:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

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

/* Navigation */
.navbar {
    background: var(--bg-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 1rem 0;
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo h1 {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    padding: 0.625rem 1.25rem;
    border-radius: 0.5rem;
    transition: all 0.3s;
    position: relative;
}

.nav-links a:hover {
    color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

.nav-links a:active {
    transform: scale(0.98);
}

.nav-links .web-link {
    background: var(--primary-color);
    color: white;
    padding: 0.5rem 1.5rem;
    border-radius: 0.5rem;
    transition: background 0.3s;
}

.nav-links .web-link:hover {
    background: var(--primary-dark);
    color: white;
}

.lang-switcher {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.625rem 1.25rem;
    border-radius: 0.5rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 1rem;
    font-family: inherit;
}

.lang-switcher:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.lang-switcher:active {
    transform: scale(0.98);
}

.lang-switcher.mobile {
    width: 100%;
    text-align: left;
    margin-top: 0.5rem;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all 0.3s;
}

.mobile-menu {
    display: none;
    flex-direction: column;
    gap: 1rem;
    padding: 1rem 0;
    background: var(--bg-white);
    border-top: 1px solid var(--border-color);
}

.mobile-menu.active {
    display: flex;
}

.mobile-menu a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    padding: 0.875rem 1rem;
    border-radius: 0.5rem;
    transition: all 0.3s;
    display: block;
}

.mobile-menu a:hover {
    color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    min-height: 80vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: white;
    color: var(--primary-color);
}

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

.btn-secondary {
    background: rgba(255, 255, 255, 0.2);
    color: white;
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

/* 在下载区域中的按钮样式 */
.download .btn-primary {
    background: var(--primary-color);
    color: white;
}

.download .btn-primary:hover {
    background: var(--primary-dark);
    color: white;
    box-shadow: var(--shadow-lg);
}

.download .btn-secondary {
    background: var(--primary-color);
    color: white;
    backdrop-filter: none;
}

.download .btn-secondary:hover {
    background: var(--primary-dark);
    color: white;
    box-shadow: var(--shadow-lg);
}

.btn-outline {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-outline:hover {
    background: white;
    color: var(--primary-color);
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.phone-mockup {
    width: 280px;
    height: 560px;
    background: #1f2937;
    border-radius: 2.5rem;
    padding: 1rem;
    box-shadow: var(--shadow-xl);
    position: relative;
}

.phone-screen {
    width: 100%;
    height: 100%;
    background: white;
    border-radius: 2rem;
    overflow: hidden;
    position: relative;
}

.app-preview {
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
}

/* Features Section */
.features {
    padding: 5rem 0;
    background: var(--bg-light);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s, box-shadow 0.3s;
    text-align: center;
}

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

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

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

/* Download Section */
.download {
    padding: 5rem 0;
    background: white;
}

.download-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.download-option {
    background: var(--bg-light);
    padding: 3rem;
    border-radius: 1.5rem;
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}

.download-option:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.download-icon {
    font-size: 4rem;
    margin-bottom: 1.5rem;
}

.download-option h3 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.download-option > p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.6;
    min-height: 3rem;
}

.android-tip {
    color: var(--primary-color);
    font-weight: 500;
    margin-bottom: 1rem;
    padding: 1rem;
    background: rgba(99, 102, 241, 0.1);
    border-radius: 0.5rem;
}

.android-desktop-msg,
.android-mobile-msg,
#androidDefaultMsg {
    margin-top: 1rem;
}

.download-note {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: 1rem;
    font-style: italic;
}

.android-instructions {
    margin-top: 2rem;
    text-align: left;
    background: white;
    padding: 1.5rem;
    border-radius: 0.75rem;
}

.android-instructions h4 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-size: 1.25rem;
}

.instruction-step {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.instruction-step:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.instruction-step > p:first-child {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.instruction-step > p:not(:first-child) {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 0.5rem;
}

.instruction-step ol {
    margin-left: 1.5rem;
    margin-top: 0.5rem;
    margin-bottom: 1rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.instruction-step ol li {
    margin-bottom: 0.5rem;
}

.browser-instructions {
    margin-top: 1rem;
}

.browser-instructions > p {
    font-weight: 600;
    color: var(--text-primary);
    margin-top: 1rem;
    margin-bottom: 0.5rem;
}

.browser-instructions > p:first-child {
    margin-top: 0;
}

.browser-instructions ol {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.browser-instructions ol li {
    margin-bottom: 0.5rem;
}

.android-instructions strong {
    color: var(--primary-color);
    font-weight: 600;
}

/* Web Version Section */
.web-version {
    padding: 4rem 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    text-align: center;
}

.web-version-content h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.web-version-content p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
}

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

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: white;
}

.footer-section p {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
}

/* Responsive Design */
@media (max-width: 968px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .phone-mockup {
        width: 240px;
        height: 480px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .hero {
        padding: 2rem 0;
        min-height: auto;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .download-content {
        grid-template-columns: 1fr;
    }

    .download-option {
        padding: 2rem 1.5rem;
    }

    .android-instructions {
        padding: 1.25rem;
    }

    .android-instructions h4 {
        font-size: 1.1rem;
    }

    .instruction-step > p:first-child {
        font-size: 1rem;
    }

    .web-version-content h2 {
        font-size: 1.75rem;
    }

    .web-version-content p {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .hero-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        text-align: center;
    }

    .phone-mockup {
        width: 200px;
        height: 400px;
    }
}

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