/**
 * EWU Schedule Builder - Design System
 * Based on style guide reference
 *
 * Usage: Include this before page-specific CSS
 * <link rel="stylesheet" href="../css/design-system.css">
 */

/* ============================================
   CSS VARIABLES - COLOR PALETTE
   ============================================ */
:root {
    /* EWU Brand Colors */
    --ewu-red: #a10022;
    --ewu-red-dark: #8b001d;
    --ewu-red-light: #c91a3d;
    --ewu-black: #1a1a1b;
    
    /* Primary Gradient */
    --primary-gradient: linear-gradient(135deg, #a10022 0%, #760019 100%);
    --secondary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    
    /* Status Colors */
    --color-info: #168FFF;
    --color-success: #22c55e;
    --color-warning: #f59e0b;
    --color-error: #ef4444;

    /* Content Colors (Light Mode) */
    --color-content-1: #1a1a1b;
    --color-content-2: #4a5568;
    --color-content-3: #718096;
    --color-icons: #a0aec0;

    /* UI Colors */
    --color-border: #e2e8f0;
    --color-background-1: #f7fafc;
    --color-background-2: #FFFFFF;
    --color-background-elevated: rgba(255, 255, 255, 0.95);

    /* Accent Colors (for charts/data viz) */
    --color-accent-blue: #168FFF;
    --color-accent-green: #22c55e;
    --color-accent-yellow: #f59e0b;
    --color-accent-red: #ef4444;
    --color-accent-purple: #764ba2;
    --color-accent-teal: #14b8a6;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 25px 80px rgba(0, 0, 0, 0.15);

    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-xl: 20px;
    --radius-2xl: 24px;

    /* Spacing Scale */
    --space-1: 4px;
    --space-2: 8px;
    --space-3: 12px;
    --space-4: 16px;
    --space-5: 20px;
    --space-6: 24px;
    --space-8: 32px;
    --space-10: 40px;
    --space-12: 48px;
    
    /* Transitions */
    --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    font-size: 14px;
    line-height: 1.5;
    color: var(--color-content-1);
    background: var(--color-background-1);
}

h1, .h1 {
    font-size: 32px;
    font-weight: 500;
    line-height: 110%;
    color: var(--color-content-1);
    margin: 0 0 var(--space-4) 0;
}

h2, .h2 {
    font-size: 24px;
    font-weight: 500;
    line-height: 110%;
    color: var(--color-content-1);
    margin: 0 0 var(--space-3) 0;
}

h3, .h3 {
    font-size: 20px;
    font-weight: 500;
    line-height: 110%;
    color: var(--color-content-1);
    margin: 0 0 var(--space-3) 0;
}

h4, .h4 {
    font-size: 16px;
    font-weight: 500;
    line-height: 110%;
    color: var(--color-content-1);
    margin: 0 0 var(--space-2) 0;
}

h5, .h5 {
    font-size: 14px;
    font-weight: 500;
    line-height: 110%;
    color: var(--color-content-2);
    margin: 0 0 var(--space-2) 0;
}

.text-sm { font-size: 13px; }
.text-xs { font-size: 12px; }
.text-muted { color: var(--color-content-3); }
.text-success { color: var(--color-success); }
.text-warning { color: var(--color-warning); }
.text-error { color: var(--color-error); }
.text-info { color: var(--color-info); }

/* ============================================
   LAYOUT COMPONENTS
   ============================================ */

/* Page Container */
.ds-page {
    max-width: 1600px;
    margin: 0 auto;
    padding: var(--space-6);
}

/* Page Header */
.ds-page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-6);
    padding-bottom: var(--space-4);
    border-bottom: 1px solid var(--color-border);
}

.ds-page-header h1 {
    margin: 0;
}

.ds-back-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    color: var(--color-content-2);
    text-decoration: none;
    font-size: 14px;
    margin-bottom: var(--space-3);
}

.ds-back-link:hover {
    color: var(--color-info);
}

/* Grid Layout */
.ds-grid {
    display: grid;
    gap: var(--space-6);
}

.ds-grid-2 { grid-template-columns: repeat(2, 1fr); }
.ds-grid-3 { grid-template-columns: repeat(3, 1fr); }
.ds-grid-4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 1024px) {
    .ds-grid-4 { grid-template-columns: repeat(2, 1fr); }
    .ds-grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .ds-grid-4, .ds-grid-3, .ds-grid-2 { grid-template-columns: 1fr; }
}

/* ============================================
   CARDS
   ============================================ */

/* Base Card */
.ds-card {
    background: var(--color-background-2);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    box-shadow: var(--shadow-sm);
}

.ds-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-4);
}

.ds-card-title {
    font-size: 16px;
    font-weight: 500;
    color: var(--color-content-1);
    margin: 0;
}

.ds-card-subtitle {
    font-size: 13px;
    color: var(--color-content-3);
    margin: var(--space-1) 0 0 0;
}

/* Stat Card */
.ds-stat-card {
    background: var(--color-background-2);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-5);
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.ds-stat-card .stat-label {
    font-size: 13px;
    color: var(--color-content-3);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.ds-stat-card .stat-value {
    font-size: 28px;
    font-weight: 600;
    color: var(--color-content-1);
}

.ds-stat-card .stat-change {
    font-size: 13px;
    display: flex;
    align-items: center;
    gap: var(--space-1);
}

.ds-stat-card .stat-change.positive { color: var(--color-success); }
.ds-stat-card .stat-change.negative { color: var(--color-error); }

.ds-stat-card.accent-blue { border-left: 4px solid var(--color-info); }
.ds-stat-card.accent-green { border-left: 4px solid var(--color-success); }
.ds-stat-card.accent-yellow { border-left: 4px solid var(--color-warning); }
.ds-stat-card.accent-red { border-left: 4px solid var(--color-error); }

/* Status Indicator */
.ds-status {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    font-size: 13px;
}

.ds-status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--color-content-3);
}

.ds-status-dot.success { background: var(--color-success); }
.ds-status-dot.warning { background: var(--color-warning); }
.ds-status-dot.error { background: var(--color-error); }
.ds-status-dot.info { background: var(--color-info); }

/* ============================================
   BUTTONS
   ============================================ */
.ds-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-5);
    font-size: 14px;
    font-weight: 600;
    border-radius: var(--radius-md);
    border: 1px solid transparent;
    cursor: pointer;
    transition: all var(--transition-normal);
    text-decoration: none;
}

.ds-btn:focus-visible {
    outline: 2px solid var(--ewu-red);
    outline-offset: 2px;
}

.ds-btn-primary {
    background: var(--ewu-red);
    color: white;
    border-color: var(--ewu-red);
    box-shadow: 0 4px 14px rgba(161, 0, 34, 0.25);
}

.ds-btn-primary:hover {
    background: var(--ewu-red-dark);
    border-color: var(--ewu-red-dark);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(161, 0, 34, 0.35);
}

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

.ds-btn-secondary {
    background: white;
    color: var(--color-content-1);
    border-color: var(--color-border);
}

.ds-btn-secondary:hover {
    background: var(--color-background-1);
    border-color: var(--color-content-3);
}

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

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

.ds-btn-sm {
    padding: var(--space-1) var(--space-3);
    font-size: 13px;
}

.ds-btn-lg {
    padding: var(--space-3) var(--space-6);
    font-size: 16px;
}

.ds-btn-icon {
    width: 32px;
    height: 32px;
    padding: 0;
    border-radius: var(--radius-md);
}

/* ============================================
   TABLES
   ============================================ */
.ds-table-container {
    overflow-x: auto;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-background-2);
}

.ds-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}

.ds-table th {
    text-align: left;
    padding: var(--space-3) var(--space-4);
    font-weight: 500;
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--color-content-3);
    background: var(--color-background-1);
    border-bottom: 1px solid var(--color-border);
}

.ds-table td {
    padding: var(--space-3) var(--space-4);
    border-bottom: 1px solid var(--color-border);
    color: var(--color-content-1);
}

.ds-table tr:last-child td {
    border-bottom: none;
}

.ds-table tr:hover td {
    background: var(--color-background-1);
}

.ds-table .actions {
    display: flex;
    gap: var(--space-2);
}

/* ============================================
   FORMS
   ============================================ */
.ds-form-group {
    margin-bottom: var(--space-4);
}

.ds-label {
    display: block;
    font-size: 13px;
    font-weight: 500;
    color: var(--color-content-2);
    margin-bottom: var(--space-2);
}

.ds-input,
.ds-select,
.ds-textarea {
    width: 100%;
    padding: var(--space-2) var(--space-3);
    font-size: 14px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: white;
    color: var(--color-content-1);
    transition: border-color 0.2s, box-shadow 0.2s;
}

.ds-input:focus,
.ds-select:focus,
.ds-textarea:focus {
    outline: none;
    border-color: var(--color-info);
    box-shadow: 0 0 0 3px rgba(22, 143, 255, 0.1);
}

.ds-input::placeholder {
    color: var(--color-content-3);
}

.ds-select {
    cursor: pointer;
}

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

/* ============================================
   TABS
   ============================================ */
.ds-tabs {
    display: flex;
    gap: var(--space-1);
    border-bottom: 1px solid var(--color-border);
    margin-bottom: var(--space-6);
}

.ds-tab {
    padding: var(--space-3) var(--space-4);
    font-size: 14px;
    font-weight: 500;
    color: var(--color-content-3);
    background: none;
    border: none;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    margin-bottom: -1px;
    transition: all 0.2s;
}

.ds-tab:hover {
    color: var(--color-content-1);
}

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

.ds-tab-content {
    display: none;
}

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

/* ============================================
   MODALS
   ============================================ */
.ds-modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.2s, visibility 0.2s;
}

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

.ds-modal {
    background: white;
    border-radius: var(--radius-xl);
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
    transform: scale(0.95);
    transition: transform 0.2s;
}

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

.ds-modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-5) var(--space-6);
    border-bottom: 1px solid var(--color-border);
}

.ds-modal-title {
    font-size: 18px;
    font-weight: 500;
    margin: 0;
}

.ds-modal-close {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--color-content-3);
    cursor: pointer;
    border-radius: var(--radius-md);
}

.ds-modal-close:hover {
    background: var(--color-background-1);
    color: var(--color-content-1);
}

.ds-modal-body {
    padding: var(--space-6);
}

.ds-modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: var(--space-3);
    padding: var(--space-4) var(--space-6);
    border-top: 1px solid var(--color-border);
    background: var(--color-background-1);
}

/* ============================================
   BADGES
   ============================================ */
.ds-badge {
    display: inline-flex;
    align-items: center;
    padding: var(--space-1) var(--space-2);
    font-size: 12px;
    font-weight: 500;
    border-radius: var(--radius-sm);
    background: var(--color-background-1);
    color: var(--color-content-2);
}

.ds-badge-success {
    background: #E8F5E9;
    color: #2E7D32;
}

.ds-badge-warning {
    background: #FFF3E0;
    color: #E65100;
}

.ds-badge-error {
    background: #FFEBEE;
    color: #C62828;
}

.ds-badge-info {
    background: #E3F2FD;
    color: #1565C0;
}

/* ============================================
   SEARCH / FILTER BAR
   ============================================ */
.ds-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-4);
    margin-bottom: var(--space-4);
}

.ds-search {
    position: relative;
    flex: 1;
    max-width: 320px;
}

.ds-search input {
    width: 100%;
    padding: var(--space-2) var(--space-3) var(--space-2) var(--space-10);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 14px;
}

.ds-search-icon {
    position: absolute;
    left: var(--space-3);
    top: 50%;
    transform: translateY(-50%);
    color: var(--color-content-3);
}

/* ============================================
   TOAST NOTIFICATIONS
   ============================================ */
.ds-toast {
    position: fixed;
    bottom: var(--space-6);
    right: var(--space-6);
    background: var(--color-content-1);
    color: white;
    padding: var(--space-3) var(--space-5);
    border-radius: var(--radius-md);
    font-size: 14px;
    box-shadow: var(--shadow-lg);
    transform: translateY(100px);
    opacity: 0;
    transition: transform 0.3s, opacity 0.3s;
    z-index: 2000;
}

.ds-toast.active {
    transform: translateY(0);
    opacity: 1;
}

.ds-toast.success {
    background: var(--color-success);
}

.ds-toast.error {
    background: var(--color-error);
}

/* ============================================
   PROGRESS INDICATORS
   ============================================ */
.ds-progress {
    height: 8px;
    background: var(--color-border);
    border-radius: var(--radius-sm);
    overflow: hidden;
}

.ds-progress-bar {
    height: 100%;
    background: var(--color-info);
    border-radius: var(--radius-sm);
    transition: width 0.3s ease;
}

.ds-progress-bar.success { background: var(--color-success); }
.ds-progress-bar.warning { background: var(--color-warning); }
.ds-progress-bar.error { background: var(--color-error); }

/* ============================================
   EMPTY STATES
   ============================================ */
.ds-empty-state {
    text-align: center;
    padding: var(--space-12) var(--space-6);
    color: var(--color-content-3);
}

.ds-empty-state-icon {
    font-size: 48px;
    margin-bottom: var(--space-4);
    opacity: 0.5;
}

.ds-empty-state h3 {
    color: var(--color-content-2);
    margin-bottom: var(--space-2);
}

/* ============================================
   FLOATING ACTION BUTTONS
   ============================================ */
.ds-fab-container {
    position: fixed;
    right: var(--space-6);
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    z-index: 100;
}

.ds-fab {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-5);
    border-radius: var(--radius-lg);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-normal);
    border: none;
    box-shadow: var(--shadow-md);
    white-space: nowrap;
}

.ds-fab:hover {
    transform: translateX(-4px);
    box-shadow: var(--shadow-lg);
}

.ds-fab:active {
    transform: translateX(0);
}

.ds-fab-primary {
    background: var(--color-success);
    color: white;
}

.ds-fab-primary:hover {
    background: #16a34a;
}

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

.ds-fab-warning:hover {
    background: #d97706;
}

.ds-fab-info {
    background: var(--color-info);
    color: white;
}

.ds-fab-info:hover {
    background: #0284c7;
}

.ds-fab-secondary {
    background: var(--color-background-2);
    color: var(--color-content-1);
    border: 1px solid var(--color-border);
}

.ds-fab-secondary:hover {
    background: var(--color-background-1);
    border-color: var(--color-content-3);
}

.ds-fab-icon {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    padding: 0;
}

/* ============================================
   SKELETON LOADING
   ============================================ */
.ds-skeleton {
    background: linear-gradient(90deg, var(--color-border) 25%, var(--color-background-1) 50%, var(--color-border) 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: var(--radius-sm);
}

@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

.ds-skeleton-text {
    height: 16px;
    margin-bottom: var(--space-2);
}

.ds-skeleton-title {
    height: 24px;
    width: 60%;
    margin-bottom: var(--space-3);
}

.ds-skeleton-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
}

/* ============================================
   FOCUS STATES & ACCESSIBILITY
   ============================================ */
*:focus-visible {
    outline: 2px solid var(--ewu-red);
    outline-offset: 2px;
}

.ds-sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* ============================================
   UTILITIES
   ============================================ */
.ds-flex { display: flex; }
.ds-flex-col { flex-direction: column; }
.ds-items-center { align-items: center; }
.ds-justify-between { justify-content: space-between; }
.ds-gap-2 { gap: var(--space-2); }
.ds-gap-3 { gap: var(--space-3); }
.ds-gap-4 { gap: var(--space-4); }
.ds-gap-6 { gap: var(--space-6); }
.ds-mt-2 { margin-top: var(--space-2); }
.ds-mt-4 { margin-top: var(--space-4); }
.ds-mt-6 { margin-top: var(--space-6); }
.ds-mb-2 { margin-bottom: var(--space-2); }
.ds-mb-4 { margin-bottom: var(--space-4); }
.ds-mb-6 { margin-bottom: var(--space-6); }
.ds-hidden { display: none; }
.ds-text-center { text-align: center; }
.ds-text-right { text-align: right; }
.ds-font-medium { font-weight: 500; }
.ds-font-semibold { font-weight: 600; }
.ds-font-bold { font-weight: 700; }

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Better focus for keyboard navigation */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}