/* ===================================
   ENGLISH LEARNING PLATFORM - STYLES
   Theme: Yves Klein Blue
   =================================== */

:root {
    /* Yves Klein Blue Theme */
    --klein-blue: #002FA7;
    --klein-blue-light: #0047FF;
    --klein-blue-dark: #001F6B;
    --klein-blue-ultra: #00238C;
    
    /* Dynamic Text Colors (adjusted by palette) */
    --hero-text-color: #FFFFFF;
    --nav-text-hover: #FFFFFF;
    
    /* Painter Palettes */
    /* Matisse */
    --matisse-rouge: #E63946;
    --matisse-bleu: #1D3557;
    --matisse-vert: #2A9D8F;
    --matisse-jaune: #F4D03F;
    --matisse-rose: #D81B60;
    --matisse-orange: #E65100;
    --matisse-violet: #7209B7;
    
    /* Picasso */
    --picasso-rose-vif: #FF69B4;
    --picasso-vert-olive: #6B8E23;
    --picasso-jaune-ocre: #DAA520;
    --picasso-bleu-gris: #4682B4;
    --picasso-rouge-brique: #C1440E;
    
    /* Van Gogh */
    --vangogh-jaune-tournesol: #FFD700;
    --vangogh-bleu-iris: #4169E1;
    --vangogh-vert-cypres: #2F4F2F;
    --vangogh-orange-champ: #FF8C00;
    --vangogh-violet-nuit: #4B0082;
    
    /* Monet */
    --monet-bleu-nymphea: #89CFF0;
    --monet-vert-eau: #90EE90;
    --monet-rose-nenuphars: #FFB6C1;
    --monet-violet-glycine: #9370DB;
    --monet-jaune-soleil: #FFEF00;
    
    /* Chagall */
    --chagall-bleu-reveur: #4169E1;
    --chagall-rouge-amour: #DC143C;
    --chagall-vert-village: #3CB371;
    --chagall-jaune-lune: #FFD700;
    --chagall-violet-nocturn: #8B00FF;
    
    /* Accent Colors */
    --accent-green: #00BFA5;
    --accent-yellow: #FFC107;
    --accent-red: #E34F26;
    --accent-purple: #7B1FA2;
    
    /* Neutrals */
    --white: #FFFFFF;
    --light-gray: #F5F5F5;
    --medium-gray: #CCCCCC;
    --dark-gray: #333333;
    --text-primary: #2C3E50;
    --text-secondary: #7F8C8D;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 47, 167, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 47, 167, 0.15);
    --shadow-lg: 0 8px 32px rgba(0, 47, 167, 0.2);
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, var(--klein-blue) 0%, var(--klein-blue-light) 100%);
    --gradient-accent: linear-gradient(135deg, var(--accent-green) 0%, var(--accent-yellow) 100%);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--light-gray);
}

/* ==================
   HERO SECTION
   ================== */

.hero {
    background: var(--gradient-primary);
    color: var(--hero-text-color);
    padding: 80px 20px;
    text-align: center;
    box-shadow: var(--shadow-lg);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 1px, transparent 1px);
    background-size: 50px 50px;
    animation: moveBackground 20s linear infinite;
}

@keyframes moveBackground {
    0% { transform: translate(0, 0); }
    100% { transform: translate(50px, 50px); }
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 3em;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
    animation: fadeInDown 1s ease;
}

.tagline {
    font-size: 1.5em;
    margin-bottom: 10px;
    opacity: 0.95;
}

.subtitle {
    font-size: 1.1em;
    opacity: 0.85;
    letter-spacing: 2px;
}

/* ==================
   NAVIGATION
   ================== */

.main-nav {
    background: var(--white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    padding: 15px 20px;
    gap: 10px;
}

.nav-item {
    padding: 12px 24px;
    text-decoration: none;
    color: var(--text-primary);
    border-radius: 8px;
    transition: all 0.3s ease;
    font-weight: 500;
}

.nav-item:hover {
    background: var(--gradient-primary);
    color: var(--nav-text-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.nav-item.active {
    background: var(--klein-blue);
    color: var(--nav-text-hover);
}

/* ==================
   CONTAINER
   ================== */

.container {
    max-width: 1200px;
    margin: 40px auto;
    padding: 0 20px;
}

.section {
    background: var(--white);
    border-radius: 16px;
    padding: 40px;
    margin-bottom: 40px;
    box-shadow: var(--shadow-md);
    animation: fadeInUp 0.6s ease;
}

.section h2 {
    color: var(--klein-blue);
    font-size: 2em;
    margin-bottom: 30px;
    padding-bottom: 15px;
    border-bottom: 3px solid var(--klein-blue-light);
}

/* ==================
   DASHBOARD STATS
   ================== */

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.stat-card {
    background: var(--gradient-primary);
    color: var(--hero-text-color);
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-5px) scale(1.02);
}

.stat-icon {
    font-size: 3em;
    margin-bottom: 15px;
}

.stat-value {
    font-size: 2.5em;
    font-weight: bold;
    margin-bottom: 10px;
}

.stat-label {
    font-size: 0.9em;
    opacity: 0.9;
}

/* ==================
   LESSONS GRID
   ================== */

.lessons-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 25px;
    margin-top: 30px;
}

.lesson-card {
    background: linear-gradient(135deg, rgba(0, 47, 167, 0.05), rgba(0, 71, 255, 0.05));
    border: 2px solid var(--klein-blue-light);
    border-radius: 12px;
    padding: 25px;
    transition: all 0.3s ease;
}

.lesson-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--klein-blue);
}

.lesson-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.lesson-number {
    background: var(--klein-blue);
    color: var(--hero-text-color);
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.85em;
    font-weight: bold;
}

.lesson-level {
    font-size: 0.9em;
}

.lesson-card h3 {
    color: var(--klein-blue-dark);
    margin-bottom: 15px;
}

.lesson-card p {
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.lesson-meta {
    display: flex;
    gap: 15px;
    font-size: 0.9em;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

/* ==================
   CONVERSATION
   ================== */

.conversation-container {
    background: linear-gradient(135deg, rgba(0, 191, 165, 0.05), rgba(0, 47, 167, 0.05));
    border-radius: 12px;
    padding: 25px;
}

.conversation-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.conversation-header h3 {
    color: var(--klein-blue);
}

.difficulty-selector {
    padding: 10px 20px;
    border: 2px solid var(--klein-blue);
    border-radius: 8px;
    font-size: 1em;
    background: var(--white);
    color: var(--klein-blue);
    cursor: pointer;
    transition: all 0.3s ease;
}

.difficulty-selector:hover {
    background: var(--klein-blue);
    color: var(--white);
}

.chat-box {
    background: var(--white);
    border-radius: 12px;
    padding: 25px;
    height: 400px;
    overflow-y: auto;
    margin-bottom: 20px;
    border: 2px solid var(--medium-gray);
}

.ai-message, .user-message {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
    animation: slideIn 0.3s ease;
}

.user-message {
    flex-direction: row-reverse;
}

.message-avatar {
    font-size: 2em;
    flex-shrink: 0;
}

.message-content {
    background: linear-gradient(135deg, var(--klein-blue-light), var(--klein-blue));
    color: var(--hero-text-color);
    padding: 15px 20px;
    border-radius: 12px;
    max-width: 70%;
}

.user-message .message-content {
    background: linear-gradient(135deg, var(--accent-green), var(--accent-yellow));
}

.chat-input-container {
    display: flex;
    gap: 15px;
}

#chat-input {
    flex: 1;
    padding: 15px;
    border: 2px solid var(--klein-blue);
    border-radius: 8px;
    font-size: 1em;
    font-family: inherit;
    resize: vertical;
}

#chat-input:focus {
    outline: none;
    border-color: var(--klein-blue-light);
    box-shadow: 0 0 0 3px rgba(0, 47, 167, 0.1);
}

/* ==================
   READING SECTION
   ================== */

.reading-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 25px;
    margin-top: 30px;
}

.reading-card {
    background: linear-gradient(135deg, rgba(0, 47, 167, 0.05), rgba(255, 255, 255, 1));
    border-left: 5px solid var(--klein-blue);
    border-radius: 12px;
    padding: 25px;
    transition: all 0.3s ease;
}

.reading-card:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow-lg);
}

.reading-level {
    display: inline-block;
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.85em;
    font-weight: bold;
    margin-bottom: 15px;
    background: var(--klein-blue);
    color: var(--hero-text-color);
}

/* ==================
   VOCABULARY
   ================== */

.vocabulary-container {
    margin-top: 30px;
}

.vocabulary-search {
    display: flex;
    gap: 15px;
    margin-bottom: 25px;
}

#vocab-search {
    flex: 1;
    padding: 15px;
    border: 2px solid var(--klein-blue);
    border-radius: 8px;
    font-size: 1em;
}

.vocabulary-themes {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 30px;
}

.theme-btn {
    padding: 12px 24px;
    background: var(--white);
    border: 2px solid var(--klein-blue);
    color: var(--klein-blue);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
}

.theme-btn:hover {
    background: var(--klein-blue);
    color: var(--white);
}

/* ==================
   GRAMMAR SECTION
   ================== */

.grammar-topics {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 25px;
    margin-top: 30px;
}

.grammar-card {
    background: linear-gradient(135deg, rgba(0, 47, 167, 0.05), rgba(0, 71, 255, 0.05));
    border: 2px solid var(--klein-blue-light);
    border-radius: 12px;
    padding: 25px;
}

.grammar-card h3 {
    color: var(--klein-blue);
    margin-bottom: 15px;
}

.grammar-card ul {
    list-style: none;
    margin-bottom: 20px;
}

.grammar-card li {
    padding: 8px 0;
    border-bottom: 1px solid var(--medium-gray);
}

.grammar-card li:before {
    content: "✓ ";
    color: var(--accent-green);
    font-weight: bold;
}

/* ==================
   EXERCISES
   ================== */

.exercises-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
    margin-top: 30px;
}

.exercise-card {
    background: var(--white);
    border: 2px solid var(--klein-blue-light);
    border-radius: 12px;
    padding: 30px;
    text-align: center;
    transition: all 0.3s ease;
}

.exercise-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.exercise-type {
    background: var(--gradient-primary);
    color: var(--hero-text-color);
    padding: 10px 20px;
    border-radius: 8px;
    display: inline-block;
    margin-bottom: 15px;
    font-weight: bold;
}

/* ==================
   BUTTONS
   ================== */

.btn-primary {
    background: var(--gradient-primary);
    color: var(--hero-text-color);
    padding: 14px 28px;
    border: none;
    border-radius: 8px;
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

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

.btn-secondary {
    background: var(--white);
    color: var(--klein-blue);
    padding: 12px 24px;
    border: 2px solid var(--klein-blue);
    border-radius: 8px;
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-secondary:hover {
    background: var(--klein-blue);
    color: var(--white);
}

.btn-send {
    background: var(--gradient-accent);
    color: var(--dark-gray);
    padding: 15px 30px;
    border: none;
    border-radius: 8px;
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

.btn-send:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-md);
}

/* ==================
   FOOTER
   ================== */

.footer {
    background: var(--gradient-primary);
    color: var(--hero-text-color);
    text-align: center;
    padding: 40px 20px;
    margin-top: 60px;
}

.footer p {
    margin: 10px 0;
    opacity: 0.9;
}

/* ==================
   ANIMATIONS
   ================== */

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

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

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* ==================
   RESPONSIVE DESIGN
   ================== */

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2em;
    }
    
    .tagline {
        font-size: 1.2em;
    }
    
    .nav-container {
        flex-direction: column;
    }
    
    .section {
        padding: 25px;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .lessons-grid,
    .reading-grid,
    .grammar-topics,
    .exercises-container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .conversation-header {
        flex-direction: column;
        gap: 15px;
    }
    
    .chat-input-container {
        flex-direction: column;
    }
}

/* ==================
   TOP BAR & USER MANAGEMENT
   ================== */

.top-bar {
    background: var(--white);
    box-shadow: var(--shadow-sm);
    padding: 12px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 99;
}

.current-user-info {
    display: flex;
    align-items: center;
    gap: 10px;
}

.user-icon {
    font-size: 1.5em;
}

.user-name {
    font-weight: bold;
    color: var(--klein-blue);
    font-size: 1.1em;
}

.btn-switch-user,
.btn-reset {
    background: var(--light-gray);
    border: 2px solid var(--klein-blue);
    color: var(--klein-blue);
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.9em;
}

.btn-switch-user:hover,
.btn-reset:hover {
    background: var(--klein-blue);
    color: var(--white);
}

.btn-painter {
    background: var(--gradient-primary);
    color: var(--hero-text-color);
    border: none;
    padding: 8px 20px;
    border-radius: 999px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95em;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

.btn-painter:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-md);
}

/* User Panel (Modal) */
.user-panel {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    z-index: 1000;
    justify-content: center;
    align-items: center;
}

.user-panel.show {
    display: flex;
}

.user-panel-content {
    background: var(--white);
    border-radius: 20px;
    padding: 40px;
    max-width: 500px;
    width: 90%;
    box-shadow: var(--shadow-lg);
    animation: slideIn 0.3s ease;
}

.user-panel-content h2 {
    color: var(--klein-blue);
    margin-bottom: 25px;
    text-align: center;
}

.user-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 15px;
    margin-bottom: 25px;
}

.user-btn {
    background: var(--gradient-primary);
    color: var(--hero-text-color);
    border: none;
    padding: 20px;
    border-radius: 12px;
    cursor: pointer;
    font-size: 1em;
    font-weight: 600;
    transition: all 0.3s ease;
    position: relative;
}

.user-btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.user-btn .delete-user {
    position: absolute;
    top: 5px;
    right: 5px;
    background: var(--accent-red);
    color: var(--white);
    border: none;
    border-radius: 50%;
    width: 24px;
    height: 24px;
    font-size: 0.8em;
    cursor: pointer;
    display: none;
}

.user-btn:hover .delete-user {
    display: block;
}

.btn-add-user {
    background: var(--accent-green);
    color: var(--white);
    border: 2px dashed var(--white);
    padding: 15px;
    border-radius: 12px;
    cursor: pointer;
    font-size: 1em;
    font-weight: 600;
    transition: all 0.3s ease;
    width: 100%;
}

.btn-add-user:hover {
    background: var(--accent-yellow);
    color: var(--dark-gray);
}