    margin-bottom: 16px;
    border-bottom: 1px solid var(--border-color);
}

.card-title {
    font-size: 16px;
    font-weight: 600;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 9px 16px;
    border-radius: var(--radius-sm);
    font-size: 13.5px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    border: 1px solid transparent;
    transition: all 0.15s ease;
    min-height: 38px;
    white-space: nowrap;
}

.btn-sm {
    padding: 6px 12px;
    font-size: 12.5px;
    min-height: 32px;
}

.btn-lg {
    padding: 12px 24px;
    font-size: 15px;
    min-height: 46px;
}

.btn-primary {
    background: var(--primary);
    color: #ffffff;
}

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

.btn-secondary {
    background: var(--bg-subtle);
    color: var(--text-primary);
    border-color: var(--border-color);
}

.btn-secondary:hover {
    background: #e2e8f0;
}

.btn-outline {
    background: transparent;
    color: var(--primary);
    border-color: var(--primary);
}

.btn-outline:hover {
    background: var(--primary-light);
}

.btn-danger {
    background: var(--danger);
    color: #ffffff;
}

.btn-danger:hover {
    background: #dc2626;
}

.btn-success {
    background: var(--success);
    color: #ffffff;
}

.btn-success:hover {
    background: #059669;
}

.btn-block {
    width: 100%;
}

/* Forms */
.form-group {
    margin-bottom: 16px;
}

.form-label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.form-control {
    width: 100%;
    padding: 9px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--bg-surface);
    color: var(--text-primary);
    font-size: 14px;
    font-family: inherit;
    transition: border-color 0.15s ease;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
}

/* Grid & Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.stat-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px 20px;
    box-shadow: var(--shadow-sm);
}

.stat-label {
    font-size: 12.5px;
    color: var(--text-secondary);
    font-weight: 500;
}

.stat-value {
    font-size: 26px;
    font-weight: 700;
    color: var(--text-primary);
    margin-top: 4px;
}

.stat-sub {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 2px;
}

/* Tables */
.table-responsive {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    width: 100%;
}

.table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
    font-size: 13.5px;
}

.table th {
    background: var(--bg-subtle);
    color: var(--text-secondary);
    font-weight: 600;
    padding: 11px 14px;
    border-bottom: 1px solid var(--border-color);
    white-space: nowrap;
}

.table td {
    padding: 12px 14px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
}

.table tr:hover td {
    background: #f8fafc;
}

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 3px 8px;
    border-radius: var(--radius-full);
    font-size: 11.5px;
    font-weight: 600;
}

.badge-draft { background: #e2e8f0; color: #475569; }
.badge-active { background: var(--success-light); color: var(--success); border: 1px solid var(--success-border); }
.badge-closed { background: #fee2e2; color: #b91c1c; }
.badge-review { background: var(--warning-light); color: #b45309; border: 1px solid var(--warning-border); }

/* Alerts */
.alert {
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    margin-bottom: 16px;
    font-size: 13.5px;
}

.alert-success { background: var(--success-light); border: 1px solid var(--success-border); color: #065f46; }
.alert-error { background: var(--danger-light); border: 1px solid var(--danger-border); color: #991b1b; }
.alert-warning { background: var(--warning-light); border: 1px solid var(--warning-border); color: #92400e; }
.alert-info { background: var(--info-light); border: 1px solid #bae6fd; color: #0369a1; }

/* Interactive Key Matrix for Answer Keys */
.key-matrix-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 12px;
}

.key-item-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 8px 12px;
}

.key-item-num {
    font-weight: 700;
    font-size: 13.5px;
    width: 36px;
    color: var(--text-secondary);
}

.key-options-group {
    display: flex;
    gap: 6px;
}

.key-bubble-btn {
    width: 34px;
    height: 34px;
    border-radius: 50%;
    border: 1.5px solid #cbd5e1;
    background: #ffffff;
    font-size: 13px;
    font-weight: 700;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.12s ease;
}

.key-bubble-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.key-bubble-btn.selected {
    background: var(--primary);
    border-color: var(--primary);
    color: #ffffff;
}

.weight-input {
    width: 55px;
    padding: 4px 6px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 12px;
    text-align: center;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .navbar {
        height: auto;
        padding: 10px 0;
    }
    .navbar-inner {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }
    .nav-links {
        flex-wrap: wrap;
        width: 100%;
    }
    .page-header {
        flex-direction: column;
        align-items: flex-start;
    }
}