/* 全局重置与基础 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    transition: background var(--transition), color var(--transition);
}

a {
    color: var(--primary-light);
    text-decoration: none;
}

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

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

/* 颜色变量与暗色模式 */
:root {
    --primary: #1a3a5c;
    --primary-light: #2a5a8c;
    --secondary: #e8a838;
    --accent: #f0c060;
    --bg: #f5f7fa;
    --text: #1a1a2e;
    --glass: rgba(255,255,255,0.15);
    --shadow: 0 8px 32px rgba(0,0,0,0.1);
    --radius: 16px;
    --transition: 0.3s ease;
}

[data-theme="dark"] {
    --primary: #0d1b2a;
    --primary-light: #1b3a5c;
    --secondary: #d4a030;
    --accent: #c09030;
    --bg: #121212;
    --text: #e0e0e0;
    --glass: rgba(0,0,0,0.3);
    --shadow: 0 8px 32px rgba(0,0,0,0.5);
}

/* Header - 毛玻璃效果 */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: var(--shadow);
    transition: background var(--transition), box-shadow var(--transition);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
}

.logo svg {
    width: 40px;
    height: 40px;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 24px;
}

nav a {
    padding: 8px 0;
    font-weight: 500;
    position: relative;
    color: var(--text);
    transition: color var(--transition);
}

nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--secondary);
    transition: width var(--transition);
}

nav a:hover::after,
nav a.active::after {
    width: 100%;
}

nav a.active {
    color: var(--secondary);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

.dark-toggle {
    background: none;
    border: 2px solid var(--primary);
    border-radius: 50%;
    width: 36px;
    height: 36px;
    cursor: pointer;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
}

.dark-toggle:hover {
    background: var(--primary);
    color: #fff;
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.8rem;
    cursor: pointer;
    color: var(--text);
}

/* Hero - 渐变Banner */
.hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: #fff;
    padding: 80px 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 30% 50%, rgba(232,168,56,0.2) 0%, transparent 50%);
    animation: heroGlow 8s ease-in-out infinite;
}

@keyframes heroGlow {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(10%, 10%); }
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 3.2rem;
    margin-bottom: 20px;
    letter-spacing: 2px;
}

.hero p {
    font-size: 1.2rem;
    max-width: 700px;
    margin: 0 auto 30px;
    opacity: 0.9;
}

.hero .btn {
    display: inline-block;
    padding: 14px 40px;
    background: var(--secondary);
    color: var(--primary);
    border-radius: 50px;
    font-weight: 600;
    font-size: 1.1rem;
    transition: transform var(--transition), box-shadow var(--transition);
}

.hero .btn:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px rgba(0,0,0,0.3);
}

.hero .carousel {
    margin-top: 40px;
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

.hero .carousel-item {
    background: var(--glass);
    backdrop-filter: blur(10px);
    border-radius: var(--radius);
    padding: 20px 30px;
    min-width: 200px;
    transition: transform var(--transition);
}

.hero .carousel-item:hover {
    transform: scale(1.05);
}

/* Sections */
section {
    padding: 60px 0;
}

.section-title {
    text-align: center;
    margin-bottom: 40px;
}

.section-title h2 {
    font-size: 2.2rem;
    color: var(--primary);
    position: relative;
    display: inline-block;
}

.section-title h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--secondary);
    margin: 10px auto 0;
    border-radius: 2px;
}

.grid-2, .grid-3, .grid-4 {
    display: grid;
    gap: 30px;
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* 圆角卡片 + 毛玻璃 + hover动画 */
.card {
    background: var(--glass);
    backdrop-filter: blur(10px);
    border-radius: var(--radius);
    padding: 30px;
    box-shadow: var(--shadow);
    transition: transform var(--transition), box-shadow var(--transition);
}

.card:hover {
    transform: translateY(-8px);
    box-shadow: 0 16px 48px rgba(0,0,0,0.15);
}

.card h3 {
    color: var(--primary);
    margin-bottom: 12px;
}

.card p {
    opacity: 0.85;
}

.card svg {
    width: 48px;
    height: 48px;
    margin-bottom: 16px;
    fill: var(--secondary);
}

/* FAQ */
.faq-item {
    border-bottom: 1px solid rgba(0,0,0,0.1);
    padding: 16px 0;
    cursor: pointer;
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    font-size: 1.1rem;
}

.faq-question span {
    transition: transform var(--transition);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
    padding-top: 0;
    color: #555;
}

.faq-item.active .faq-answer {
    max-height: 300px;
    padding-top: 12px;
}

.faq-item.active .faq-question span {
    transform: rotate(45deg);
}

/* HowTo */
.howto-steps {
    counter-reset: step;
}

.howto-step {
    display: flex;
    gap: 20px;
    margin-bottom: 30px;
    align-items: flex-start;
}

.howto-step::before {
    counter-increment: step;
    content: counter(step);
    width: 40px;
    height: 40px;
    background: var(--secondary);
    color: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

/* Article */
.article-card {
    border-bottom: 1px solid rgba(0,0,0,0.08);
    padding: 20px 0;
}

.article-card h3 {
    font-size: 1.3rem;
}

.article-card .meta {
    font-size: 0.9rem;
    color: #888;
    margin: 8px 0;
}

.article-card .read-more {
    color: var(--secondary);
    font-weight: 600;
}

/* Footer */
footer {
    background: var(--primary);
    color: #ccc;
    padding: 40px 0 20px;
}

footer .container {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

footer h4 {
    color: #fff;
    margin-bottom: 16px;
}

footer a {
    color: #aaa;
    display: block;
    margin-bottom: 8px;
}

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

footer .bottom {
    grid-column: 1 / -1;
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 20px;
    text-align: center;
    font-size: 0.9rem;
}

/* Back to top */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    background: var(--secondary);
    color: var(--primary);
    border: none;
    border-radius: 50%;
    font-size: 1.5rem;
    cursor: pointer;
    box-shadow: var(--shadow);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition);
    z-index: 999;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: scale(1.1);
}

/* 滚动动画 */
.fade-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

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

.count-up {
    display: inline-block;
}

/* Search modal */
.search-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.6);
    z-index: 2000;
    justify-content: center;
    align-items: center;
}

.search-modal.open {
    display: flex;
}

.search-modal-content {
    background: var(--bg);
    padding: 40px;
    border-radius: var(--radius);
    width: 90%;
    max-width: 500px;
}

.search-modal input {
    width: 100%;
    padding: 12px 20px;
    border: 2px solid var(--primary);
    border-radius: 50px;
    font-size: 1rem;
    outline: none;
}

/* 响应式布局 */
@media (max-width: 1024px) {
    .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    nav ul {
        display: none;
        flex-direction: column;
        background: var(--glass);
        backdrop-filter: blur(20px);
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        padding: 20px;
        gap: 12px;
        box-shadow: var(--shadow);
    }

    nav.open ul {
        display: flex;
    }

    .menu-toggle {
        display: block;
    }

    .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
    }

    .hero h1 {
        font-size: 2rem;
    }

    footer .container {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 480px) {
    footer .container {
        grid-template-columns: 1fr;
    }
}