/**
 * Aktivitäts-Tracker - Hauptstylesheet
 * Responsive Design mit Fokus auf Smartphone-Nutzung
 */

/* ===================================
   CSS VARIABLEN / THEME
   =================================== */
:root {
    /* Farben */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-secondary: #64748b;
    --color-success: #10b981;
    --color-success-light: #d1fae5;
    --color-danger: #ef4444;
    --color-danger-light: #fee2e2;
    --color-warning: #f59e0b;
    --color-warning-light: #fef3c7;
    --color-info: #06b6d4;
    
    /* Grautöne */
    --color-white: #ffffff;
    --color-gray-50: #f8fafc;
    --color-gray-100: #f1f5f9;
    --color-gray-200: #e2e8f0;
    --color-gray-300: #cbd5e1;
    --color-gray-400: #94a3b8;
    --color-gray-500: #64748b;
    --color-gray-600: #475569;
    --color-gray-700: #334155;
    --color-gray-800: #1e293b;
    --color-gray-900: #0f172a;
    
    /* Wochenend-Farben */
    --color-weekend: #fef2f2;
    --color-weekend-border: #fecaca;
    --color-saturday: #fbbf24;
    --color-sunday: #f87171;
    
    /* Schriften */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    
    /* Abstände */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Schatten */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    /* Übergänge */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;
}

/* ===================================
   RESET & BASIS
   =================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-gray-800);
    background: linear-gradient(135deg, var(--color-gray-50) 0%, var(--color-gray-100) 100%);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===================================
   TYPOGRAFIE
   =================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-gray-900);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: clamp(1.75rem, 5vw, 2.5rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.5rem); }
h4 { font-size: 1.125rem; }

p { margin-bottom: var(--spacing-md); }

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-dark);
}

/* ===================================
   LAYOUT
   =================================== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.container-fluid {
    width: 100%;
    padding: 0 var(--spacing-md);
}

.page-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.main-content {
    flex: 1;
    padding: var(--spacing-lg) 0;
}

/* ===================================
   HEADER / NAVIGATION
   =================================== */
.header {
    background: var(--color-white);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md);
    gap: var(--spacing-md);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-gray-900);
}

.logo-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    font-size: 1.25rem;
}

.nav {
    display: flex;
    gap: var(--spacing-sm);
}

.nav-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    color: var(--color-gray-600);
    font-weight: 500;
    transition: all var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
    background: var(--color-gray-100);
    color: var(--color-primary);
}

.nav-mobile-toggle {
    display: none;
    padding: var(--spacing-sm);
    background: transparent;
    border: none;
    cursor: pointer;
    color: var(--color-gray-700);
}

/* ===================================
   KARTEN / CARDS
   =================================== */
.card {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.card-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--color-gray-200);
    background: var(--color-gray-50);
}

.card-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin: 0;
}

.card-body {
    padding: var(--spacing-lg);
}

.card-footer {
    padding: var(--spacing-lg);
    border-top: 1px solid var(--color-gray-200);
    background: var(--color-gray-50);
}

/* ===================================
   BUTTONS
   =================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 0.9375rem;
    font-weight: 500;
    line-height: 1.5;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    white-space: nowrap;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: var(--color-white);
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

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

.btn-success {
    background: linear-gradient(135deg, var(--color-success) 0%, #059669 100%);
    color: var(--color-white);
}

.btn-danger {
    background: linear-gradient(135deg, var(--color-danger) 0%, #dc2626 100%);
    color: var(--color-white);
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--color-primary);
    color: var(--color-primary);
}

.btn-outline:hover:not(:disabled) {
    background: var(--color-primary);
    color: var(--color-white);
}

.btn-sm {
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.8125rem;
}

.btn-lg {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1.0625rem;
}

.btn-block {
    width: 100%;
}

.btn-icon {
    width: 40px;
    height: 40px;
    padding: 0;
    border-radius: var(--radius-full);
}

/* ===================================
   FORMULARE
   =================================== */
.form-group {
    margin-bottom: var(--spacing-lg);
}

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

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 1rem;
    line-height: 1.5;
    color: var(--color-gray-800);
    background: var(--color-white);
    border: 2px solid var(--color-gray-300);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    -webkit-appearance: none;
}

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

.form-input.error,
.form-select.error,
.form-textarea.error {
    border-color: var(--color-danger);
}

.form-textarea {
    min-height: 120px;
    resize: vertical;
}

.form-hint {
    margin-top: var(--spacing-xs);
    font-size: 0.875rem;
    color: var(--color-gray-500);
}

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

.form-check {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
}

.form-check-input {
    width: 20px;
    height: 20px;
    accent-color: var(--color-primary);
    cursor: pointer;
}

/* ===================================
   ALERTS / NACHRICHTEN
   =================================== */
.alert {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
}

.alert-success {
    background: var(--color-success-light);
    color: #065f46;
    border-left: 4px solid var(--color-success);
}

.alert-danger, .alert-error {
    background: var(--color-danger-light);
    color: #991b1b;
    border-left: 4px solid var(--color-danger);
}

.alert-warning {
    background: var(--color-warning-light);
    color: #92400e;
    border-left: 4px solid var(--color-warning);
}

.alert-info {
    background: #e0f2fe;
    color: #075985;
    border-left: 4px solid var(--color-info);
}

/* Welcome Message (ohne Hintergrund) */
.welcome-message {
    color: var(--color-success);
    font-size: 0.9375rem;
    margin: 0;
    padding: var(--spacing-sm) 0;
}

/* ===================================
   TABELLEN
   =================================== */
.table-responsive {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9375rem;
}

.table th,
.table td {
    padding: var(--spacing-sm) var(--spacing-md);
    text-align: left;
    border-bottom: 1px solid var(--color-gray-200);
}

.table th {
    background: var(--color-gray-50);
    font-weight: 600;
    color: var(--color-gray-700);
    white-space: nowrap;
}

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

.table-striped tbody tr:nth-child(even) {
    background: var(--color-gray-50);
}

/* ===================================
   KALENDER - MONATSANSICHT
   =================================== */
.calendar-container {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.calendar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    color: var(--color-white);
}

.calendar-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0;
}

.calendar-nav {
    display: flex;
    gap: var(--spacing-sm);
}

.calendar-nav-btn {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: var(--radius-full);
    color: var(--color-white);
    cursor: pointer;
    transition: background var(--transition-fast);
    font-size: 1.25rem;
}

.calendar-nav-btn:hover {
    background: rgba(255, 255, 255, 0.3);
}

.calendar-weekdays {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    background: var(--color-gray-100);
    border-bottom: 1px solid var(--color-gray-200);
}

.calendar-weekday {
    padding: var(--spacing-sm);
    text-align: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-gray-600);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.calendar-weekday.weekend {
    color: var(--color-danger);
    background: var(--color-weekend);
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 1px;
    background: var(--color-gray-200);
}

.calendar-day {
    aspect-ratio: 1;
    min-height: 50px;
    background: var(--color-white);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    padding: var(--spacing-xs);
}

.calendar-day:hover:not(.disabled):not(.other-month) {
    background: var(--color-gray-100);
}

.calendar-day.weekend {
    background: var(--color-weekend);
}

.calendar-day.today {
    background: var(--color-primary-light);
    color: var(--color-white);
}

.calendar-day.today .day-number {
    color: var(--color-white);
}

.calendar-day.other-month {
    opacity: 0.3;
    cursor: default;
}

.calendar-day.disabled {
    opacity: 0.5;
    cursor: not-allowed;
    background: var(--color-gray-100);
}

.calendar-day.checked {
    background: var(--color-success);
    color: var(--color-white);
}

.calendar-day.checked .day-number {
    color: var(--color-white);
}

.calendar-day.checked::after {
    content: '✓';
    position: absolute;
    bottom: 4px;
    right: 4px;
    font-size: 0.75rem;
    font-weight: 700;
}

.day-number {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-gray-800);
}

/* ===================================
   KALENDER - JAHRESANSICHT
   =================================== */
.year-calendar {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.year-calendar-table {
    width: 100%;
    min-width: 800px;
    border-collapse: collapse;
    font-size: 0.75rem;
}

.year-calendar-table th,
.year-calendar-table td {
    border: 1px solid var(--color-gray-200);
    text-align: center;
    padding: 2px;
}

.year-calendar-table th {
    background: var(--color-gray-100);
    font-weight: 600;
    position: sticky;
    top: 0;
    z-index: 10;
}

.year-calendar-table th.weekend {
    background: var(--color-weekend);
    color: var(--color-danger);
}

.year-calendar-table .month-label {
    position: sticky;
    left: 0;
    background: var(--color-gray-100);
    font-weight: 600;
    text-align: left;
    padding-left: var(--spacing-sm);
    min-width: 100px;
    z-index: 5;
}

.year-calendar-table td.day-cell {
    min-width: 28px;
    height: 28px;
    cursor: pointer;
    transition: background var(--transition-fast);
}

.year-calendar-table td.day-cell:hover:not(.disabled):not(.empty) {
    background: var(--color-gray-200);
}

.year-calendar-table td.day-cell.weekend {
    background: var(--color-weekend);
}

.year-calendar-table td.day-cell.checked {
    background: var(--color-success);
    color: var(--color-white);
}

.year-calendar-table td.day-cell.today {
    outline: 2px solid var(--color-primary);
    outline-offset: -2px;
}

.year-calendar-table td.day-cell.disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.year-calendar-table td.day-cell.empty {
    background: var(--color-gray-50);
    cursor: default;
}

/* ===================================
   ANSICHT-UMSCHALTER
   =================================== */
.view-switcher {
    display: flex;
    background: var(--color-gray-200);
    border-radius: var(--radius-md);
    padding: 3px;
    gap: 3px;
}

.view-switcher-btn {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-gray-600);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.view-switcher-btn.active {
    background: var(--color-white);
    color: var(--color-primary);
    box-shadow: var(--shadow-sm);
}

/* ===================================
   STATISTIK-KARTEN
   =================================== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-md);
}

.stat-card {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1.2;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--color-gray-500);
    margin-top: var(--spacing-xs);
}

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

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

/* ===================================
   GRUPPENANSICHT
   =================================== */
.group-overview {
    overflow-x: auto;
}

.group-calendar-table {
    width: 100%;
    min-width: 600px;
    border-collapse: collapse;
}

.group-calendar-table th,
.group-calendar-table td {
    border: 1px solid var(--color-gray-200);
    padding: var(--spacing-sm);
    text-align: center;
}

.group-calendar-table th {
    background: var(--color-gray-100);
    font-weight: 600;
    position: sticky;
    top: 0;
}

.group-calendar-table .user-name {
    text-align: left;
    position: sticky;
    left: 0;
    background: var(--color-white);
    font-weight: 500;
    min-width: 120px;
}

.group-calendar-table td.checked {
    background: var(--color-success);
}

.group-calendar-table td.checked::after {
    content: '✓';
    color: var(--color-white);
    font-weight: 700;
}

/* ===================================
   TABS
   =================================== */
.tabs {
    display: flex;
    border-bottom: 2px solid var(--color-gray-200);
    gap: var(--spacing-xs);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.tab {
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    background: transparent;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-gray-500);
    cursor: pointer;
    white-space: nowrap;
    transition: all var(--transition-fast);
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
}

.tab:hover {
    color: var(--color-gray-700);
}

.tab.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.tab-content {
    display: none;
    padding: var(--spacing-lg) 0;
}

.tab-content.active {
    display: block;
}

/* ===================================
   MODAL / DIALOG
   =================================== */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

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

.modal {
    background: var(--color-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    transform: scale(0.95);
    transition: transform var(--transition-normal);
}

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

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--color-gray-200);
}

.modal-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin: 0;
}

.modal-close {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    border-radius: var(--radius-full);
    cursor: pointer;
    color: var(--color-gray-500);
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--color-gray-100);
    color: var(--color-gray-700);
}

.modal-body {
    padding: var(--spacing-lg);
}

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

/* ===================================
   BADGE / TAGS
   =================================== */
.badge {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    text-transform: uppercase;
    letter-spacing: 0.025em;
}

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

.badge-success {
    background: var(--color-success-light);
    color: #065f46;
}

.badge-danger {
    background: var(--color-danger-light);
    color: #991b1b;
}

.badge-warning {
    background: var(--color-warning-light);
    color: #92400e;
}

/* ===================================
   LEGENDE
   =================================== */
.legend {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--color-gray-50);
    border-radius: var(--radius-md);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 0.875rem;
    color: var(--color-gray-600);
}

.legend-color {
    width: 16px;
    height: 16px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-gray-300);
}

.legend-color.checked {
    background: var(--color-success);
}

.legend-color.weekend {
    background: var(--color-weekend);
}

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

/* ===================================
   LOADING SPINNER
   =================================== */
.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--color-gray-200);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.loading-overlay {
    position: fixed;
    inset: 0;
    background: rgba(255, 255, 255, 0.9);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-md);
    z-index: 9999;
}

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

.text-primary { color: var(--color-primary); }
.text-success { color: var(--color-success); }
.text-danger { color: var(--color-danger); }
.text-muted { color: var(--color-gray-500); }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

.d-flex { display: flex; }
.flex-column { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.align-center { align-items: center; }
.justify-between { justify-content: space-between; }
.justify-center { justify-content: center; }
.gap-1 { gap: var(--spacing-sm); }
.gap-2 { gap: var(--spacing-md); }
.gap-3 { gap: var(--spacing-lg); }

.hidden { display: none !important; }
.visible { display: block; }

/* ===================================
   RESPONSIVE DESIGN
   =================================== */
@media (max-width: 768px) {
    .nav {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--color-white);
        flex-direction: column;
        padding: var(--spacing-md);
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-normal);
        z-index: 99;
    }
    
    .nav.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-mobile-toggle {
        display: flex;
    }
    
    .nav-link {
        padding: var(--spacing-md);
        border-radius: var(--radius-md);
    }
    
    .calendar-day {
        min-height: 40px;
    }
    
    .day-number {
        font-size: 0.8125rem;
    }
    
    .calendar-day.checked::after {
        font-size: 0.625rem;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .stat-value {
        font-size: 1.5rem;
    }
    
    .view-switcher {
        width: 100%;
    }
    
    .modal {
        max-width: 100%;
        margin: var(--spacing-md);
        max-height: calc(100vh - 2rem);
    }
    
    .tabs {
        padding-bottom: var(--spacing-sm);
    }
    
    .table th,
    .table td {
        padding: var(--spacing-xs) var(--spacing-sm);
        font-size: 0.875rem;
    }
}

@media (max-width: 480px) {
    :root {
        font-size: 14px;
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .card-body,
    .card-header,
    .card-footer {
        padding: var(--spacing-md);
    }
    
    .calendar-header {
        flex-direction: column;
        gap: var(--spacing-sm);
        text-align: center;
    }
    
    .calendar-weekday {
        padding: var(--spacing-xs);
        font-size: 0.625rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-sm);
    }
    
    .stat-card {
        padding: var(--spacing-md);
    }
    
    .btn {
        padding: var(--spacing-sm) var(--spacing-md);
        font-size: 0.875rem;
    }
    
    .legend {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
}

/* ===================================
   PRINT STYLES
   =================================== */
@media print {
    .header,
    .nav,
    .btn,
    .view-switcher,
    .modal-overlay {
        display: none !important;
    }
    
    body {
        background: white;
    }
    
    .card {
        box-shadow: none;
        border: 1px solid #ddd;
    }
}

/* ===================================
   DARK MODE (optional)
   =================================== */
@media (prefers-color-scheme: dark) {
    /* Dark mode kann bei Bedarf aktiviert werden */
}