/* College Management System - Modern CSS Styles */

/* CSS Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    margin-bottom: 1rem;
    color: #2c3e50;
}

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; }

p {
    margin-bottom: 1rem;
    color: #555;
}

a {
    color: #007bff;
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #0056b3;
    text-decoration: underline;
}

/* Layout Components */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    width: 100%;
}

.container-fluid {
    width: 100%;
    padding: 0 20px;
}

.row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -15px;
}

.col {
    flex: 1;
    padding: 0 15px;
}

.col-1 { flex: 0 0 8.333333%; }
.col-2 { flex: 0 0 16.666667%; }
.col-3 { flex: 0 0 25%; }
.col-4 { flex: 0 0 33.333333%; }
.col-6 { flex: 0 0 50%; }
.col-8 { flex: 0 0 66.666667%; }
.col-9 { flex: 0 0 75%; }
.col-12 { flex: 0 0 100%; }

/* Header Styles */
header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1rem 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-menu a {
    color: white;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}

.nav-menu a:hover {
    background-color: rgba(255,255,255,0.2);
    text-decoration: none;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: rgba(255,255,255,0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
}

/* Main Content */
main {
    flex: 1;
    padding: 2rem 0;
}

.page-header {
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #e9ecef;
}

.page-title {
    color: #2c3e50;
    margin-bottom: 0.5rem;
}

.page-subtitle {
    color: #6c757d;
    font-size: 1.1rem;
    margin: 0;
}

/* Cards */
.card {
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 15px rgba(0,0,0,0.08);
    margin-bottom: 2rem;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 25px rgba(0,0,0,0.12);
}

.card-header {
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    padding: 1.5rem;
    border-bottom: 1px solid #dee2e6;
}

.card-title {
    margin: 0;
    color: #495057;
    font-size: 1.25rem;
}

.card-body {
    padding: 1.5rem;
}

.card-footer {
    background-color: #f8f9fa;
    padding: 1rem 1.5rem;
    border-top: 1px solid #dee2e6;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #495057;
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
    background-color: white;
}

.form-control:focus {
    outline: none;
    border-color: #007bff;
    box-shadow: 0 0 0 3px rgba(0,123,255,0.1);
}

.form-control.is-invalid {
    border-color: #dc3545;
}

.form-control.is-valid {
    border-color: #28a745;
}

.invalid-feedback {
    display: block;
    color: #dc3545;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.valid-feedback {
    display: block;
    color: #28a745;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

select.form-control {
    cursor: pointer;
}

textarea.form-control {
    resize: vertical;
    min-height: 100px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    line-height: 1.5;
}

.btn:hover {
    text-decoration: none;
    transform: translateY(-1px);
}

.btn-primary {
    background: linear-gradient(135deg, #007bff 0%, #0056b3 100%);
    color: white;
}

.btn-primary:hover {
    background: linear-gradient(135deg, #0056b3 0%, #004085 100%);
    color: white;
}

.btn-secondary {
    background: linear-gradient(135deg, #6c757d 0%, #545b62 100%);
    color: white;
}

.btn-success {
    background: linear-gradient(135deg, #28a745 0%, #1e7e34 100%);
    color: white;
}

.btn-danger {
    background: linear-gradient(135deg, #dc3545 0%, #c82333 100%);
    color: white;
}

.btn-warning {
    background: linear-gradient(135deg, #ffc107 0%, #e0a800 100%);
    color: #212529;
}

.btn-info {
    background: linear-gradient(135deg, #17a2b8 0%, #138496 100%);
    color: white;
}

.btn-light {
    background-color: #f8f9fa;
    color: #495057;
    border: 1px solid #dee2e6;
}

.btn-outline-primary {
    background: transparent;
    color: #007bff;
    border: 2px solid #007bff;
}

.btn-outline-primary:hover {
    background: #007bff;
    color: white;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.btn-block {
    width: 100%;
}

/* Tables */
.table-responsive {
    overflow-x: auto;
    margin-bottom: 1rem;
}

.table {
    width: 100%;
    border-collapse: collapse;
    background-color: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.table th,
.table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid #dee2e6;
}

.table th {
    background-color: #f8f9fa;
    font-weight: 600;
    color: #495057;
    text-transform: uppercase;
    font-size: 0.875rem;
    letter-spacing: 0.5px;
}

.table tbody tr:hover {
    background-color: #f8f9fa;
}

.table-striped tbody tr:nth-child(odd) {
    background-color: #f8f9fa;
}

/* Alerts */
.alert {
    padding: 1rem 1.5rem;
    border-radius: 8px;
    margin-bottom: 1rem;
    border-left: 4px solid;
}

.alert-success {
    background-color: #d4edda;
    border-color: #28a745;
    color: #155724;
}

.alert-danger {
    background-color: #f8d7da;
    border-color: #dc3545;
    color: #721c24;
}

.alert-warning {
    background-color: #fff3cd;
    border-color: #ffc107;
    color: #856404;
}

.alert-info {
    background-color: #d1ecf1;
    border-color: #17a2b8;
    color: #0c5460;
}

/* Badges */
.badge {
    display: inline-block;
    padding: 0.375rem 0.75rem;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 50px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge-primary { background-color: #007bff; color: white; }
.badge-secondary { background-color: #6c757d; color: white; }
.badge-success { background-color: #28a745; color: white; }
.badge-danger { background-color: #dc3545; color: white; }
.badge-warning { background-color: #ffc107; color: #212529; }
.badge-info { background-color: #17a2b8; color: white; }

/* Progress Bars */
.progress {
    height: 1rem;
    background-color: #e9ecef;
    border-radius: 0.5rem;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #007bff, #0056b3);
    transition: width 0.6s ease;
}

/* Pagination */
.pagination {
    display: flex;
    justify-content: center;
    list-style: none;
    gap: 0.5rem;
    margin: 2rem 0;
}

.pagination a {
    padding: 0.75rem 1rem;
    border: 1px solid #dee2e6;
    border-radius: 5px;
    color: #007bff;
    transition: all 0.3s ease;
}

.pagination a:hover {
    background-color: #e9ecef;
    text-decoration: none;
}

.pagination .active a {
    background-color: #007bff;
    color: white;
    border-color: #007bff;
}

/* Dashboard Widgets */
.dashboard-widget {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 2px 15px rgba(0,0,0,0.08);
    text-align: center;
    transition: transform 0.3s ease;
}

.dashboard-widget:hover {
    transform: translateY(-3px);
}

.widget-icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    margin: 0 auto 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 600;
    color: white;
}

.widget-icon.primary { background: linear-gradient(135deg, #007bff, #0056b3); }
.widget-icon.success { background: linear-gradient(135deg, #28a745, #1e7e34); }
.widget-icon.warning { background: linear-gradient(135deg, #ffc107, #e0a800); }
.widget-icon.danger { background: linear-gradient(135deg, #dc3545, #c82333); }

.widget-title {
    font-size: 2rem;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 0.5rem;
}

.widget-subtitle {
    color: #6c757d;
    font-size: 1rem;
}

/* Footer */
footer {
    background-color: #2c3e50;
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: auto;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.footer-links a {
    color: #bdc3c7;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: white;
    text-decoration: none;
}

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

.text-primary { color: #007bff; }
.text-secondary { color: #6c757d; }
.text-success { color: #28a745; }
.text-danger { color: #dc3545; }
.text-warning { color: #ffc107; }
.text-info { color: #17a2b8; }
.text-muted { color: #6c757d; }

.bg-primary { background-color: #007bff; }
.bg-secondary { background-color: #6c757d; }
.bg-success { background-color: #28a745; }
.bg-danger { background-color: #dc3545; }
.bg-warning { background-color: #ffc107; }
.bg-info { background-color: #17a2b8; }
.bg-light { background-color: #f8f9fa; }
.bg-dark { background-color: #343a40; }

.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }
.mt-5 { margin-top: 3rem; }

.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mb-5 { margin-bottom: 3rem; }

.p-1 { padding: 0.25rem; }
.p-2 { padding: 0.5rem; }
.p-3 { padding: 1rem; }
.p-4 { padding: 1.5rem; }
.p-5 { padding: 3rem; }

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

.justify-content-center { justify-content: center; }
.justify-content-between { justify-content: space-between; }
.align-items-center { align-items: center; }

.rounded { border-radius: 0.375rem; }
.rounded-circle { border-radius: 50%; }

.shadow { box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
.shadow-lg { box-shadow: 0 4px 25px rgba(0,0,0,0.15); }

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }
    
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-menu {
        flex-direction: column;
        gap: 0.5rem;
        width: 100%;
    }
    
    .row {
        margin: 0;
    }
    
    .col,
    .col-1, .col-2, .col-3, .col-4, .col-6, .col-8, .col-9, .col-12 {
        flex: 0 0 100%;
        padding: 0;
        margin-bottom: 1rem;
    }
    
    .table-responsive {
        font-size: 0.875rem;
    }
    
    .btn {
        width: 100%;
        margin-bottom: 0.5rem;
    }
    
    .dashboard-widget {
        margin-bottom: 1rem;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    html {
        font-size: 14px;
    }
    
    .card-body {
        padding: 1rem;
    }
    
    .table th,
    .table td {
        padding: 0.5rem;
    }
    
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.5rem; }
}

/* Print Styles */
@media print {
    header,
    footer,
    .btn,
    .nav-menu {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .card {
        box-shadow: none;
        border: 1px solid #ccc;
    }
    
    .page-break {
        page-break-before: always;
    }
}

/* Loading Spinner */
.spinner {
    border: 4px solid #f3f3f3;
    border-top: 4px solid #007bff;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 20px auto;
}

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

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: #c1c1c1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #a8a8a8;
}