/* Modern Learning System - FIXED VERSION */

/* CSS Custom Properties for Modern Design System */
:root {
    /* Modern Color Palette */
    --primary-50: #eff6ff;
    --primary-100: #dbeafe;
    --primary-500: #3b82f6;
    --primary-600: #2563eb;
    --primary-700: #1d4ed8;
    --primary-800: #1e40af;
    --primary-900: #1e3a8a;

    --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;
    --gray-950: #030712;

    --success-50: #f0fdf4;
    --success-500: #22c55e;
    --success-600: #16a34a;

    --warning-50: #fffbeb;
    --warning-500: #f59e0b;
    --warning-600: #d97706;

    --error-50: #fef2f2;
    --error-500: #ef4444;
    --error-600: #dc2626;

    /* Modern Typography */
    --font-family-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-family-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;

    --text-xs: 0.75rem; /* 12px */
    --text-sm: 0.875rem; /* 14px */
    --text-base: 1rem; /* 16px */
    --text-lg: 1.125rem; /* 18px */
    --text-xl: 1.25rem; /* 20px */
    --text-2xl: 1.5rem; /* 24px */
    --text-3xl: 1.875rem; /* 30px */
    --text-4xl: 2.25rem; /* 36px */

    /* Modern Spacing */
    --space-1: 0.25rem; /* 4px */
    --space-2: 0.5rem; /* 8px */
    --space-3: 0.75rem; /* 12px */
    --space-4: 1rem; /* 16px */
    --space-5: 1.25rem; /* 20px */
    --space-6: 1.5rem; /* 24px */
    --space-8: 2rem; /* 32px */
    --space-10: 2.5rem; /* 40px */
    --space-12: 3rem; /* 48px */
    --space-16: 4rem; /* 64px */
    --space-20: 5rem; /* 80px */

    /* Modern Radius */
    --radius-sm: 0.375rem; /* 6px */
    --radius-md: 0.5rem; /* 8px */
    --radius-lg: 0.75rem; /* 12px */
    --radius-xl: 1rem; /* 16px */
    --radius-2xl: 1.5rem; /* 24px */
    --radius-full: 9999px;

    /* Modern Shadows */
    --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);
    --shadow-2xl: 0 25px 50px -12px rgb(0 0 0 / 0.25);

    /* Modern Transitions */
    --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
    :root {
        --background: var(--gray-950);
        --surface: var(--gray-900);
        --surface-hover: var(--gray-800);
        --text-primary: var(--gray-50);
        --text-secondary: var(--gray-300);
        --text-tertiary: var(--gray-400);
        --border: var(--gray-800);
        --border-hover: var(--gray-700);
    }
}

/* Light Mode Default */
:root {
    --background: white;
    --surface: var(--gray-50);
    --surface-hover: var(--gray-100);
    --text-primary: var(--gray-900);
    --text-secondary: var(--gray-600);
    --text-tertiary: var(--gray-500);
    --border: var(--gray-200);
    --border-hover: var(--gray-300);
}

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

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

body {
    font-family: var(--font-family-sans);
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    font-size: var(--text-base);
    transition: background-color var(--transition-base), color var(--transition-base);
    margin: 0;
    padding: 0;
    overflow-x: hidden;
}

/* CRITICAL: Screen Management System - RESTORED */
.screen {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    z-index: 1;
    overflow-y: auto;
}

.screen.active {
    display: block;
}

/* Loading Screen */
#loading {
    background: linear-gradient(135deg, var(--primary-600) 0%, var(--primary-800) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    z-index: 1000;
}

.loading-content {
    text-align: center;
    animation: fadeInUp 0.8s ease-out;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top: 4px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto var(--space-4);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

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

/* Login Screen */
#login {
    background: linear-gradient(135deg, var(--primary-50) 0%, var(--primary-100) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-4);
}

@media (prefers-color-scheme: dark) {
    #login {
        background: linear-gradient(135deg, var(--gray-900) 0%, var(--gray-800) 100%);
    }
}

.auth-container {
    background: var(--background);
    padding: var(--space-8);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-2xl);
    width: 100%;
    max-width: 400px;
    border: 1px solid var(--border);
}

.auth-header {
    text-align: center;
    margin-bottom: var(--space-8);
}

.auth-header h1 {
    font-size: var(--text-3xl);
    font-weight: 700;
    margin-bottom: var(--space-2);
    background: linear-gradient(135deg, var(--primary-600) 0%, var(--primary-800) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.auth-header p {
    color: var(--text-secondary);
    font-size: var(--text-base);
}

.auth-tabs {
    display: flex;
    margin-bottom: var(--space-6);
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: var(--space-1);
}

.tab-btn {
    flex: 1;
    padding: var(--space-3) var(--space-4);
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-weight: 500;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.tab-btn.active {
    background: var(--primary-600);
    color: white;
    box-shadow: var(--shadow-sm);
}

.auth-form {
    display: none;
}

.auth-form.active {
    display: block;
}

/* Main App Screen */
#main {
    background: var(--background);
    display: flex;
    flex-direction: column;
}

/* View Management System - RESTORED */
.view {
    display: none;
    padding: var(--space-6);
    min-height: calc(100vh - 80px);
    overflow-y: auto;
}

.view.active {
    display: block;
}

/* Navigation */
.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4) var(--space-6);
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 50;
    backdrop-filter: blur(20px);
    background: rgba(255, 255, 255, 0.95);
    min-height: 80px;
}

@media (prefers-color-scheme: dark) {
    .navbar {
        background: rgba(17, 24, 39, 0.95);
    }
}

.nav-left h1 {
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--primary-600);
}

.nav-tabs {
    display: flex;
    gap: var(--space-2);
    align-items: center;
}

.nav-tab {
    padding: var(--space-3) var(--space-5);
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
    background: none;
    border: none;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    min-height: 44px;
    display: flex;
    align-items: center;
}

.nav-tab:hover {
    color: var(--text-primary);
    background: var(--surface-hover);
}

.nav-tab.active {
    color: var(--primary-600);
    background: var(--primary-50);
    box-shadow: var(--shadow-sm);
}

@media (prefers-color-scheme: dark) {
    .nav-tab.active {
        background: rgba(59, 130, 246, 0.1);
    }
}

.nav-right {
    display: flex;
    align-items: center;
    gap: var(--space-4);
}

#user-name {
    font-weight: 600;
    color: var(--text-primary);
}

/* Modern Button System */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    border: none;
    border-radius: var(--radius-lg);
    font-family: inherit;
    font-size: var(--text-sm);
    font-weight: 500;
    line-height: 1;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
    position: relative;
    overflow: hidden;
    min-height: 44px; /* iOS touch target */
}

.btn:focus-visible {
    outline: 2px solid var(--primary-500);
    outline-offset: 2px;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    pointer-events: none;
}

/* Primary Button */
.btn-primary {
    background: linear-gradient(135deg, var(--primary-600) 0%, var(--primary-700) 100%);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--primary-700) 0%, var(--primary-800) 100%);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

/* Secondary Button */
.btn-secondary {
    background: var(--surface);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: var(--surface-hover);
    border-color: var(--border-hover);
    box-shadow: var(--shadow-sm);
    transform: translateY(-1px);
}

/* Form Styles */
.form-group {
    margin-bottom: var(--space-6);
}

.form-group label {
    display: block;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: var(--space-2);
    font-size: var(--text-sm);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: var(--space-3) var(--space-4);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    font-size: var(--text-base);
    font-family: inherit;
    background: var(--background);
    color: var(--text-primary);
    transition: all var(--transition-fast);
    min-height: 44px;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-500);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-tertiary);
}

/* Dashboard Grid */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-6);
    margin-bottom: var(--space-8);
}

.stats-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

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

/* AI Extraction Section */
.ai-extraction-section {
    background: var(--surface);
    border-radius: var(--radius-2xl);
    padding: var(--space-8);
    margin-bottom: var(--space-8);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
}

.ai-extraction-header {
    text-align: center;
    margin-bottom: var(--space-8);
}

.ai-extraction-header h3 {
    font-size: var(--text-3xl);
    font-weight: 700;
    margin-bottom: var(--space-3);
    background: linear-gradient(135deg, var(--primary-600) 0%, var(--primary-800) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.ai-extraction-header p {
    color: var(--text-secondary);
    font-size: var(--text-lg);
    max-width: 600px;
    margin: 0 auto;
}

/* File Upload Area */
.ai-file-input,
.file-upload-area {
    border: 2px dashed var(--border);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
    text-align: center;
    transition: all var(--transition-base);
    background: var(--surface);
    position: relative;
    overflow: hidden;
    margin-bottom: var(--space-6);
}

.file-upload-area:hover,
.file-upload-area.drag-over {
    border-color: var(--primary-500);
    background: var(--primary-50);
    transform: scale(1.02);
}

@media (prefers-color-scheme: dark) {
    .file-upload-area:hover,
    .file-upload-area.drag-over {
        background: rgba(59, 130, 246, 0.05);
    }
}

/* AI Options and Results */
.ai-options {
    opacity: 0;
    transform: translateY(20px);
    transition: all var(--transition-slow);
    pointer-events: none;
}

.ai-options.show {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
}

.ai-buttons {
    display: flex;
    gap: var(--space-4);
    justify-content: center;
    flex-wrap: wrap;
}

.ai-results {
    opacity: 0;
    transform: translateY(20px);
    transition: all var(--transition-slow);
    margin-top: var(--space-8);
    pointer-events: none;
}

.ai-results.show {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
}

/* Mobile Navigation */
.mobile-nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: var(--text-2xl);
    color: var(--text-primary);
    cursor: pointer;
    padding: var(--space-2);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    min-height: 44px;
    min-width: 44px;
}

.mobile-nav-toggle:hover {
    background: var(--surface-hover);
}

/* Responsive Design */
@media (max-width: 768px) {
    .navbar {
        flex-wrap: wrap;
        padding: var(--space-3) var(--space-4);
    }

    .nav-tabs {
        display: none;
        width: 100%;
        flex-direction: column;
        margin-top: var(--space-4);
        padding-top: var(--space-4);
        border-top: 1px solid var(--border);
    }

    .nav-tabs.show {
        display: flex;
    }

    .mobile-nav-toggle {
        display: block;
    }

    .view {
        padding: var(--space-4);
    }

    .dashboard-grid {
        grid-template-columns: 1fr;
        gap: var(--space-4);
    }

    .ai-extraction-section {
        padding: var(--space-6);
    }

    .ai-extraction-header h3 {
        font-size: var(--text-2xl);
    }

    .ai-buttons {
        flex-direction: column;
        align-items: stretch;
    }

    .auth-container {
        padding: var(--space-6);
        margin: var(--space-4);
    }
}

@media (max-width: 480px) {
    .ai-extraction-header h3 {
        font-size: var(--text-xl);
    }

    .auth-container {
        padding: var(--space-4);
    }

    .view {
        padding: var(--space-3);
    }
}

/* Print styles */
@media print {
    .navbar,
    .mobile-nav-toggle {
        display: none !important;
    }

    body {
        background: white !important;
        color: black !important;
    }
}
/* Emergency CSS Animation to hide loading screen */
@keyframes hideLoading {
    0% { opacity: 1; }
    95% { opacity: 1; }
    100% { opacity: 0; visibility: hidden; }
}

#loading.active {
    animation: hideLoading 3s ease-out forwards;
}

/* Show login screen after loading */
@keyframes showLogin {
    0% { opacity: 0; visibility: hidden; }
    95% { opacity: 0; visibility: hidden; }
    100% { opacity: 1; visibility: visible; }
}

#login {
    animation: showLogin 4s ease-out forwards;
}