:root {
    /* Barvy školy ZŠ Pod Montací */
    --primary: #0066cc;        /* Modrá hlavní */
    --primary-dark: #004999;   /* Tmavší modrá */
    --primary-light: #e6f2ff;  /* Světle modrá */
    --secondary: #ff9800;      /* Oranžová akcent */
    --success: #4caf50;
    --danger: #f44336;
    --warning: #ff9800;
    --info: #2196f3;
    
    /* Neutrální barvy */
    --white: #ffffff;
    --gray-50: #fafafa;
    --gray-100: #f5f5f5;
    --gray-200: #eeeeee;
    --gray-300: #e0e0e0;
    --gray-400: #bdbdbd;
    --gray-500: #9e9e9e;
    --gray-600: #757575;
    --gray-700: #616161;
    --gray-800: #424242;
    --gray-900: #212121;
    
    /* Stíny */
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
    --shadow-xl: 0 20px 25px rgba(0,0,0,0.15);
    
    /* Rozměry */
    --border-radius: 12px;
    --border-radius-sm: 8px;
    --container-width: 1200px;
    --header-height: 70px;
}

* {
    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(--gray-800);
    background: var(--gray-50);
    min-height: 100vh;
}

/* ============================================
   CONTAINER
   ============================================ */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* ============================================
   HEADER
   ============================================ */
.main-header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: var(--white);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--header-height);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: var(--header-height);
    gap: 20px;
}

.header-logo {
    display: flex;
    align-items: center;
    gap: 15px;
}

.header-logo img {
    height: 50px;
    width: auto;
}

.main-header h1 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 15px;
    font-size: 0.95rem;
}

.user-info span {
    display: none;
}

/* ============================================
   NAVIGATION
   ============================================ */
.main-nav {
    background: var(--white);
    border-bottom: 1px solid var(--gray-200);
    box-shadow: var(--shadow-sm);
}

.nav-menu {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    padding: 10px 0;
}

.nav-menu li a {
    display: block;
    padding: 12px 20px;
    color: var(--gray-700);
    text-decoration: none;
    border-radius: var(--border-radius-sm);
    font-weight: 500;
    transition: all 0.2s;
    white-space: nowrap;
}

.nav-menu li a:hover {
    background: var(--primary-light);
    color: var(--primary);
}

.nav-menu li a.active {
    background: var(--primary);
    color: var(--white);
}

/* ============================================
   MAIN CONTENT
   ============================================ */
main.container {
    padding-top: 30px;
    padding-bottom: 30px;
    min-height: calc(100vh - var(--header-height) - 100px);
}

/* ============================================
   CARDS & TILES (DLAŽDICE)
   ============================================ */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.card {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s;
    border: 1px solid var(--gray-200);
}

.card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--gray-100);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--gray-800);
    margin: 0;
}

.card-body {
    color: var(--gray-700);
}

.card-footer {
    margin-top: 20px;
    padding-top: 15px;
    border-top: 1px solid var(--gray-100);
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.card-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: var(--border-radius-sm);
    margin-bottom: 15px;
}

/* Statistické karty */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow-md);
    border-left: 4px solid var(--primary);
    transition: all 0.3s;
}

.stat-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.stat-card .stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary);
    line-height: 1;
    margin-bottom: 8px;
}

.stat-card .stat-label {
    font-size: 0.95rem;
    color: var(--gray-600);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-card.success {
    border-left-color: var(--success);
}

.stat-card.success .stat-value {
    color: var(--success);
}

.stat-card.warning {
    border-left-color: var(--warning);
}

.stat-card.warning .stat-value {
    color: var(--warning);
}

.stat-card.danger {
    border-left-color: var(--danger);
}

.stat-card.danger .stat-value {
    color: var(--danger);
}

.stat-card.info {
    border-left-color: var(--info);
}

.stat-card.info .stat-value {
    color: var(--info);
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
    display: inline-block;
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 500;
    text-align: center;
    text-decoration: none;
    border: none;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
    line-height: 1.5;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--primary-dark);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--gray-200);
    color: var(--gray-800);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--gray-300);
}

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

.btn-success:hover:not(:disabled) {
    background: #388e3c;
}

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

.btn-danger:hover:not(:disabled) {
    background: #d32f2f;
}

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

.btn-warning:hover:not(:disabled) {
    background: #f57c00;
}

.btn-sm {
    padding: 8px 16px;
    font-size: 0.9rem;
}

.btn-lg {
    padding: 16px 32px;
    font-size: 1.1rem;
}

.btn-block {
    display: block;
    width: 100%;
}

.btn-group {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

/* ============================================
   FORMS
   ============================================ */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--gray-700);
}

.form-group label.required::after {
    content: ' *';
    color: var(--danger);
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group input[type="password"],
.form-group input[type="number"],
.form-group input[type="date"],
.form-group input[type="tel"],
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    font-size: 1rem;
    border: 2px solid var(--gray-300);
    border-radius: var(--border-radius-sm);
    transition: all 0.2s;
    font-family: inherit;
    background: var(--white);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-light);
}

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

.form-group select {
    cursor: pointer;
}

.form-group input[type="checkbox"],
.form-group input[type="radio"] {
    width: auto;
    margin-right: 8px;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.form-help {
    font-size: 0.875rem;
    color: var(--gray-600);
    margin-top: 4px;
}

.form-error {
    font-size: 0.875rem;
    color: var(--danger);
    margin-top: 4px;
}

/* ============================================
   TABLE
   ============================================ */
.table-container {
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    margin-top: 20px;
}

.table-wrapper {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
}

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

thead th {
    padding: 16px;
    text-align: left;
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 0.5px;
}

tbody tr {
    border-bottom: 1px solid var(--gray-200);
    transition: background 0.2s;
}

tbody tr:last-child {
    border-bottom: none;
}

tbody tr:hover {
    background: var(--gray-50);
}

tbody td {
    padding: 16px;
    color: var(--gray-700);
}

.table-actions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

/* ============================================
   ALERTS
   ============================================ */
.alert {
    padding: 16px 20px;
    border-radius: var(--border-radius-sm);
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 500;
    box-shadow: var(--shadow-sm);
}

.alert-success {
    background: #e8f5e9;
    color: #2e7d32;
    border-left: 4px solid var(--success);
}

.alert-error {
    background: #ffebee;
    color: #c62828;
    border-left: 4px solid var(--danger);
}

.alert-warning {
    background: #fff3e0;
    color: #e65100;
    border-left: 4px solid var(--warning);
}

.alert-info {
    background: #e3f2fd;
    color: #1565c0;
    border-left: 4px solid var(--info);
}

/* ============================================
   BADGES
   ============================================ */
.badge {
    display: inline-block;
    padding: 4px 12px;
    font-size: 0.85rem;
    font-weight: 600;
    border-radius: 20px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

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

.badge-success {
    background: #e8f5e9;
    color: var(--success);
}

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

.badge-warning {
    background: #fff3e0;
    color: var(--warning);
}

.badge-info {
    background: #e3f2fd;
    color: var(--info);
}

.badge-secondary {
    background: var(--gray-200);
    color: var(--gray-700);
}

/* ============================================
   FOOTER
   ============================================ */
.main-footer {
    background: var(--gray-800);
    color: var(--gray-300);
    padding: 30px 0;
    margin-top: 50px;
    text-align: center;
}

.main-footer p {
    margin: 0;
}

/* ============================================
   PAGE HEADER
   ============================================ */
.page-header {
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 3px solid var(--primary);
}

.page-header h1 {
    font-size: 2rem;
    color: var(--gray-800);
    margin-bottom: 8px;
}

.page-header p {
    color: var(--gray-600);
    font-size: 1.1rem;
}

.page-header-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

/* ============================================
   FILTERS
   ============================================ */
.filters {
    background: var(--white);
    padding: 20px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    margin-bottom: 20px;
}

.filters-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    align-items: end;
}

/* ============================================
   MODAL / DIALOG
   ============================================ */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
}

.modal {
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-xl);
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    padding: 24px;
    border-bottom: 1px solid var(--gray-200);
}

.modal-header h2 {
    margin: 0;
    font-size: 1.5rem;
    color: var(--gray-800);
}

.modal-body {
    padding: 24px;
}

.modal-footer {
    padding: 24px;
    border-top: 1px solid var(--gray-200);
    display: flex;
    gap: 10px;
    justify-content: flex-end;
}

/* ============================================
   LOADING
   ============================================ */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid var(--gray-300);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* ============================================
   EMPTY STATE
   ============================================ */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--gray-600);
}

.empty-state-icon {
    font-size: 4rem;
    margin-bottom: 20px;
}

.empty-state h3 {
    font-size: 1.5rem;
    color: var(--gray-700);
    margin-bottom: 10px;
}

.empty-state p {
    font-size: 1rem;
    margin-bottom: 20px;
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (min-width: 768px) {
    .user-info span {
        display: inline;
    }
    
    .main-header h1 {
        font-size: 1.75rem;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        flex-direction: column;
        gap: 5px;
    }
    
    .nav-menu li {
        width: 100%;
    }
    
    .nav-menu li a {
        width: 100%;
    }
    
    .cards-grid {
        grid-template-columns: 1fr;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .table-container {
        overflow-x: auto;
    }
    
    table {
        min-width: 600px;
    }
    
    .btn-group {
        flex-direction: column;
    }
    
    .btn-group .btn {
        width: 100%;
    }
    
    .page-header h1 {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .header-content {
        flex-direction: column;
        height: auto;
        padding: 15px 0;
    }
    
    .header-logo {
        flex-direction: column;
        text-align: center;
    }
    
    .main-header h1 {
        font-size: 1.25rem;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .page-header-actions {
        flex-direction: column;
        align-items: stretch;
    }
    
    .page-header-actions .btn {
        width: 100%;
    }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.text-muted {
    color: var(--gray-600);
}

.text-primary {
    color: var(--primary);
}

.text-success {
    color: var(--success);
}

.text-danger {
    color: var(--danger);
}

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.hidden {
    display: none;
}