/* ===== CSS VARIABLES - BRAND COLORS ===== */
:root {
    /* Primary Color Palette */
    --primary-blue-light: #1565C0;
    --primary-blue-dark: #90CAF9;
    --secondary-blue: #1976D2;
    --accent-blue: #2196F3;
    
    /* Supporting Colors */
    --success-green: #4CAF50;
    --feature-green: #388E3C;
    --warning-orange: #FF9800;
    --error-red: #D32F2F;
    --profile-blue: #3B82F6;
    
    /* Neutral Palette */
    --pure-white: #FFFFFF;
    --light-gray: #F5F5F5;
    --selected-light-blue: #BBDDEF;
    --dark-background: #121212;
    --deep-navy: #0D1117;
    
    /* Additional Colors */
    --text-dark: #333333;
    --text-medium: #666666;
    --hero-bg: linear-gradient(135deg, #F8FBFF 0%, #E3F2FD 100%);
    --benefits-bg: #F8FBFF;
    
    /* Spacing */
    --section-padding: 80px 0;
    --container-padding: 0 20px;
    --card-padding: 30px;
    
    /* Typography */
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --h1-size: 3.5rem;
    --h2-size: 2.5rem;
    --h3-size: 1.8rem;
    --body-size: 1.1rem;
    --small-size: 0.9rem;
    
    /* Shadows */
    --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --button-shadow: 0 2px 4px rgba(21, 101, 192, 0.3);
    --hero-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

/* ===== GLOBAL STYLES ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--pure-white);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--container-padding);
}

.section-title {
    font-size: var(--h2-size);
    color: var(--primary-blue-light);
    text-align: center;
    margin-bottom: 50px;
    font-weight: 700;
}

/* ===== BUTTONS ===== */
.btn {
    display: inline-block;
    padding: 15px 30px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: var(--body-size);
    transition: all 0.3s ease;
    border: 2px solid;
    cursor: pointer;
    text-align: center;
}

.btn-primary {
    background-color: var(--primary-blue-light);
    color: var(--pure-white);
    border-color: var(--primary-blue-light);
    box-shadow: var(--button-shadow);
}

.btn-primary:hover {
    background-color: #1976D2;
    border-color: #1976D2;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(21, 101, 192, 0.4);
}

.btn-secondary {
    background-color: var(--pure-white);
    color: var(--primary-blue-light);
    border-color: var(--primary-blue-light);
}

.btn-secondary:hover {
    background-color: var(--primary-blue-light);
    color: var(--pure-white);
    transform: translateY(-2px);
}

.btn-large {
    padding: 18px 40px;
    font-size: 1.2rem;
}

/* ===== NAVIGATION ===== */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: var(--pure-white);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
    gap: 2rem;
}

.nav-container > .nav-menu {
    flex-grow: 1;
    justify-content: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.nav-logo img {
    height: 40px;
    width: auto;
}

.nav-logo h2 {
    color: var(--primary-blue-light);
    font-size: 1.8rem;
    font-weight: 700;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-link {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: var(--primary-blue-light);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    padding: 5px;
    z-index: 1001;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: var(--primary-blue-light);
    margin: 3px 0;
    transition: 0.3s;
    border-radius: 2px;
}

/* ===== HERO SECTION ===== */
.hero {
    background: var(--hero-bg);
    padding: 150px 0 80px;
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--container-padding);
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-content {
    animation: fadeInLeft 0.8s ease-out;
}

.hero-title {
    font-size: var(--h1-size);
    color: var(--primary-blue-light);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 20px;
}

.hero-subtitle {
    font-size: 1.3rem;
    color: var(--text-medium);
    margin-bottom: 40px;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    margin-bottom: 30px;
}

.trust-indicators {
    display: flex;
    align-items: center;
    gap: 15px;
    color: var(--text-medium);
    font-size: var(--small-size);
    font-weight: 500;
}

/* ===== APP MOCKUP ===== */
.hero-image {
    display: flex;
    justify-content: center;
    animation: fadeInRight 0.8s ease-out;
}

.phone-frame {
    width: 280px;
    height: 560px;
    background: linear-gradient(145deg, #e6e6e6, #ffffff);
    border-radius: 30px;
    padding: 20px;
    box-shadow: var(--hero-shadow);
    position: relative;
}

.screen {
    width: 100%;
    height: 100%;
    background-color: var(--pure-white);
    border-radius: 25px;
    overflow: hidden;
    box-shadow: inset 0 0 20px rgba(0, 0, 0, 0.1);
}

.app-interface {
    padding: 20px;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.grade-selector {
    background-color: var(--primary-blue-light);
    color: var(--pure-white);
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.9rem;
}

.profile-icon {
    width: 35px;
    height: 35px;
    background-color: var(--profile-blue);
    border-radius: 50%;
}

.subject-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    flex-grow: 1;
}

.subject-card {
    background-color: var(--light-gray);
    border-radius: 15px;
    padding: 20px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}

.subject-card:hover {
    background-color: var(--selected-light-blue);
    transform: translateY(-2px);
}

.subject-icon {
    font-size: 2rem;
    margin-bottom: 10px;
}

/* Removed AI tutor button styles - no longer needed
.ai-tutor-button {
    background-color: var(--success-green);
    color: var(--pure-white);
    padding: 15px;
    border-radius: 15px;
    text-align: center;
    font-weight: 600;
    margin-top: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.ai-tutor-button:hover {
    background-color: var(--feature-green);
    transform: translateY(-2px);
}
*/

/* ===== BENEFITS SECTION ===== */
.benefits {
    background-color: var(--benefits-bg);
    padding: var(--section-padding);
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 40px;
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--container-padding);
}

.benefit-card {
    background-color: var(--pure-white);
    padding: var(--card-padding);
    border-radius: 15px;
    box-shadow: var(--card-shadow);
    text-align: center;
    transition: transform 0.3s ease;
}

.benefit-card:hover {
    transform: translateY(-5px);
}

.benefit-icon {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    font-size: 2rem;
}

.benefit-icon.learn {
    background-color: rgba(76, 175, 80, 0.1);
    color: var(--success-green);
}

.benefit-icon.focus {
    background-color: rgba(21, 101, 192, 0.1);
    color: var(--primary-blue-light);
}

.benefit-icon.progress {
    background-color: rgba(59, 130, 246, 0.1);
    color: var(--profile-blue);
}

.benefit-card h3 {
    font-size: var(--h3-size);
    color: var(--primary-blue-light);
    margin-bottom: 20px;
    font-weight: 600;
}

.benefit-card ul {
    list-style: none;
    text-align: left;
}

.benefit-card li {
    margin-bottom: 12px;
    position: relative;
    padding-left: 25px;
    color: var(--text-dark);
}

.benefit-card li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success-green);
    font-weight: bold;
}

/* ===== SOCIAL PROOF SECTION ===== */
.social-proof {
    padding: var(--section-padding);
    background-color: var(--pure-white);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 60px;
}

.testimonial-card {
    background-color: var(--light-gray);
    padding: var(--card-padding);
    border-radius: 15px;
    box-shadow: var(--card-shadow);
    transition: transform 0.3s ease;
}

.testimonial-card:hover {
    transform: translateY(-3px);
    background-color: var(--selected-light-blue);
}

.testimonial-content {
    margin-bottom: 20px;
}

.testimonial-content p {
    font-style: italic;
    color: var(--text-dark);
    font-size: var(--body-size);
    line-height: 1.6;
}

.testimonial-author {
    display: flex;
    align-items: center;
    gap: 15px;
}

.author-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--primary-blue-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.author-name {
    font-weight: 600;
    color: var(--primary-blue-light);
    display: block;
}

.author-grade {
    color: var(--text-medium);
    font-size: var(--small-size);
}

.stats-section {
    display: flex;
    justify-content: center;
    gap: 80px;
    margin-top: 60px;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-blue-light);
    margin-bottom: 10px;
}

.stat-label {
    color: var(--text-medium);
    font-size: var(--body-size);
    font-weight: 500;
}

/* ===== CTA SECTION ===== */
.cta-section {
    background: linear-gradient(135deg, var(--primary-blue-light) 0%, var(--secondary-blue) 100%);
    padding: var(--section-padding);
    color: var(--pure-white);
    text-align: center;
}

.cta-content h2 {
    font-size: var(--h2-size);
    margin-bottom: 20px;
    font-weight: 700;
}

.cta-content p {
    font-size: 1.2rem;
    margin-bottom: 40px;
    opacity: 0.9;
}

.cta-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
}

.cta-section .btn-primary {
    background-color: var(--pure-white);
    color: var(--primary-blue-light);
    border-color: var(--pure-white);
}

.cta-section .btn-primary:hover {
    background-color: var(--light-gray);
    border-color: var(--light-gray);
}

.cta-section .btn-secondary {
    background-color: transparent;
    color: var(--pure-white);
    border-color: var(--pure-white);
}

.cta-section .btn-secondary:hover {
    background-color: var(--pure-white);
    color: var(--primary-blue-light);
}

/* ===== FOOTER ===== */
.footer {
    background-color: var(--dark-background);
    color: var(--pure-white);
    padding: 60px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    color: var(--primary-blue-dark);
    font-size: 1.5rem;
    margin-bottom: 20px;
    font-weight: 700;
}

.footer-section h4 {
    color: var(--pure-white);
    font-size: 1.1rem;
    margin-bottom: 15px;
    font-weight: 600;
}

.footer-section p {
    color: #CCCCCC;
    line-height: 1.6;
    margin-bottom: 20px;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 8px;
}

.footer-section ul li a {
    color: #CCCCCC;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section ul li a:hover {
    color: var(--primary-blue-dark);
}

.social-links {
    display: flex;
    gap: 15px;
}

.social-link {
    width: 40px;
    height: 40px;
    background-color: var(--primary-blue-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    font-size: 1.2rem;
    transition: all 0.3s ease;
}

.social-link:hover {
    background-color: var(--primary-blue-dark);
    transform: translateY(-2px);
}

.footer-bottom {
    border-top: 1px solid #333;
    padding-top: 20px;
    text-align: center;
    color: #999;
}

/* ===== ANIMATIONS ===== */
@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);
    }
}

/* ===== UTILITY ANIMATIONS ===== */
@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes slideOut {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}

@keyframes slideOutRight {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}

/* Error toast styles */
.error-toast {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: 14px;
    font-weight: 500;
    max-width: 300px;
    word-wrap: break-word;
    cursor: pointer;
    transition: transform 0.2s ease;
}

.error-toast:hover {
    transform: scale(1.02);
}

/* ===== VIDEO MODAL ===== */
.video-modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    animation: fadeIn 0.3s ease;
}

/* Web Version - Desktop and Tablets */
.video-modal-content {
    position: relative;
    margin: 8% auto;
    width: 480px;
    max-width: 70vw;
    max-height: 60vh;
    background: transparent;
    animation: slideIn 0.3s ease;
}

.video-modal-close {
    position: absolute;
    right: -50px;
    top: -50px;
    color: var(--pure-white);
    font-size: 32px;
    font-weight: bold;
    cursor: pointer;
    z-index: 1001;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background-color: rgba(0, 0, 0, 0.6);
    transition: all 0.3s ease;
}

.video-modal-close:hover {
    background-color: rgba(0, 0, 0, 0.9);
    transform: scale(1.1);
}

.video-modal video {
    width: 100%;
    height: auto;
    max-height: 60vh;
    border-radius: 12px;
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.6);
    object-fit: contain;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideIn {
    from { 
        opacity: 0;
        transform: translateY(-50px);
    }
    to { 
        opacity: 1;
        transform: translateY(0);
    }
}


/* ===== RESPONSIVE DESIGN ===== */
@media screen and (max-width: 768px) {
    :root {
        --h1-size: 2.5rem;
        --h2-size: 2rem;
        --h3-size: 1.5rem;
        --section-padding: 60px 0;
    }
    
    .nav-logo img {
        height: 32px;
    }
    
    .nav-logo h2 {
        font-size: 1.5rem;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--pure-white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 20px 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero {
        padding: 120px 0 60px;
        min-height: auto;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .phone-frame {
        width: 250px;
        height: 500px;
    }
    
    .benefits-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .stats-section {
        flex-direction: column;
        gap: 30px;
    }
    
    .cta-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
        text-align: center;
    }
    
    /* Tablet Version */
    .video-modal-content {
        margin: 10% auto;
        width: 85%;
        max-width: 700px;
    }
    
    .video-modal-close {
        right: -30px;
        top: -30px;
        font-size: 28px;
        width: 35px;
        height: 35px;
    }
}

@media screen and (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .btn {
        padding: 12px 24px;
        font-size: 1rem;
    }
    
    .btn-large {
        padding: 15px 30px;
        font-size: 1.1rem;
    }
    
    .benefit-card {
        padding: 20px;
    }
    
    .testimonial-card {
        padding: 20px;
    }
    
    /* Mobile Version */
    .video-modal-content {
        margin: 15% auto;
        width: 95%;
        max-width: none;
    }
    
    .video-modal-close {
        right: -15px;
        top: -15px;
        font-size: 24px;
        width: 30px;
        height: 30px;
    }
    
    .video-modal video {
        border-radius: 8px;
        box-shadow: 0 8px 25px rgba(0, 0, 0, 0.4);
    }
}

/* Extra Small Mobile Version */
@media screen and (max-width: 360px) {
    .video-modal-content {
        margin: 10% auto;
        width: 98%;
    }
    
    .video-modal-close {
        right: -10px;
        top: -10px;
        font-size: 20px;
        width: 25px;
        height: 25px;
    }
    
    .video-modal video {
        border-radius: 6px;
    }
}

/* ===== UTILITY CLASSES ===== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-1 { margin-bottom: 10px; }
.mb-2 { margin-bottom: 20px; }
.mb-3 { margin-bottom: 30px; }
.mb-4 { margin-bottom: 40px; }

.mt-1 { margin-top: 10px; }
.mt-2 { margin-top: 20px; }
.mt-3 { margin-top: 30px; }
.mt-4 { margin-top: 40px; }

.p-1 { padding: 10px; }
.p-2 { padding: 20px; }
.p-3 { padding: 30px; }
.p-4 { padding: 40px; }

.color-primary { color: var(--primary-blue-light); }
.color-success { color: var(--success-green); }
.color-warning { color: var(--warning-orange); }
.color-error { color: var(--error-red); }