/* ============================================
   Modern Design System - CollSched
   Clean, accessible, and user-friendly theme
   ============================================ */

:root {
    /* Color Palette - Modern & Accessible */
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-tertiary: #1a1a24;
    --bg-elevated: #1f1f2e;
    --bg-card: #252536;
    --bg-input: #1a1a24;
    --bg-hover: #2a2a3a;
    
    /* Text Colors */
    --text-primary: #ffffff;
    --text-secondary: #b4b4c8;
    --text-tertiary: #8a8a9e;
    --text-muted: #6a6a7e;
    
    /* Accent Colors - Modern Gradient */
    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #ec4899 100%);
    --accent-gradient-hover: linear-gradient(135deg, #818cf8 0%, #a78bfa 50%, #f472b6 100%);
    --accent-soft: rgba(99, 102, 241, 0.15);
    --accent-border: rgba(99, 102, 241, 0.3);
    
    /* Status Colors */
    --success: #10b981;
    --success-bg: rgba(16, 185, 129, 0.1);
    --warning: #f59e0b;
    --warning-bg: rgba(245, 158, 11, 0.1);
    --error: #ef4444;
    --error-bg: rgba(239, 68, 68, 0.1);
    --info: #3b82f6;
    --info-bg: rgba(59, 130, 246, 0.1);
    
    /* Borders & Shadows */
    --border-color: rgba(255, 255, 255, 0.08);
    --border-color-hover: rgba(255, 255, 255, 0.15);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.6);
    --shadow-glow: 0 0 24px rgba(99, 102, 241, 0.3);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --page-gutter: clamp(1rem, 4vw, 2.5rem);
    --page-vertical: clamp(2rem, 6vw, 4rem);
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-full: 9999px;
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    --font-mono: 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', monospace;
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================
   Reset & Base Styles
   ============================================ */

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

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    background-image: 
        radial-gradient(circle at 20% 30%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(139, 92, 246, 0.08) 0%, transparent 50%),
        radial-gradient(circle at 40% 80%, rgba(236, 72, 153, 0.05) 0%, transparent 50%);
    min-height: 100vh;
    overflow-x: hidden;
}

/* ============================================
   Typography
   ============================================ */

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    color: var(--text-primary);
    margin: 0;
}

p {
    margin: 0;
    color: var(--text-secondary);
}

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

a:hover {
    color: var(--accent-secondary);
    text-decoration: underline;
}

a:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ============================================
   Layout Components
   ============================================ */

.app-shell {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.app-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(10, 10, 15, 0.85);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-md) var(--page-gutter);
    transition: background var(--transition-base), border-color var(--transition-base);
}

.app-header-main {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.app-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 600;
    font-size: 1.125rem;
    color: var(--text-primary);
    text-decoration: none;
}

.logo-image {
    width: 40px;
    height: 40px;
    object-fit: contain;
    display: block;
    flex-shrink: 0;
}

.logo-text {
    font-weight: 600;
    letter-spacing: -0.01em;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.logo-separator {
    color: var(--text-tertiary);
    font-weight: 400;
}

.logo-username {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95em;
}

.app-nav {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: var(--bg-elevated);
    border-radius: var(--radius-full);
    padding: var(--spacing-xs);
    border: 1px solid var(--border-color);
}

.app-nav a {
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--transition-fast);
    position: relative;
}

.app-nav a:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
    text-decoration: none;
}

.app-nav a.active {
    background: var(--accent-gradient);
    color: var(--text-primary);
    box-shadow: var(--shadow-md);
    font-weight: 600;
}

.nav-toggle {
    display: none;
    position: relative;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    padding: var(--spacing-xs);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    background: var(--bg-elevated);
    color: var(--text-primary);
    cursor: pointer;
    transition: background var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
}

.nav-toggle:hover {
    background: var(--bg-hover);
    border-color: var(--border-color-hover);
}

.nav-toggle-bar {
    width: 20px;
    height: 2px;
    border-radius: 999px;
    background: currentColor;
    transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-of-type(1) {
    transform: translateY(6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-of-type(2) {
    opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-of-type(3) {
    transform: translateY(-6px) rotate(-45deg);
}

.nav-toggle-label {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.nav-logout-form {
    display: inline-flex;
    margin: 0;
    padding: 0;
}

.nav-logout-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 500;
    background: linear-gradient(135deg, #ef4444 0%, #dc2626 50%, #b91c1c 100%);
    border: none;
    color: var(--text-primary);
    text-decoration: none;
    transition: all var(--transition-fast);
    cursor: pointer;
    position: relative;
    font-family: inherit;
    box-shadow: var(--shadow-md);
}

.nav-logout-btn:hover {
    background: linear-gradient(135deg, #f87171 0%, #ef4444 50%, #dc2626 100%);
    color: var(--text-primary);
    box-shadow: var(--shadow-lg);
    text-decoration: none;
    transform: translateY(-1px);
}

.nav-logout-btn:active {
    background: linear-gradient(135deg, #dc2626 0%, #b91c1c 50%, #991b1b 100%);
    transform: translateY(0);
}

.app-header-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
    margin-top: var(--spacing-sm);
    font-size: 0.875rem;
    flex-wrap: wrap;
}

.user-email {
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    background: var(--bg-elevated);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    font-weight: 500;
    font-size: 0.875rem;
}

.app-main {
    flex: 1;
    padding: var(--page-vertical) var(--page-gutter);
    display: flex;
    justify-content: center;
    width: 100%;
}

.app-footer {
    padding: var(--page-gutter);
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-muted);
    border-top: 1px solid var(--border-color);
    background: var(--bg-secondary);
    margin-top: auto;
}

.page {
    width: 100%;
    max-width: 1200px;
    animation: fadeIn 0.4s ease-out;
}

.page-auth {
    max-width: 520px;
    margin: auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xl);
    text-align: center;
    min-height: 100%;
}

.page-auth .page-header {
    width: 100%;
    margin-bottom: 0;
}

.page-auth .page-title-row {
    justify-content: center;
}

.page-auth .page-title {
    justify-content: center;
    text-align: center;
}

.page-auth .page-subtitle {
    margin: 0 auto;
    max-width: 34rem;
}

.page-auth .form-card {
    width: 100%;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.page-header {
    margin-bottom: var(--spacing-xl);
}

.page-title-row {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    flex-wrap: wrap;
}

.page-title {
    font-size: 2rem;
    font-weight: 700;
    line-height: 1.2;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    color: var(--text-primary);
}

.pill-gradient {
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background: var(--accent-gradient);
    color: var(--text-primary);
    box-shadow: var(--shadow-sm);
    white-space: nowrap;
}

.page-subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-top: var(--spacing-sm);
}

/* ============================================
   Card Components
   ============================================ */

.card {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-xl);
    transition: all var(--transition-base);
}

.card:hover {
    border-color: var(--border-color-hover);
    box-shadow: var(--shadow-xl);
}

.card-section-title {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--spacing-lg);
}

/* ============================================
   Grid Layouts
   ============================================ */

.grid-week {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-md);
}

.grid-week-modern {
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: var(--spacing-lg);
}

.summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

@media (max-width: 960px) {
    .app-header-main {
        align-items: stretch;
    }

    .nav-toggle {
        display: inline-flex;
        margin-left: auto;
        align-self: flex-end;
    }

    .app-nav {
        display: none;
        width: 100%;
        flex-direction: column;
        gap: var(--spacing-sm);
        background: var(--bg-elevated);
        border-radius: var(--radius-lg);
        padding: var(--spacing-md);
        border: 1px solid var(--border-color);
        box-shadow: var(--shadow-md);
        margin-top: var(--spacing-md);
    }

    .app-nav.is-open {
        display: flex;
    }

    .app-nav a {
        width: 100%;
        justify-content: center;
    }

    .nav-logout-form {
        width: 100%;
    }

    .nav-logout-btn {
        width: 100%;
        justify-content: center;
    }
}

/* ============================================
   Day Cards
   ============================================ */

.day-card {
    position: relative;
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    display: block;
}

.day-card::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: inherit;
    padding: 1px;
    background: var(--accent-gradient);
    opacity: 0;
    transition: opacity var(--transition-base);
    pointer-events: none;
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
}

.day-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
    border-color: var(--accent-border);
}

.day-card:hover::before {
    opacity: 1;
}

.day-card-modern {
    display: grid;
    gap: var(--spacing-md);
}

.day-name-row {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--spacing-md);
}

.day-name {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.day-count {
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.day-chip {
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 500;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    white-space: nowrap;
}

.day-preview {
    margin-top: var(--spacing-sm);
}

.day-preview-item {
    font-size: 0.875rem;
    color: var(--text-secondary);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.day-preview-item:last-child {
    margin-bottom: 0;
}

.day-preview-item .dot {
    display: inline-block;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--accent-gradient);
    margin-right: var(--spacing-sm);
    flex-shrink: 0;
}

.day-empty {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-style: italic;
}

/* ============================================
   Buttons
   ============================================ */

button,
.btn {
    border-radius: var(--radius-md);
    border: none;
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 0.875rem;
    font-weight: 500;
    font-family: inherit;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    white-space: nowrap;
    position: relative;
    overflow: hidden;
}

button:focus-visible,
.btn:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

.btn-primary {
    background: var(--accent-gradient);
    color: var(--text-primary);
    box-shadow: var(--shadow-md);
    font-weight: 600;
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    background: var(--accent-gradient-hover);
    text-decoration: none;
    color: var(--text-primary);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-ghost {
    background: var(--bg-elevated);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.btn-ghost:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
    border-color: var(--border-color-hover);
    text-decoration: none;
}

.btn-danger {
    background: var(--error-bg);
    color: var(--error);
    border: 1px solid rgba(239, 68, 68, 0.3);
}

.btn-danger:hover {
    background: rgba(239, 68, 68, 0.2);
    border-color: rgba(239, 68, 68, 0.5);
    color: #ff6b6b;
    text-decoration: none;
}

.inline-form {
    display: inline;
}

/* ============================================
   Forms
   ============================================ */

.form-card {
    max-width: 480px;
    margin-inline: auto;
}

.form-grid {
    display: grid;
    gap: var(--spacing-lg);
}

.field {
    display: grid;
    gap: var(--spacing-sm);
}

.label-row {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: var(--spacing-md);
}

label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.field-help {
    font-size: 0.75rem;
    color: var(--text-muted);
    line-height: 1.5;
}

input[type="text"],
input[type="email"],
input[type="password"],
input[type="time"],
input[type="datetime-local"],
select,
textarea {
    width: 100%;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    background: var(--bg-input);
    color: var(--text-primary);
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
    font-family: inherit;
    outline: none;
    transition: all var(--transition-fast);
}

input::placeholder,
textarea::placeholder {
    color: var(--text-muted);
}

input:hover,
select:hover,
textarea:hover {
    border-color: var(--border-color-hover);
}

input:focus,
select:focus,
textarea:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-soft);
    background: var(--bg-card);
}

.time-input {
    background: var(--bg-card);
    border-color: var(--accent-border);
    font-weight: 500;
    letter-spacing: 0.02em;
}

.time-input:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-soft), var(--shadow-md);
}

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

/* ============================================
   Messages & Alerts
   ============================================ */

.error {
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    background: var(--error-bg);
    color: var(--error);
    border: 1px solid rgba(239, 68, 68, 0.3);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-lg);
}

.success {
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    background: var(--success-bg);
    color: var(--success);
    border: 1px solid rgba(16, 185, 129, 0.3);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-lg);
}

.badge-warning {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    border-radius: var(--radius-full);
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background: var(--warning-bg);
    border: 1px solid rgba(245, 158, 11, 0.3);
    color: var(--warning);
}

/* ============================================
   Class & Countdown Lists
   ============================================ */

.class-row {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    transition: all var(--transition-fast);
    align-items: center;
}

.class-row:hover {
    background: var(--bg-card);
    border-color: var(--border-color-hover);
    box-shadow: var(--shadow-md);
}

.class-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.class-meta {
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.class-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.countdown-list {
    display: grid;
    gap: var(--spacing-md);
}

.countdown-card {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
    gap: var(--spacing-lg);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    transition: all var(--transition-base);
    align-items: center;
}

.countdown-card:hover {
    background: var(--bg-card);
    border-color: var(--accent-border);
    box-shadow: var(--shadow-md);
}

.countdown-time {
    font-variant-numeric: tabular-nums;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.2;
    margin-bottom: var(--spacing-xs);
}

.countdown-label {
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.countdown-actions {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    margin-top: var(--spacing-sm);
}

/* ============================================
   Stats & Summary Cards
   ============================================ */

.stat-card {
    display: grid;
    gap: var(--spacing-md);
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

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

.stat-top {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: var(--spacing-md);
}

.stat-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
}

.stat-bottom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
    color: var(--text-secondary);
    font-size: 0.875rem;
    flex-wrap: wrap;
}

.time-pill {
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 500;
    background: var(--bg-card);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    white-space: nowrap;
}

.stack-sm {
    display: grid;
    gap: var(--spacing-md);
}

/* ============================================
   Modal & Overlay
   ============================================ */

.confirm-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: var(--spacing-lg);
    animation: fadeIn var(--transition-base);
}

.confirm-dialog {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-xl);
    max-width: 480px;
    width: 100%;
    padding: var(--spacing-xl);
    animation: slideUp var(--transition-base);
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.confirm-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.confirm-text {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.confirm-actions {
    display: flex;
    justify-content: flex-end;
    gap: var(--spacing-md);
}

/* ============================================
   Utility Classes
   ============================================ */

.link-subtle {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    text-decoration: underline;
    text-decoration-style: dotted;
    text-underline-offset: 3px;
    transition: color var(--transition-fast);
}

.link-subtle:hover {
    color: var(--accent-primary);
    text-decoration-style: solid;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ============================================
   Responsive Design
   ============================================ */

@media (max-width: 768px) {
    .app-header-main {
        flex-direction: column;
        align-items: stretch;
        gap: var(--spacing-md);
    }
    
    .page-header {
        text-align: center;
    }
    
    .page-title {
        font-size: clamp(1.5rem, 6vw, 1.75rem);
    }
    
    .page-subtitle {
        font-size: 0.95rem;
    }
    
    .page-title-row {
        flex-direction: column;
        align-items: center;
    }
    
    .grid-week,
    .grid-week-modern {
        grid-template-columns: 1fr;
    }
    
    .summary-grid {
        grid-template-columns: 1fr;
    }
    
    .countdown-card {
        grid-template-columns: 1fr;
    }
    
    .class-row {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .class-actions {
        justify-content: flex-start;
    }
    
    .stat-bottom {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .confirm-dialog {
        margin: var(--spacing-md);
    }
}

@media (max-width: 480px) {
    .page-title {
        font-size: 1.25rem;
    }
    
    .card {
        padding: var(--spacing-lg);
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .confirm-actions {
        flex-direction: column;
    }
    
    .confirm-actions .btn {
        width: 100%;
    }
}

@media (min-width: 1400px) {
    .page {
        max-width: 1320px;
    }
    
    .summary-grid {
        grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    }
    
    .grid-week-modern {
        grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    }
}

/* ============================================
   Tables
   ============================================ */

.table-wrapper {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

.table thead {
    background: var(--bg-elevated);
    border-bottom: 2px solid var(--border-color);
}

.table th {
    padding: var(--spacing-md);
    text-align: left;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
}

.table tbody tr {
    border-bottom: 1px solid var(--border-color);
    transition: background var(--transition-fast);
}

.table tbody tr:hover {
    background: var(--bg-elevated);
}

.table td {
    padding: var(--spacing-md);
    color: var(--text-primary);
}

.table td:first-child {
    font-weight: 500;
    color: var(--text-secondary);
    font-variant-numeric: tabular-nums;
}

/* ============================================
   Checkboxes & Radio Buttons
   ============================================ */

.checkbox-row {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    font-size: 0.875rem;
    color: var(--text-secondary);
    user-select: none;
}

.checkbox-row input[type="checkbox"],
.checkbox-row input[type="radio"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--accent-primary);
    flex-shrink: 0;
}

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

.checkbox-row input[type="checkbox"]:focus,
.checkbox-row input[type="radio"]:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
    border-radius: 3px;
}

input[type="checkbox"],
input[type="radio"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--accent-primary);
}

input[type="checkbox"]:focus,
input[type="radio"]:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
    border-radius: 3px;
}

/* ============================================
   Readonly Inputs
   ============================================ */

input[readonly],
textarea[readonly] {
    background: var(--bg-secondary);
    color: var(--text-tertiary);
    cursor: not-allowed;
    opacity: 0.7;
}

input[readonly]:focus,
textarea[readonly]:focus {
    border-color: var(--border-color);
    box-shadow: none;
}

/* ============================================
   Print Styles
   ============================================ */

@media print {
    .app-header,
    .app-footer,
    .btn,
    .class-actions,
    .countdown-actions {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .card {
        border: 1px solid #ccc;
        box-shadow: none;
    }
}