/* 基础变量 - Light Mode (保留清爽感，但融入海洋色) */
:root {
    --primary-color: #0ea5e9; /* Deep ocean cobalt */
    --primary-hover: #0284c7;
    --bg-color: #f0f7ff;
    --text-color: #1e293b;
    --text-light: #475569;
    --card-bg: #ffffff;
    --border-color: #bae6fd;
    --header-bg: rgba(255, 255, 255, 0.85);
    --shadow: 0 4px 20px rgba(14, 165, 233, 0.08);
    --glow-effect: none;
    --transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
}

/* 暗黑模式变量 - Deep Oceanic Abyss */
[data-theme="dark"] {
    --primary-color: #00f2fe; /* Bioluminescent cyan */
    --primary-hover: #38bdf8;
    --bg-color: #050b14; /* Deep marine navy */
    --text-color: #e2e8f0;
    --text-light: #94a3b8;
    --card-bg: rgba(14, 165, 233, 0.04);
    --border-color: rgba(0, 242, 254, 0.15);
    --header-bg: rgba(5, 11, 20, 0.85);
    --shadow: 0 8px 32px rgba(0, 242, 254, 0.05);
    --glow-effect: 0 0 20px rgba(0, 242, 254, 0.2);
}

/* 重置与平滑滚动 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth; /* 锚点过渡动态效果 */
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color var(--transition), color var(--transition);
    overflow-x: hidden;
    position: relative;
}

/* 动态背景环境光 (深海颗粒感) */
.ambient-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    pointer-events: none;
    z-index: -1;
    background: radial-gradient(circle at 50% 0%, rgba(14, 165, 233, 0.15) 0%, transparent 50%);
    transition: opacity 1s;
}
[data-theme="dark"] .ambient-background {
    background: radial-gradient(circle at 50% 0%, rgba(0, 242, 254, 0.1) 0%, transparent 60%),
                radial-gradient(circle at 10% 80%, rgba(14, 165, 233, 0.05) 0%, transparent 40%);
}

/* 导航栏 */
header {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: var(--header-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--primary-color);
    letter-spacing: 1px;
    text-shadow: var(--glow-effect);
}

nav {
    display: flex;
    gap: 1.5rem;
}

nav a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

nav a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background-color: var(--primary-color);
    transition: var(--transition);
    box-shadow: var(--glow-effect);
}

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

nav a:hover::after {
    width: 100%;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* 昼夜切换按钮 */
.theme-toggle {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    cursor: pointer;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
    border-radius: 50%;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.theme-toggle:hover {
    box-shadow: var(--glow-effect);
    transform: scale(1.1);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
    transition: opacity 0.3s ease;
}

[data-theme="light"] .moon-icon { display: none; }
[data-theme="dark"] .sun-icon { display: none; }

/* 主视觉区 */
.hero {
    text-align: center;
    padding: 10rem 2rem 6rem;
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-content {
    max-width: 800px;
    animation: fadeUp 1s ease-out;
}

@keyframes fadeUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

.hero h1 {
    font-size: 3.8rem;
    margin-bottom: 1.5rem;
    line-height: 1.2;
    font-weight: 800;
}

.hero-highlight {
    background: linear-gradient(135deg, var(--primary-color), #38bdf8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: rgba(0, 242, 254, 0.3) 0px 0px 20px;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-light);
    margin-bottom: 3rem;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 0.8rem 2.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    text-align: center;
    transition: var(--transition);
    cursor: pointer;
    letter-spacing: 0.5px;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
    border: 1px solid var(--primary-color);
    box-shadow: 0 4px 15px rgba(14, 165, 233, 0.4);
}

[data-theme="dark"] .btn-primary {
    color: #050b14;
    box-shadow: 0 0 20px rgba(0, 242, 254, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    filter: brightness(1.1);
    box-shadow: 0 6px 20px rgba(14, 165, 233, 0.6);
}

[data-theme="dark"] .btn-primary:hover {
    box-shadow: 0 0 30px rgba(0, 242, 254, 0.6);
}

.btn-outline {
    background-color: transparent;
    color: var(--text-color);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(5px);
}

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

/* 卡片与流体发光效果 (Water-sheen border highlight) */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}
.dual-grid {
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
}

.card {
    background-color: var(--card-bg);
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 50%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    transform: skewX(-20deg);
    transition: 0.5s;
}
[data-theme="dark"] .card::before {
    background: linear-gradient(90deg, transparent, rgba(0, 242, 254, 0.15), transparent);
}

.card:hover {
    transform: translateY(-5px);
    border-color: var(--primary-color);
    box-shadow: var(--glow-effect);
}

.card:hover::before {
    left: 200%;
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    filter: drop-shadow(0 0 10px rgba(0, 242, 254, 0.5));
}

.card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.card p {
    color: var(--text-light);
    margin-bottom: 1.5rem;
}

/* 套餐卡片特调 */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    align-items: center;
}

.pricing-card {
    background-color: var(--card-bg);
    padding: 3rem 2rem;
    border-radius: 16px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    position: relative;
    backdrop-filter: blur(10px);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.pricing-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--glow-effect);
}

.pricing-card.popular {
    transform: scale(1.05);
    border: 2px solid var(--primary-color);
    background: linear-gradient(180deg, var(--card-bg) 0%, rgba(14, 165, 233, 0.05) 100%);
}

.pricing-card.popular:hover {
    transform: scale(1.05) translateY(-5px);
}

.badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--primary-color);
    color: #fff;
    padding: 0.3rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 700;
    box-shadow: var(--glow-effect);
}
[data-theme="dark"] .badge {
    color: #050b14;
}

/* 其他布局 */
section {
    max-width: 1200px;
    margin: 0 auto;
    padding: 6rem 2rem;
}

h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3.5rem;
    font-weight: 700;
}

.price {
    font-size: 3rem;
    font-weight: bold;
    color: var(--primary-color);
    margin: 1.5rem 0;
    text-shadow: var(--glow-effect);
}

.price span {
    font-size: 1rem;
    color: var(--text-light);
}

.pricing-card ul {
    list-style: none;
    margin-bottom: 2.5rem;
    flex-grow: 1;
}

.pricing-card ul li {
    padding: 0.8rem 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-light);
    display: flex;
    align-items: center;
}

.pricing-card ul li::before {
    content: "✓";
    color: var(--primary-color);
    margin-right: 10px;
    font-weight: bold;
}

/* FAQ 和评价 */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}
.faq-item {
    margin-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1.5rem;
}
.faq-item h4 {
    font-size: 1.2rem;
    margin-bottom: 0.8rem;
    color: var(--primary-color);
}
.faq-item p {
    color: var(--text-light);
}
.testimonial-card .user-info {
    font-weight: bold;
    color: var(--primary-color);
    margin-top: 1.5rem;
    text-align: right;
}

/* 页脚 */
footer {
    border-top: 1px solid var(--border-color);
    padding: 4rem 2rem;
    text-align: center;
    background-color: var(--header-bg);
}
.footer-links {
    margin-bottom: 1.5rem;
}
.footer-links a {
    color: var(--text-light);
    text-decoration: none;
    margin: 0 1.5rem;
    transition: var(--transition);
}
.footer-links a:hover {
    color: var(--primary-color);
}
.copyright {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* 响应式 */
@media (max-width: 768px) {
    .hero h1 { font-size: 2.5rem; }
    .hero p { font-size: 1.1rem; }
    .hero-buttons { flex-direction: column; }
    nav { display: none; }
    .pricing-card.popular { transform: scale(1); }
    .pricing-card.popular:hover { transform: translateY(-5px); }
    .dual-grid { grid-template-columns: 1fr; }
    .footer-links a { display: block; margin: 1rem 0; }
}