:root {
    --bg-color: #FFFFFF;
    --bg-secondary: #F2F4F8;
    --card-bg: #FFFFFF;
    --text-primary: #1C1C1E;
    --text-secondary: #8E8E93;
    --accent-black: #1C1C1E;
    --accent-green: #34C759;
    --border-radius: 24px;
    --shadow: 0 8px 24px rgba(0,0,0,0.04);
    --shadow-lg: 0 16px 48px rgba(0,0,0,0.08);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

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

/* å¯¼èˆªæ  */
nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 20px 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(0,0,0,0.05);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 24px;
    font-weight: 800;
    letter-spacing: -0.5px;
    color: var(--text-primary);
    text-decoration: none;
}

.logo-icon {
    width: 32px;
    height: 32px;
    background: var(--accent-black);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 700;
    font-size: 18px;
}

.logo-img {
    height: 32px;
    width: auto;
    display: block;
    object-fit: contain;
}

.nav-links {
    display: flex;
    gap: 32px;
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--text-primary);
}

.nav-cta {
    background: var(--accent-black);
    color: white;
    padding: 10px 24px;
    border-radius: 20px;
    font-weight: 600;
    transition: transform 0.2s, box-shadow 0.2s;
}

.nav-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    color: white;
}

/* 语言切换器 */
.language-switcher {
    position: relative;
    display: inline-block;
}

.language-btn {
    background: transparent;
    border: 1px solid rgba(0,0,0,0.1);
    color: var(--text-primary);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s;
}

.language-btn:hover {
    background: var(--bg-secondary);
    border-color: rgba(0,0,0,0.2);
}

.language-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 8px;
    background: white;
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.12);
    min-width: 120px;
    overflow: hidden;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s;
    z-index: 1001;
}

.language-dropdown.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-option {
    padding: 12px 20px;
    cursor: pointer;
    transition: background 0.2s;
    font-size: 14px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.language-option:hover {
    background: var(--bg-secondary);
}

.language-option.active {
    background: var(--bg-secondary);
    font-weight: 600;
}

/* 页脚 */
footer {
    background: var(--accent-black);
    color: white;
    padding: 60px 40px 40px;
    margin-top: 80px;
}

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

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 48px;
    margin-bottom: 48px;
}

.footer-section h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 16px;
}

.footer-section a {
    display: block;
    color: rgba(255,255,255,0.7);
    text-decoration: none;
    margin-bottom: 12px;
    font-size: 14px;
    transition: color 0.3s;
}

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

.footer-section-center {
    text-align: center;
}

.social-links {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    justify-content: center;
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: rgba(255,255,255,0.1);
    border-radius: 50%;
    color: rgba(255,255,255,0.7);
    text-decoration: none;
    transition: all 0.3s;
    font-size: 18px;
    flex-shrink: 0;
}

.social-link i {
    line-height: 1;
    margin: 0;
    padding: 0;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1em;
    height: 1em;
}

.social-link:hover {
    background: rgba(255,255,255,0.2);
    color: white;
    transform: translateY(-2px);
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 32px;
    text-align: center;
    color: rgba(255,255,255,0.7);
    font-size: 14px;
}

@media (max-width: 768px) {
    .nav-container {
        padding: 0 20px;
    }

    .nav-links a:not(.nav-cta) {
        display: none;
    }

    .language-switcher {
        display: block;
    }
}

.nav-scroll-effect {
    transition: background 0.3s;
}