/* Modern CSS Framework for Test System - 2025 */

:root {
    --primary-color: #2563eb;
    --secondary-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --success-color: #22c55e;
    --dark-color: #1f2937;
    --light-color: #f3f4f6;
    --border-color: #d1d5db;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: #ffffff;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.container-fluid {
    width: 100%;
    padding: 0 1rem;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-bottom: 1rem;
    font-weight: 600;
    line-height: 1.2;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.5rem 1rem;
    font-size: 1rem;
    font-weight: 500;
    text-align: center;
    text-decoration: none;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.3s ease;
    line-height: 1.5;
}

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

.btn-primary:hover {
    background-color: #1d4ed8;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

.btn-success:hover {
    background-color: #16a34a;
}

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

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

.btn-secondary {
    background-color: var(--light-color);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: #e5e7eb;
}

.btn-sm {
    padding: 0.25rem 0.75rem;
    font-size: 0.875rem;
}

.btn-lg {
    padding: 0.75rem 1.5rem;
    font-size: 1.125rem;
}

/* Forms */
.form-group {
    margin-bottom: 1rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-control {
    display: block;
    width: 100%;
    padding: 0.5rem 0.75rem;
    font-size: 1rem;
    line-height: 1.5;
    color: var(--text-primary);
    background-color: white;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-control::placeholder {
    color: var(--text-secondary);
}

input[type="checkbox"],
input[type="radio"] {
    width: auto;
    margin-right: 0.5rem;
    cursor: pointer;
}

/* Tables */
.table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1rem;
    background-color: white;
}

.table th,
.table td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.table thead th {
    background-color: var(--dark-color);
    color: white;
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.875rem;
    letter-spacing: 0.05em;
}

.table tbody tr:hover {
    background-color: var(--light-color);
}

.table-striped tbody tr:nth-child(odd) {
    background-color: #f9fafb;
}

.table-bordered {
    border: 1px solid var(--border-color);
}

.table-bordered th,
.table-bordered td {
    border: 1px solid var(--border-color);
}

/* Cards */
.card {
    background-color: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    margin-bottom: 1.5rem;
}

.card-header {
    padding: 1rem 1.5rem;
    background-color: var(--light-color);
    border-bottom: 1px solid var(--border-color);
    font-weight: 600;
}

.card-body {
    padding: 1.5rem;
}

.card-footer {
    padding: 1rem 1.5rem;
    background-color: var(--light-color);
    border-top: 1px solid var(--border-color);
}

/* Alerts */
.alert {
    padding: 1rem 1.5rem;
    margin-bottom: 1rem;
    border-radius: var(--radius-md);
    border-left: 4px solid;
}

.alert-success {
    background-color: #d1fae5;
    border-color: var(--success-color);
    color: #065f46;
}

.alert-danger {
    background-color: #fee2e2;
    border-color: var(--danger-color);
    color: #991b1b;
}

.alert-warning {
    background-color: #fef3c7;
    border-color: var(--warning-color);
    color: #92400e;
}

.alert-info {
    background-color: #dbeafe;
    border-color: var(--primary-color);
    color: #1e40af;
}

/* Navigation */
.navbar {
    background-color: var(--dark-color);
    padding: 1rem 0;
    box-shadow: var(--shadow-md);
}

.navbar-nav {
    display: flex;
    list-style: none;
    gap: 1rem;
}

.nav-link {
    color: white;
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    transition: background-color 0.3s ease;
}

.nav-link:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

.nav-link.active {
    background-color: var(--primary-color);
}

/* Badges */
.badge {
    display: inline-block;
    padding: 0.25rem 0.5rem;
    font-size: 0.75rem;
    font-weight: 600;
    line-height: 1;
    text-align: center;
    white-space: nowrap;
    border-radius: var(--radius-sm);
}

.badge-primary {
    background-color: var(--primary-color);
    color: white;
}

.badge-success {
    background-color: var(--success-color);
    color: white;
}

.badge-danger {
    background-color: var(--danger-color);
    color: white;
}

.badge-warning {
    background-color: var(--warning-color);
    color: white;
}

/* Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.p-1 { padding: 0.5rem; }
.p-2 { padding: 1rem; }
.p-3 { padding: 1.5rem; }
.p-4 { padding: 2rem; }

.d-none { display: none; }
.d-block { display: block; }
.d-inline { display: inline; }
.d-inline-block { display: inline-block; }
.d-flex { display: flex; }

.flex-row { flex-direction: row; }
.flex-column { flex-direction: column; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.align-center { align-items: center; }

.w-100 { width: 100%; }
.h-100 { height: 100%; }

/* Responsive Grid */
.row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -0.5rem;
}

.col {
    flex: 1;
    padding: 0 0.5rem;
}

.col-1 { flex: 0 0 8.333333%; max-width: 8.333333%; }
.col-2 { flex: 0 0 16.666667%; max-width: 16.666667%; }
.col-3 { flex: 0 0 25%; max-width: 25%; }
.col-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
.col-6 { flex: 0 0 50%; max-width: 50%; }
.col-8 { flex: 0 0 66.666667%; max-width: 66.666667%; }
.col-12 { flex: 0 0 100%; max-width: 100%; }

/* Loading Spinner */
.spinner {
    border: 4px solid var(--light-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    max-width: 500px;
    width: 90%;
    box-shadow: var(--shadow-lg);
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 0.5rem;
    }
    
    .navbar-nav {
        flex-direction: column;
    }
    
    .table {
        font-size: 0.875rem;
    }
    
    .table th,
    .table td {
        padding: 0.5rem;
    }
    
    [class*="col-"] {
        flex: 0 0 100%;
        max-width: 100%;
    }
}

/* Print Styles */
@media print {
    .btn,
    .navbar,
    .no-print {
        display: none;
    }
    
    body {
        color: black;
        background: white;
    }
}