/**
 * EduPractice - Main Stylesheet
 * Enhanced with modern CSS features and performance optimizations
 */

/* CSS Custom Properties for consistent theming */
:root {
    /* New Design Tokens (Option A) */
    --color-primary: #4F46E5; /* Indigo 600 */
    --color-secondary: #A7F3D0; /* Mint 300 */
    --color-sky: #38BDF8; /* Sky 400 */
    --color-lavender: #A78BFA; /* Lavender 400 */
    --color-success: #10B981;
    --color-warning: #F59E0B;
    --color-danger: #EF4444;
    --color-info: #0EA5E9;

    --neutral-bg: #F8FAFC;         /* page bg */
    --neutral-surface: #FFFFFF;    /* cards/modals */
    --neutral-text: #0F172A;       /* primary text */
    --neutral-text-subtle: #475569; /* secondary text */

    --gradient-primary: linear-gradient(135deg, #4F46E5, #8B5CF6, #38BDF8);
    --gradient-primary-90: linear-gradient(90deg, #4F46E5, #8B5CF6, #38BDF8);

    /* Legacy Brand Colors (back-compat) */
    --edu-blue: #2563eb;
    --edu-light-blue: #3b82f6;
    --edu-dark-blue: #1e40af;
    --edu-green: #10b981;
    --edu-orange: #f59e0b;
    --edu-purple: #8b5cf6;
    --edu-pink: #ec4899;
    --edu-indigo: #6366f1;

    /* Neutral Colors (scale) */
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Typography */
    --font-family-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-family-mono: 'JetBrains Mono', 'Fira Code', monospace;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 300ms ease-in-out;
    --transition-slow: 500ms ease-in-out;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
}

/* Base Styles */
* {
    box-sizing: border-box;
}

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

body {
    font-family: var(--font-family-sans);
    line-height: 1.6;
    color: var(--neutral-text);
    background-color: var(--neutral-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Loading States */
.app-loading {
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.app-loaded {
    opacity: 1;
}

/* Enhanced Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.btn:before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left var(--transition-normal);
}

.btn:hover:before {
    left: 100%;
}

.btn-primary {
    background: var(--gradient-primary);
    color: #ffffff;
    box-shadow: var(--shadow-md);
}

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

.btn-secondary {
    background: var(--gray-100);
    color: var(--gray-700);
    border: 1px solid var(--gray-300);
}

.btn-secondary:hover {
    background: var(--gray-200);
    border-color: var(--gray-400);
}

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

.btn-warning {
    background: linear-gradient(135deg, var(--edu-orange), #d97706);
    color: white;
}

.btn-danger {
    background: linear-gradient(135deg, #ef4444, #dc2626);
    color: white;
}

/* Enhanced Card Styles */
.card {
    background: var(--neutral-surface);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-200);
    transition: all var(--transition-normal);
    overflow: hidden;
}

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

.card-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--gray-200);
    background: linear-gradient(135deg, var(--gray-50), var(--neutral-surface));
}

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

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

/* Enhanced Form Styles */
.form-group {
    margin-bottom: var(--spacing-lg);
}

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

.form-input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--gray-300);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: all var(--transition-fast);
    background: white;
}

.form-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

.form-input:invalid {
    border-color: #ef4444;
}

.form-input:valid {
    border-color: var(--edu-green);
}

/* Enhanced Navigation */
.navbar {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--gray-200);
    transition: all var(--transition-normal);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow-md);
}

/* Branded dark navbar variant (for landing and primary pages) */
.navbar--brand {
    background: linear-gradient(90deg, rgba(11, 18, 32, 0.92), rgba(17, 24, 39, 0.92));
    border-bottom: 1px solid rgba(148, 163, 184, 0.15);
    color: #E5E7EB;
}
.navbar--brand a { color: #E5E7EB; }
.navbar--brand a:hover { color: #ffffff; }
.navbar--brand .btn.btn-primary { color: #fff; }
.navbar--brand:after {
    content: '';
    display: block;
    height: 2px;
    background: var(--gradient-primary-90);
}

/* Landing hero visuals */
.hero-surface {
    background: radial-gradient(1200px 600px at 10% -20%, rgba(79,70,229,0.35), transparent 60%),
                radial-gradient(800px 500px at 90% -10%, rgba(56,189,248,0.25), transparent 60%),
                linear-gradient(180deg, #0B1220, #0F172A);
}
.gradient-text {
    background: var(--gradient-primary-90);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}
.soft-glow {
    box-shadow: 0 0 0 1px rgba(148,163,184,0.15), 0 20px 60px rgba(79,70,229,0.25);
}

/* Mock dashboard widgets */
.dashboard-preview { background: rgba(15,23,42,0.9); border: 1px solid rgba(148,163,184,0.12); }
.widget { background: rgba(17,24,39,0.9); border: 1px solid rgba(148,163,184,0.12); border-radius: var(--radius-xl); }

/* Conic progress ring */
.ring {
    --size: 180px;
    --value: 0.75; /* 0..1 */
    width: var(--size);
    height: var(--size);
    border-radius: 50%;
    background:
      conic-gradient(#4F46E5 calc(var(--value)*1turn), rgba(148,163,184,0.15) 0);
    display: grid; place-items: center;
    box-shadow: inset 0 0 40px rgba(0,0,0,0.4);
}
.ring > .ring-inner {
    width: calc(var(--size) - 24px);
    height: calc(var(--size) - 24px);
    border-radius: 50%;
    background: #0F172A;
    display: grid; place-items: center;
    color: #E5E7EB; font-weight: 700; font-size: 1.75rem;
}

.nav-item {
    position: relative;
    transition: all var(--transition-fast);
}

.nav-item:after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--edu-blue);
    transition: width var(--transition-fast);
}

.nav-item:hover:after,
.nav-item.active:after {
    width: 100%;
}

/* Enhanced Dashboard Styles */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

/* Shared Design Utilities for Student Pages */
.glass-effect {
    background: rgba(255, 255, 255, 0.7);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.glass-dark {
    background: rgba(30, 41, 59, 0.7);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.gradient-border {
    background: linear-gradient(white, white) padding-box,
                linear-gradient(90deg, var(--edu-blue), var(--edu-purple)) border-box;
    border: 2px solid transparent;
    border-radius: var(--radius-xl);
}

.gradient-border-light {
    background: linear-gradient(white, white) padding-box,
                linear-gradient(90deg, var(--edu-light-blue), var(--edu-indigo)) border-box;
    border: 2px solid transparent;
    border-radius: var(--radius-xl);
}

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

.cta-primary {
    background: linear-gradient(135deg, var(--edu-blue), var(--edu-light-blue));
    color: #fff;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.cta-primary:hover {
    transform: translateY(-2px) scale(1.01);
    box-shadow: var(--shadow-xl);
}

.cta-secondary {
    background: rgba(255,255,255,0.2);
    color: #fff;
    border-radius: var(--radius-lg);
    backdrop-filter: blur(6px);
}

.badge-pill {
    display: inline-flex;
    align-items: center;
    padding: 0.25rem 0.6rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
}

.icon-tile {
    width: 3rem;
    height: 3rem;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(37, 99, 235, 0.1);
    color: var(--edu-blue);
}

.hover-scale {
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.hover-scale:hover { transform: translateY(-2px) scale(1.02); }

.animate-fade-in { animation: fadeIn 0.5s ease-in-out; }
.animate-slide-up { animation: slideUp 0.3s ease-out; }

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

.stat-card {
    background: white;
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-200);
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.stat-card:before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--edu-blue), var(--edu-purple));
}

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

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.stat-label {
    color: var(--gray-600);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: 0.875rem;
}

/* Progress Bars */
.progress-bar {
    height: 8px;
    background: var(--gray-200);
    border-radius: var(--radius-sm);
    overflow: hidden;
    position: relative;
}

.progress-fill {
    height: 100%;
    background: var(--gradient-primary-90);
    border-radius: var(--radius-sm);
    transition: width var(--transition-slow);
    position: relative;
}

.progress-fill:after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

/* Enhanced Tables */
.table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.table th {
    background: var(--gray-50);
    padding: var(--spacing-md);
    text-align: left;
    font-weight: 600;
    color: var(--gray-700);
    border-bottom: 2px solid var(--gray-200);
}

.table td {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--gray-200);
}

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

/* Enhanced Modals */
.modal {
    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;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.modal.show {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: white;
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    max-width: 500px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    transform: scale(0.9);
    transition: transform var(--transition-normal);
}

.modal.show .modal-content {
    transform: scale(1);
}

/* Enhanced Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes fadeInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.animate-fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}

.animate-fade-in-left {
    animation: fadeInLeft 0.6s ease-out;
}

.animate-fade-in-right {
    animation: fadeInRight 0.6s ease-out;
}

/* Enhanced Loading States */
.loading-spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid var(--gray-300);
    border-radius: 50%;
    border-top-color: var(--edu-blue);
    animation: spin 1s ease-in-out infinite;
}

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

.loading-skeleton {
    background: linear-gradient(90deg, var(--gray-200) 25%, var(--gray-100) 50%, var(--gray-200) 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

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

/* Enhanced Responsive Design */
@media (max-width: 768px) {
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    
    .stat-value {
        font-size: 2rem;
    }
    
    .modal-content {
        width: 95%;
        padding: var(--spacing-lg);
    }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --gray-50: #1f2937;
        --gray-100: #374151;
        --gray-200: #4b5563;
        --gray-300: #6b7280;
        --gray-400: #9ca3af;
        --gray-500: #d1d5db;
        --gray-600: #e5e7eb;
        --gray-700: #f3f4f6;
        --gray-800: #f9fafb;
        --gray-900: #ffffff;
    }
    
    body {
        background-color: var(--gray-900);
        color: var(--gray-100);
    }
    
    .card {
        background: var(--gray-800);
        border-color: var(--gray-700);
    }
    
    .navbar {
        background: rgba(31, 41, 55, 0.95);
        border-color: var(--gray-700);
    }
}

/* Class-based Dark Theme (explicit) */
.theme-dark {
    --neutral-bg: #0B1220;
    --neutral-surface: #111827;
    --neutral-text: #E5E7EB;
    --neutral-text-subtle: #9CA3AF;
    --gradient-primary: linear-gradient(135deg, #4F46E5, #8B5CF6, #22D3EE);
    --gradient-primary-90: linear-gradient(90deg, #4F46E5, #8B5CF6, #22D3EE);
}

/* Sidebar layout skeleton */
.app-layout {
    display: grid;
    grid-template-columns: 260px 1fr;
    gap: var(--spacing-lg);
}
.app-sidebar {
    background: var(--neutral-surface);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
}
.app-sidebar a {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.6rem 0.75rem;
    color: var(--neutral-text-subtle);
    border-radius: var(--radius-md);
    transition: background var(--transition-fast), color var(--transition-fast);
}
.app-sidebar a:hover { background: rgba(79, 70, 229, 0.08); color: var(--neutral-text); }
.app-sidebar a.active { background: var(--color-primary); color: #fff; }

@media (max-width: 1024px) {
    .app-layout { grid-template-columns: 1fr; }
}

/* Print Styles */
@media print {
    .navbar,
    .sidebar,
    .btn,
    .modal {
        display: none !important;
    }
    
    .card {
        box-shadow: none;
        border: 1px solid var(--gray-300);
    }
    
    body {
        background: white;
        color: black;
    }
}

/* Accessibility Enhancements */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles for keyboard navigation */
.btn:focus,
.form-input:focus,
.nav-item:focus {
    outline: 2px solid var(--edu-blue);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .card {
        border: 2px solid var(--gray-800);
    }
    
    .btn {
        border: 2px solid currentColor;
    }
}