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

:root {
    /* Primary Colors */
    --primary-color: #007AFF;
    --primary-dark: #0051D0;
    --primary-light: #5AC8FA;
    
    /* Background Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    
    /* Text Colors */
    --text-primary: #1d1d1f;
    --text-secondary: #86868b;
    --text-tertiary: #6e6e73;
    
    /* Accent Colors */
    --accent-green: #30d158;
    --accent-red: #ff3b30;
    --accent-orange: #ff9500;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.15);
    --shadow-xl: 0 20px 40px rgba(0,0,0,0.1);
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
}

/* Dark Theme */
[data-theme="dark"] {
    --bg-primary: #000000;
    --bg-secondary: #1c1c1e;
    --bg-tertiary: #2c2c2e;
    --text-primary: #ffffff;
    --text-secondary: #98989d;
    --text-tertiary: #8e8e93;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

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

/* ===== Navigation ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    z-index: 1000;
    transition: all 0.3s ease;
}

[data-theme="dark"] .navbar {
    background: rgba(0, 0, 0, 0.95);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-logo i {
    margin-right: var(--spacing-xs);
    font-size: 1.5rem;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

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

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

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

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

.language-switch {
    margin-left: var(--spacing-md);
}

.lang-btn {
    background: none;
    border: 1px solid var(--bg-tertiary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-sm);
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.lang-btn:hover {
    background: var(--bg-secondary);
    border-color: var(--primary-color);
}

/* ===== Hero Section ===== */
.hero {
    padding-top: 120px;
    padding-bottom: var(--spacing-2xl);
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
}

.hero-text h1 {
    font-size: var(--font-size-5xl);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
}

.hero-text p {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.6;
}

.download-buttons {
    display: flex;
    gap: var(--spacing-md);
}

.app-store-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background: var(--text-primary);
    color: white;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    text-decoration: none;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-md);
}

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

.app-store-btn i {
    font-size: 1.5rem;
}

.app-store-btn div {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.app-store-btn small {
    font-size: var(--font-size-xs);
    opacity: 0.8;
}

/* App Screenshots Styles */
.app-screenshots {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-lg);
    height: 500px;
    justify-content: center;
}

.screenshot-container {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.phone-frame {
    position: relative;
    width: 280px;
    height: 400px;
    background: linear-gradient(145deg, #f0f0f0, #ffffff);
    border-radius: 30px;
    padding: 12px;
    box-shadow: 
        0 8px 32px rgba(0,0,0,0.12),
        inset 0 1px 0 rgba(255,255,255,0.8),
        inset 0 -1px 0 rgba(0,0,0,0.1);
    overflow: hidden;
}

.phone-frame::before {
    content: '';
    position: absolute;
    top: 8px;
    left: 50%;
    transform: translateX(-50%);
    width: 120px;
    height: 6px;
    background: #333;
    border-radius: 3px;
    z-index: 10;
}

.screenshot-img {
    position: absolute;
    top: 20px;
    left: 12px;
    width: calc(100% - 24px);
    height: calc(100% - 40px);
    border-radius: 22px;
    object-fit: cover;
    opacity: 0;
    transition: all 0.5s ease;
    transform: scale(0.95);
}

.screenshot-img.active {
    opacity: 1;
    transform: scale(1);
}

.screenshot-img.fallback {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: var(--font-size-lg);
    font-weight: 500;
}

.screenshot-dots {
    display: flex;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-md);
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(0, 122, 255, 0.3);
    cursor: pointer;
    transition: all 0.3s ease;
}

.dot.active,
.dot:hover {
    background: var(--primary-color);
    transform: scale(1.2);
}

.screenshot-description {
    text-align: center;
    max-width: 300px;
}

.screenshot-text {
    font-size: var(--font-size-base);
    color: var(--text-secondary);
    margin: 0;
    opacity: 0;
    transition: all 0.5s ease;
    transform: translateY(10px);
}

.screenshot-text.active {
    opacity: 1;
    transform: translateY(0);
}

/* Loading placeholder for missing images */
.screenshot-img[src="screenshots/screenshot-1.png"]:not([data-loaded]),
.screenshot-img[src="screenshots/screenshot-2.png"]:not([data-loaded]),
.screenshot-img[src="screenshots/screenshot-3.png"]:not([data-loaded]) {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: var(--font-size-lg);
    font-weight: 500;
}

.screenshot-img[src="screenshots/screenshot-1.png"]:not([data-loaded])::before {
    content: '主界面';
}

.screenshot-img[src="screenshots/screenshot-2.png"]:not([data-loaded])::before {
    content: 'AI语音';
}

.screenshot-img[src="screenshots/screenshot-3.png"]:not([data-loaded])::before {
    content: '事件列表';
}

/* ===== Features Section ===== */
.features {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-primary);
}

.features h2 {
    text-align: center;
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--spacing-2xl);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
}

.feature-card {
    background: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid var(--bg-tertiary);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--spacing-md);
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: white;
}

.feature-card h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ===== FAQ Section ===== */
.faq {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-secondary);
}

.faq h2 {
    text-align: center;
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--spacing-2xl);
}

.faq-container {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--bg-primary);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
    overflow: hidden;
    border: 1px solid var(--bg-tertiary);
    transition: all 0.3s ease;
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
}

.faq-question {
    padding: var(--spacing-lg);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
}

.faq-question:hover {
    background: var(--bg-secondary);
}

.faq-question h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
}

.faq-question i {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    transition: transform 0.3s ease;
}

.faq-item.active .faq-question i {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
    background: var(--bg-secondary);
}

.faq-item.active .faq-answer {
    max-height: 200px;
}

.faq-answer p {
    padding: var(--spacing-lg);
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ===== Contact Section ===== */
.contact {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-primary);
}

.contact h2 {
    text-align: center;
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--spacing-2xl);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: start;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.contact-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    transition: all 0.3s ease;
}

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

.contact-item i {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.contact-item h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.contact-item p {
    color: var(--text-secondary);
}

.contact-form {
    background: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    border: 1px solid var(--bg-tertiary);
}

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

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-sm);
    border: 1px solid var(--bg-tertiary);
    border-radius: var(--radius-sm);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: inherit;
    font-size: var(--font-size-base);
    transition: all 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
}

.submit-btn {
    width: 100%;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    color: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.submit-btn:active {
    transform: translateY(0);
}

/* ===== Footer ===== */
.footer {
    background: var(--text-primary);
    color: white;
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: var(--spacing-md);
    font-weight: 600;
}

.footer-section p,
.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    margin-bottom: var(--spacing-xs);
    display: block;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: var(--primary-light);
}

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

.footer-bottom p {
    color: rgba(255, 255, 255, 0.6);
    margin: 0;
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
    .hero-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
        text-align: center;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }
    
    .features-grid {
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    }
}

@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        height: auto;
        padding: var(--spacing-sm) var(--spacing-md);
    }
    
    .nav-menu {
        margin-top: var(--spacing-sm);
        flex-wrap: wrap;
        justify-content: center;
        gap: var(--spacing-md);
    }
    
    .hero {
        padding-top: 150px;
        text-align: center;
    }
    
    .hero-text h1 {
        font-size: var(--font-size-4xl);
    }
    
    .app-screenshots {
        height: 400px;
    }
    
    .phone-frame {
        width: 240px;
        height: 350px;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .feature-card {
        padding: var(--spacing-lg);
    }
    
    .contact-form {
        padding: var(--spacing-lg);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .hero-text h1 {
        font-size: var(--font-size-3xl);
    }
    
    .hero-text p {
        font-size: var(--font-size-base);
    }
    
    .features h2,
    .faq h2,
    .contact h2 {
        font-size: var(--font-size-3xl);
    }
    
    .phone-frame {
        width: 200px;
        height: 300px;
    }
    
    .screenshot-description {
        max-width: 250px;
    }
    
    .download-buttons {
        flex-direction: column;
        align-items: center;
    }
}

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

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

/* Scroll animations */
.fade-in-up {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

.fade-in-up.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Loading states */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

/* Success/Error messages */
.message {
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
    margin-bottom: var(--spacing-md);
    display: none;
}

.message.success {
    background: rgba(48, 209, 88, 0.1);
    color: var(--accent-green);
    border: 1px solid var(--accent-green);
}

.message.error {
    background: rgba(255, 59, 48, 0.1);
    color: var(--accent-red);
    border: 1px solid var(--accent-red);
}

/* Smooth scrolling for older browsers */
html {
    scroll-behavior: smooth;
}