/* 
 * LearnPro LMS - Main Stylesheet
 * Mobile-First, Modern Design System
 */

:root {
    /* Primary Colors - Deep Ocean Blue */
    --primary-50: #eff6ff;
    --primary-100: #dbeafe;
    --primary-200: #bfdbfe;
    --primary-300: #93c5fd;
    --primary-400: #60a5fa;
    --primary-500: #3b82f6;
    --primary-600: #2563eb;
    --primary-700: #1d4ed8;
    --primary-800: #1e40af;
    --primary-900: #1e3a8a;
    
    /* Accent Colors */
    --accent-purple: #8b5cf6;
    --accent-green: #10b981;
    --accent-orange: #f59e0b;
    --accent-red: #ef4444;
    --accent-pink: #ec4899;
    
    /* Neutrals */
    --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;
    
    /* Semantic Colors */
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --info: #3b82f6;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-display: 'Plus Jakarta Sans', var(--font-sans);
    --font-mono: 'Fira Code', 'Courier New', monospace;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --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);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--gray-800);
    background: var(--gray-50);
    overflow-x: hidden;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.2;
    color: var(--gray-900);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-md);
    color: var(--gray-600);
}

a {
    color: var(--primary-600);
    text-decoration: none;
    transition: color var(--transition);
}

a:hover {
    color: var(--primary-700);
}

/* Container */
.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-xl);
    }
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: 0.625rem 1.25rem;
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius);
    border: none;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    white-space: nowrap;
    outline: none;
}

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

.btn-primary {
    background: var(--primary-600);
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background: var(--primary-700);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

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

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

.btn-success:hover:not(:disabled) {
    background: #059669;
}

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

.btn-danger:hover:not(:disabled) {
    background: #dc2626;
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--primary-600);
    color: var(--primary-600);
}

.btn-outline:hover:not(:disabled) {
    background: var(--primary-600);
    color: white;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.8125rem;
}

.btn-lg {
    padding: 0.875rem 1.75rem;
    font-size: 1rem;
}

.btn-icon {
    padding: 0.625rem;
    aspect-ratio: 1;
}

/* Cards */
.card {
    background: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    overflow: hidden;
    transition: all var(--transition);
}

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

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

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

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

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

.form-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--gray-700);
    margin-bottom: var(--spacing-sm);
}

.form-control {
    width: 100%;
    padding: 0.625rem 1rem;
    font-size: 0.9375rem;
    border: 2px solid var(--gray-300);
    border-radius: var(--radius);
    background: white;
    transition: all var(--transition);
    outline: none;
}

.form-control:focus {
    border-color: var(--primary-500);
    box-shadow: 0 0 0 3px var(--primary-100);
}

.form-control.is-invalid {
    border-color: var(--error);
}

.form-control.is-invalid:focus {
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1);
}

.invalid-feedback {
    display: block;
    font-size: 0.875rem;
    color: var(--error);
    margin-top: var(--spacing-xs);
}

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

select.form-control {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3E%3Cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='m6 8 4 4 4-4'/%3E%3C/svg%3E");
    background-position: right 0.5rem center;
    background-repeat: no-repeat;
    background-size: 1.5em 1.5em;
    padding-right: 2.5rem;
}

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.25rem 0.75rem;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    text-transform: uppercase;
    letter-spacing: 0.025em;
}

.badge-primary { background: var(--primary-100); color: var(--primary-700); }
.badge-success { background: #d1fae5; color: #065f46; }
.badge-warning { background: #fef3c7; color: #92400e; }
.badge-danger { background: #fee2e2; color: #991b1b; }
.badge-info { background: var(--primary-100); color: var(--primary-700); }

/* Alerts */
.alert {
    padding: var(--spacing-md);
    border-radius: var(--radius);
    margin-bottom: var(--spacing-lg);
    border-left: 4px solid;
}

.alert-success {
    background: #d1fae5;
    border-color: var(--success);
    color: #065f46;
}

.alert-warning {
    background: #fef3c7;
    border-color: var(--warning);
    color: #92400e;
}

.alert-danger {
    background: #fee2e2;
    border-color: var(--error);
    color: #991b1b;
}

.alert-info {
    background: var(--primary-100);
    border-color: var(--primary-500);
    color: var(--primary-800);
}

/* Navigation */
.navbar {
    background: white;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) 0;
}

.navbar-brand {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary-600);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.navbar-menu {
    display: none;
    list-style: none;
}

.navbar-menu.active {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: white;
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-lg);
    gap: var(--spacing-sm);
}

.navbar-item {
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--gray-700);
    font-weight: 500;
    border-radius: var(--radius);
    transition: all var(--transition);
}

.navbar-item:hover,
.navbar-item.active {
    background: var(--primary-50);
    color: var(--primary-600);
}

.navbar-toggle {
    display: flex;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
}

@media (min-width: 768px) {
    .navbar-menu {
        display: flex;
        flex-direction: row;
        gap: var(--spacing-sm);
        position: static;
        box-shadow: none;
        padding: 0;
    }
    
    .navbar-toggle {
        display: none;
    }
}

/* Sidebar */
.sidebar {
    position: fixed;
    top: 0;
    left: -280px;
    width: 280px;
    height: 100vh;
    background: white;
    box-shadow: var(--shadow-xl);
    transition: left var(--transition-slow);
    z-index: 2000;
    overflow-y: auto;
}

.sidebar.active {
    left: 0;
}

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

.sidebar-menu {
    list-style: none;
    padding: var(--spacing-md);
}

.sidebar-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    color: var(--gray-700);
    border-radius: var(--radius);
    margin-bottom: var(--spacing-xs);
    transition: all var(--transition);
    cursor: pointer;
}

.sidebar-item:hover,
.sidebar-item.active {
    background: var(--primary-50);
    color: var(--primary-600);
}

.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1999;
}

.sidebar-overlay.active {
    display: block;
}

@media (min-width: 1024px) {
    .sidebar {
        left: 0;
    }
    
    .main-content.with-sidebar {
        margin-left: 280px;
    }
}

/* Grid System */
.row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 calc(-1 * var(--spacing-md));
}

.col {
    flex: 1;
    padding: 0 var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.col-12 { flex: 0 0 100%; max-width: 100%; }
.col-6 { flex: 0 0 50%; max-width: 50%; }
.col-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
.col-3 { flex: 0 0 25%; max-width: 25%; }

@media (max-width: 767px) {
    .col-sm-12 { flex: 0 0 100%; max-width: 100%; }
}

@media (min-width: 768px) and (max-width: 1023px) {
    .col-md-6 { flex: 0 0 50%; max-width: 50%; }
    .col-md-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
}

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

.d-none { display: none !important; }
.d-block { display: block !important; }
.d-flex { display: flex !important; }
.d-inline-flex { display: inline-flex !important; }

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }

.p-1 { padding: var(--spacing-xs); }
.p-2 { padding: var(--spacing-sm); }
.p-3 { padding: var(--spacing-md); }
.p-4 { padding: var(--spacing-lg); }
.p-5 { padding: var(--spacing-xl); }

/* Loading Spinner */
.spinner {
    display: inline-block;
    width: 1.25rem;
    height: 1.25rem;
    border: 2px solid var(--gray-300);
    border-top-color: var(--primary-600);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Progress Bar */
.progress {
    height: 0.5rem;
    background: var(--gray-200);
    border-radius: var(--radius-full);
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-500), var(--primary-600));
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
}

/* Responsive */
@media (max-width: 767px) {
    h1 { font-size: 1.75rem; }
    h2 { font-size: 1.5rem; }
    h3 { font-size: 1.25rem; }
}