/* ERNIE 5.0 Landing Page - Purple Theme */

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

:root {
    --primary-purple: #7C3AED;
    --primary-dark: #6D28D9;
    --primary-light: #8B5CF6;
    --secondary-purple: #A78BFA;
    --accent-purple: #C4B5FD;
    --deep-purple: #5B21B6;
    --text-dark: #1F2937;
    --text-gray: #4B5563;
    --text-light: #6B7280;
    --bg-white: #FFFFFF;
    --bg-light: #F9FAFB;
    --bg-purple-light: #FAF5FF;
    --border-color: #E5E7EB;
    --gradient-1: linear-gradient(135deg, #7C3AED 0%, #A78BFA 100%);
    --gradient-2: linear-gradient(135deg, #5B21B6 0%, #7C3AED 100%);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-white);
    font-size: 16px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

section {
    padding: 70px 0;
}

h1, h2, h3, h4, h5, h6 {
    line-height: 1.3;
    font-weight: 700;
}

h1 { font-size: 48px; }
h2 { font-size: 40px; }
h3 { font-size: 24px; }

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

ul {
    list-style: none;
}

/* Button Styles */
.btn-primary, .btn-primary-large {
    background: var(--primary-purple);
    color: var(--bg-white);
    padding: 14px 32px;
    border-radius: 8px;
    font-weight: 600;
    display: inline-block;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-primary-large {
    padding: 16px 40px;
    font-size: 18px;
}

.btn-primary:hover, .btn-primary-large:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.btn-outline, .btn-outline-large {
    background: transparent;
    color: var(--primary-purple);
    padding: 14px 32px;
    border-radius: 8px;
    font-weight: 600;
    display: inline-block;
    border: 2px solid var(--primary-purple);
    transition: all 0.3s ease;
}

.btn-outline-large {
    padding: 16px 40px;
    font-size: 18px;
}

.btn-outline:hover, .btn-outline-large:hover {
    background: var(--primary-purple);
    color: var(--bg-white);
    transform: translateY(-2px);
}

/* Navigation Header */
.header {
    background: var(--bg-white);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: box-shadow 0.3s ease;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    max-width: 1200px;
    margin: 0 auto;
}

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

.nav-brand .logo {
    font-size: 28px;
    font-weight: 800;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.preview-badge {
    background: var(--accent-purple);
    color: var(--deep-purple);
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.nav-menu {
    display: flex;
    gap: 36px;
}

.nav-menu a {
    color: var(--text-gray);
    font-weight: 500;
    font-size: 15px;
    position: relative;
}

.nav-menu a:hover {
    color: var(--primary-purple);
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-purple);
    transition: width 0.3s ease;
}

.nav-menu a:hover::after {
    width: 100%;
}

.hamburger {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    gap: 5px;
}

.hamburger span {
    width: 28px;
    height: 3px;
    background: var(--primary-purple);
    border-radius: 2px;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    background: var(--gradient-2);
    padding: 100px 0 80px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(167, 139, 250, 0.3) 0%, transparent 70%);
    border-radius: 50%;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    position: relative;
    z-index: 1;
}

.hero-badge {
    display: inline-block;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    padding: 10px 24px;
    border-radius: 24px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    font-size: 14px;
    font-weight: 600;
    color: var(--bg-white);
    margin-bottom: 24px;
}

.hero-title {
    color: var(--bg-white);
    margin-bottom: 24px;
    font-size: 56px;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 20px;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 36px;
    line-height: 1.6;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
}

.hero .btn-primary-large {
    background: var(--bg-white);
    color: var(--primary-purple);
}

.hero .btn-primary-large:hover {
    background: var(--bg-light);
}

.hero .btn-outline-large {
    color: var(--bg-white);
    border-color: var(--bg-white);
}

.hero .btn-outline-large:hover {
    background: rgba(255, 255, 255, 0.1);
}

/* Section Header */
.section-header {
    text-align: center;
    margin-bottom: 56px;
}

.section-header h2 {
    margin-bottom: 16px;
    color: var(--text-dark);
}

.section-header p {
    font-size: 18px;
    color: var(--text-gray);
    max-width: 600px;
    margin: 0 auto;
}

/* About Section */
.about {
    background: var(--bg-white);
}

.about-content {
    max-width: 900px;
    margin: 0 auto;
}

.about-text {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.about-text p {
    font-size: 18px;
    line-height: 1.8;
    color: var(--text-gray);
}

/* Features Section */
.features {
    background: var(--bg-purple-light);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.feature-card {
    background: var(--bg-white);
    padding: 36px 28px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 24px rgba(124, 58, 237, 0.15);
    border-color: var(--secondary-purple);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 20px;
}

.feature-card h3 {
    margin-bottom: 16px;
    color: var(--text-dark);
}

.feature-card p {
    color: var(--text-gray);
    line-height: 1.7;
}

/* Capabilities Section */
.capabilities {
    background: var(--bg-white);
}

.capabilities-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.capability-card {
    background: var(--bg-light);
    padding: 36px 32px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.capability-card:hover {
    border-color: var(--primary-purple);
    background: var(--bg-white);
    box-shadow: 0 8px 16px rgba(124, 58, 237, 0.1);
}

.capability-card h3 {
    color: var(--primary-purple);
    margin-bottom: 16px;
    font-size: 22px;
}

.capability-card > p {
    color: var(--text-gray);
    margin-bottom: 20px;
    line-height: 1.7;
}

.capability-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.capability-list li {
    color: var(--text-gray);
    padding-left: 28px;
    position: relative;
    line-height: 1.6;
}

.capability-list li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-purple);
    font-weight: 700;
    font-size: 18px;
}

/* Applications Section */
.applications {
    background: var(--bg-purple-light);
}

.applications-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.application-card {
    background: var(--bg-white);
    padding: 32px 28px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.application-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 10px 20px rgba(124, 58, 237, 0.12);
}

.application-icon {
    font-size: 40px;
    margin-bottom: 16px;
}

.application-card h3 {
    font-size: 20px;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.application-card p {
    color: var(--text-gray);
    line-height: 1.7;
}

/* Contact Section */
.contact {
    background: var(--gradient-1);
    padding: 80px 0;
}

.contact-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.contact-content h2 {
    color: var(--bg-white);
    margin-bottom: 16px;
}

.contact-content > p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 18px;
    margin-bottom: 36px;
    line-height: 1.7;
}

.newsletter-form {
    display: flex;
    gap: 12px;
    margin-bottom: 28px;
    justify-content: center;
}

.newsletter-form input[type="email"] {
    flex: 1;
    max-width: 400px;
    padding: 16px 20px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 8px;
    font-size: 16px;
    background: rgba(255, 255, 255, 0.1);
    color: var(--bg-white);
    backdrop-filter: blur(10px);
}

.newsletter-form input[type="email"]::placeholder {
    color: rgba(255, 255, 255, 0.6);
}

.newsletter-form input[type="email"]:focus {
    outline: none;
    border-color: var(--bg-white);
    background: rgba(255, 255, 255, 0.15);
}

.newsletter-form .btn-primary {
    background: var(--bg-white);
    color: var(--primary-purple);
    white-space: nowrap;
}

.newsletter-form .btn-primary:hover {
    background: var(--bg-light);
}

.contact-info {
    color: rgba(255, 255, 255, 0.85);
    font-size: 15px;
}

.contact-info a {
    color: var(--bg-white);
    text-decoration: underline;
}

.contact-info a:hover {
    color: var(--accent-purple);
}

/* Footer */
.footer {
    background: var(--text-dark);
    color: var(--bg-white);
    padding: 56px 0 32px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 48px;
    margin-bottom: 36px;
}

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 20px;
    color: var(--bg-white);
}

.footer-section p {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.7;
    font-size: 15px;
}

.footer-section ul {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.7);
    font-size: 15px;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: var(--secondary-purple);
}

.footer-bottom {
    padding-top: 28px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
}

.footer-bottom p {
    color: rgba(255, 255, 255, 0.6);
    font-size: 14px;
    margin-bottom: 8px;
}

.footer-note {
    font-size: 13px !important;
    color: rgba(255, 255, 255, 0.5) !important;
}

/* Responsive Design */

/* Tablets and below (max-width: 992px) */
@media (max-width: 992px) {
    h1 { font-size: 42px; }
    h2 { font-size: 36px; }
    h3 { font-size: 22px; }
    
    section {
        padding: 56px 0;
    }
    
    .hero {
        padding: 80px 0 60px;
    }
    
    .hero-title {
        font-size: 48px;
    }
    
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 28px;
    }
    
    .capabilities-grid {
        grid-template-columns: 1fr;
        gap: 28px;
    }
    
    .applications-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }
    
    .footer-content {
        grid-template-columns: 1fr 1fr;
        gap: 36px;
    }
}

/* Mobile devices (max-width: 768px) */
@media (max-width: 768px) {
    h1 { font-size: 36px; }
    h2 { font-size: 32px; }
    h3 { font-size: 20px; }
    
    .container {
        padding: 0 20px;
    }
    
    section {
        padding: 48px 0;
    }
    
    /* Navigation */
    .navbar {
        padding: 16px 20px;
    }
    
    .nav-brand .logo {
        font-size: 24px;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 73px;
        flex-direction: column;
        background: var(--bg-white);
        width: 100%;
        text-align: left;
        transition: 0.3s;
        padding: 28px 24px;
        border-top: 1px solid var(--border-color);
        gap: 24px;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-menu a::after {
        display: none;
    }
    
    .hamburger {
        display: flex;
    }
    
    /* Hero */
    .hero {
        padding: 60px 0 48px;
    }
    
    .hero-title {
        font-size: 36px;
    }
    
    .hero-subtitle {
        font-size: 18px;
        margin-bottom: 28px;
    }
    
    .hero-actions {
        flex-direction: column;
        gap: 12px;
    }
    
    .hero-actions a {
        width: 100%;
        text-align: center;
    }
    
    /* About */
    .about-text p {
        font-size: 16px;
    }
    
    /* Features */
    .section-header {
        margin-bottom: 40px;
    }
    
    .section-header h2 {
        font-size: 32px;
    }
    
    .section-header p {
        font-size: 16px;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    
    .feature-card {
        padding: 28px 24px;
    }
    
    /* Capabilities */
    .capability-card {
        padding: 28px 24px;
    }
    
    /* Applications */
    .applications-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .application-card {
        padding: 28px 24px;
    }
    
    /* Contact */
    .contact {
        padding: 60px 0;
    }
    
    .newsletter-form {
        flex-direction: column;
        gap: 12px;
    }
    
    .newsletter-form input[type="email"] {
        max-width: 100%;
    }
    
    /* Footer */
    .footer {
        padding: 48px 0 28px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }
}

/* Small mobile devices (max-width: 480px) */
@media (max-width: 480px) {
    h1 { font-size: 32px; }
    h2 { font-size: 28px; }
    
    .hero-title {
        font-size: 32px;
    }
    
    .btn-primary-large, .btn-outline-large {
        padding: 14px 32px;
        font-size: 16px;
    }
}