/* ===== 全局重置与基础样式 ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --color-bg: #0f0f1a;
    --color-bg-alt: #1a1a2e;
    --color-surface: rgba(255,255,255,0.05);
    --color-surface-hover: rgba(255,255,255,0.1);
    --color-text: #e0e0e0;
    --color-text-secondary: #a0a0b0;
    --color-accent: #f0c040;
    --color-accent-hover: #ffd966;
    --color-glass: rgba(255,255,255,0.08);
    --color-glass-border: rgba(255,255,255,0.15);
    --color-glass-shadow: rgba(0,0,0,0.3);
    --color-gradient-1: #1a1a2e;
    --color-gradient-2: #16213e;
    --color-gradient-3: #0f3460;
    --color-gradient-4: #533483;
    --font-primary: 'Segoe UI', system-ui, -apple-system, sans-serif;
    --transition-speed: 0.3s;
    --border-radius: 16px;
    --max-width: 1200px;
    --header-height: 70px;
}

/* 亮色模式 */
[data-theme="light"] {
    --color-bg: #f5f5fa;
    --color-bg-alt: #ffffff;
    --color-surface: rgba(0,0,0,0.03);
    --color-surface-hover: rgba(0,0,0,0.06);
    --color-text: #1a1a2e;
    --color-text-secondary: #5a5a6e;
    --color-glass: rgba(255,255,255,0.7);
    --color-glass-border: rgba(0,0,0,0.1);
    --color-glass-shadow: rgba(0,0,0,0.08);
    --color-gradient-1: #667eea;
    --color-gradient-2: #764ba2;
    --color-gradient-3: #f093fb;
    --color-gradient-4: #f5576c;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition-speed);
}
a:hover {
    color: var(--color-accent-hover);
}

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

ul, ol {
    list-style: none;
}

/* ===== 滚动动画基础 ===== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== 头部导航 ===== */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: var(--color-glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-glass-border);
    box-shadow: 0 4px 20px var(--color-glass-shadow);
    height: var(--header-height);
    transition: background var(--transition-speed);
}

nav {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
}

nav > div:first-child a {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--color-text);
    letter-spacing: 0.5px;
}
nav > div:first-child a:hover {
    color: var(--color-accent);
}

nav ul {
    display: flex;
    gap: 8px;
    align-items: center;
    flex-wrap: wrap;
}

nav ul li a {
    padding: 8px 14px;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    transition: all var(--transition-speed);
    position: relative;
}
nav ul li a::after {
    content: '';
    position: absolute;
    bottom: 2px;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 60%;
    height: 2px;
    background: var(--color-accent);
    transition: transform var(--transition-speed);
    border-radius: 2px;
}
nav ul li a:hover {
    color: var(--color-accent);
    background: var(--color-surface);
}
nav ul li a:hover::after {
    transform: translateX(-50%) scaleX(1);
}

nav > div:nth-child(3) {
    display: flex;
    gap: 10px;
    align-items: center;
}

nav > div:nth-child(3) a {
    padding: 8px 20px;
    border-radius: 30px;
    font-size: 0.9rem;
    font-weight: 600;
    transition: all var(--transition-speed);
    display: inline-flex;
    align-items: center;
    justify-content: center;
}
nav > div:nth-child(3) a:first-child {
    background: transparent;
    border: 1px solid var(--color-accent);
    color: var(--color-accent);
}
nav > div:nth-child(3) a:first-child:hover {
    background: var(--color-accent);
    color: #1a1a2e;
    box-shadow: 0 0 20px rgba(240,192,64,0.3);
}
nav > div:nth-child(3) a:last-child {
    background: linear-gradient(135deg, var(--color-accent), #e6a800);
    color: #1a1a2e;
    border: none;
}
nav > div:nth-child(3) a:last-child:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(240,192,64,0.4);
}

#darkModeToggle, #mobileMenuToggle {
    background: var(--color-surface);
    border: 1px solid var(--color-glass-border);
    border-radius: 10px;
    padding: 8px 12px;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all var(--transition-speed);
    color: var(--color-text);
    display: flex;
    align-items: center;
    justify-content: center;
}
#darkModeToggle:hover, #mobileMenuToggle:hover {
    background: var(--color-surface-hover);
    transform: scale(1.05);
}

#mobileMenuToggle {
    display: none;
}

/* ===== Hero 区域 ===== */
#hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 120px 20px 80px;
    position: relative;
    overflow: hidden;
    background: linear-gradient(135deg, var(--color-gradient-1), var(--color-gradient-2), var(--color-gradient-3), var(--color-gradient-4));
    background-size: 400% 400%;
    animation: gradientShift 15s ease infinite;
}

@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

#hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 30% 50%, rgba(255,255,255,0.03) 0%, transparent 50%);
    animation: float 20s ease-in-out infinite;
    pointer-events: none;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    33% { transform: translate(30px, -20px) rotate(2deg); }
    66% { transform: translate(-20px, 30px) rotate(-2deg); }
}

#hero > div {
    max-width: 800px;
    position: relative;
    z-index: 1;
}

#hero h1 {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;
    margin-bottom: 20px;
    line-height: 1.2;
    background: linear-gradient(to right, #fff, var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: none;
}

#hero p {
    font-size: clamp(1rem, 2vw, 1.2rem);
    color: rgba(255,255,255,0.85);
    margin-bottom: 30px;
    max-width: 650px;
    margin-left: auto;
    margin-right: auto;
}

#hero > div > div:first-of-type {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 40px;
}

#hero > div > div:first-of-type a {
    padding: 14px 36px;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 700;
    transition: all var(--transition-speed);
    display: inline-flex;
    align-items: center;
    gap: 8px;
}
#hero > div > div:first-of-type a:first-child {
    background: var(--color-accent);
    color: #1a1a2e;
    box-shadow: 0 8px 30px rgba(240,192,64,0.3);
}
#hero > div > div:first-of-type a:first-child:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 40px rgba(240,192,64,0.5);
}
#hero > div > div:first-of-type a:last-child {
    background: rgba(255,255,255,0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.2);
    color: #fff;
}
#hero > div > div:first-of-type a:last-child:hover {
    background: rgba(255,255,255,0.2);
    transform: translateY(-3px);
}

#hero > div > div:last-of-type {
    display: flex;
    gap: 30px;
    justify-content: center;
    flex-wrap: wrap;
    font-size: 0.9rem;
    color: rgba(255,255,255,0.7);
}
#hero > div > div:last-of-type span {
    display: flex;
    align-items: center;
    gap: 6px;
}

/* ===== 通用 Section 样式 ===== */
section {
    padding: 80px 20px;
    max-width: var(--max-width);
    margin: 0 auto;
}

section h2 {
    font-size: clamp(1.8rem, 3vw, 2.5rem);
    font-weight: 700;
    margin-bottom: 20px;
    text-align: center;
    position: relative;
    display: inline-block;
    left: 50%;
    transform: translateX(-50%);
}
section h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--color-accent), transparent);
    margin: 10px auto 0;
    border-radius: 4px;
}

section > p {
    text-align: center;
    color: var(--color-text-secondary);
    max-width: 700px;
    margin: 0 auto 40px;
    font-size: 1.05rem;
}

/* ===== About 区域 ===== */
#about {
    background: var(--color-bg-alt);
    border-radius: var(--border-radius);
    margin: 0 20px;
    padding: 60px 30px;
    max-width: calc(var(--max-width) - 40px);
    box-shadow: 0 10px 40px rgba(0,0,0,0.1);
}

#about p {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 20px;
    color: var(--color-text-secondary);
}

/* ===== Products / Services / Features 卡片网格 ===== */
#products > div,
#services > div,
#features > div {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin-top: 20px;
}

#products article,
#services article,
#features > div > div {
    background: var(--color-glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--color-glass-border);
    border-radius: var(--border-radius);
    padding: 30px 24px;
    transition: all var(--transition-speed);
    box-shadow: 0 8px 32px var(--color-glass-shadow);
    position: relative;
    overflow: hidden;
}

#products article::before,
#services article::before,
#features > div > div::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--color-accent), var(--color-accent-hover), transparent);
    opacity: 0;
    transition: opacity var(--transition-speed);
}

#products article:hover::before,
#services article:hover::before,
#features > div > div:hover::before {
    opacity: 1;
}

#products article:hover,
#services article:hover,
#features > div > div:hover {
    transform: translateY(-8px);
    box-shadow: 0 16px 48px var(--color-glass-shadow);
    border-color: var(--color-accent);
}

#products article h3,
#services article h3,
#features > div > div h3 {
    font-size: 1.3rem;
    margin-bottom: 12px;
    color: var(--color-accent);
}

#products article p,
#services article p,
#features > div > div p {
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* ===== HowTo 步骤 ===== */
#howto {
    background: var(--color-bg-alt);
    border-radius: var(--border-radius);
    margin: 0 20px;
    padding: 60px 30px;
    max-width: calc(var(--max-width) - 40px);
}

#howto ol {
    max-width: 700px;
    margin: 30px auto 0;
    counter-reset: step;
}

#howto ol li {
    counter-increment: step;
    padding: 18px 20px 18px 60px;
    position: relative;
    background: var(--color-surface);
    border-radius: 12px;
    margin-bottom: 12px;
    border-left: 3px solid var(--color-accent);
    transition: all var(--transition-speed);
    font-size: 1rem;
}

#howto ol li::before {
    content: counter(step);
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    width: 30px;
    height: 30px;
    background: var(--color-accent);
    color: #1a1a2e;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.9rem;
}

#howto ol li:hover {
    background: var(--color-surface-hover);
    transform: translateX(5px);
}

#howto ol li strong {
    color: var(--color-accent);
    margin-right: 4px;
}

/* ===== FAQ 折叠面板 ===== */
#faq > div {
    max-width: 800px;
    margin: 30px auto 0;
}

#faq details {
    background: var(--color-glass);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--color-glass-border);
    border-radius: 12px;
    margin-bottom: 10px;
    overflow: hidden;
    transition: all var(--transition-speed);
}

#faq details:hover {
    border-color: var(--color-accent);
    box-shadow: 0 4px 20px var(--color-glass-shadow);
}

#faq details summary {
    padding: 16px 20px;
    cursor: pointer;
    font-weight: 600;
    font-size: 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    list-style: none;
    color: var(--color-text);
    transition: color var(--transition-speed);
}

#faq details summary::-webkit-details-marker {
    display: none;
}

#faq details summary::after {
    content: '▼';
    font-size: 0.7rem;
    transition: transform var(--transition-speed);
    color: var(--color-accent);
}

#faq details[open] summary::after {
    transform: rotate(180deg);
}

#faq details summary:hover {
    color: var(--color-accent);
}

#faq details p {
    padding: 0 20px 16px;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* ===== 知识中心 ===== */
#knowledge > div {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

#knowledge article {
    background: var(--color-glass);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--color-glass-border);
    border-radius: var(--border-radius);
    padding: 24px;
    transition: all var(--transition-speed);
    display: flex;
    flex-direction: column;
}

#knowledge article:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px var(--color-glass-shadow);
    border-color: var(--color-accent);
}

#knowledge article h3 {
    font-size: 1.15rem;
    margin-bottom: 10px;
    color: var(--color-accent);
}

#knowledge article p {
    color: var(--color-text-secondary);
    line-height: 1.7;
    flex: 1;
    margin-bottom: 16px;
}

#knowledge article a {
    align-self: flex-start;
    padding: 8px 20px;
    border-radius: 30px;
    background: linear-gradient(135deg, var(--color-accent), #e6a800);
    color: #1a1a2e;
    font-weight: 600;
    font-size: 0.85rem;
    transition: all var(--transition-speed);
}

#knowledge article a:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(240,192,64,0.3);
}

/* ===== 联系区域 ===== */
#contact {
    background: var(--color-bg-alt);
    border-radius: var(--border-radius);
    margin: 0 20px;
    padding: 60px 30px;
    max-width: calc(var(--max-width) - 40px);
    text-align: center;
}

#contact address {
    font-style: normal;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    max-width: 800px;
    margin: 30px auto 0;
}

#contact address p {
    background: var(--color-surface);
    padding: 16px;
    border-radius: 12px;
    border: 1px solid var(--color-glass-border);
    transition: all var(--transition-speed);
    font-size: 0.95rem;
}

#contact address p:hover {
    background: var(--color-surface-hover);
    transform: translateY(-3px);
    border-color: var(--color-accent);
}

/* ===== 页脚 ===== */
footer {
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-glass-border);
    padding: 60px 20px 20px;
    margin-top: 40px;
}

footer > div:first-child {
    max-width: var(--max-width);
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 30px;
}

footer h3 {
    font-size: 1.1rem;
    margin-bottom: 16px;
    color: var(--color-accent);
}

footer p {
    color: var(--color-text-secondary);
    line-height: 1.7;
}

footer ul li {
    margin-bottom: 8px;
}

footer ul li a {
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    transition: all var(--transition-speed);
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

footer ul li a::before {
    content: '›';
    color: var(--color-accent);
    font-weight: 700;
    transition: transform var(--transition-speed);
}

footer ul li a:hover {
    color: var(--color-accent);
    transform: translateX(4px);
}

footer > div:last-child {
    max-width: var(--max-width);
    margin: 40px auto 0;
    padding-top: 20px;
    border-top: 1px solid var(--color-glass-border);
    text-align: center;
    color: var(--color-text-secondary);
    font-size: 0.85rem;
}

/* ===== 响应式设计 ===== */
@media (max-width: 768px) {
    :root {
        --header-height: 60px;
    }

    nav ul {
        display: none;
        position: absolute;
        top: var(--header-height);
        left: 0;
        width: 100%;
        background: var(--color-glass);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        border-bottom: 1px solid var(--color-glass-border);
        flex-direction: column;
        padding: 20px;
        gap: 4px;
        box-shadow: 0 20px 40px var(--color-glass-shadow);
    }

    nav ul.open {
        display: flex;
    }

    nav ul li a {
        width: 100%;
        text-align: center;
        padding: 12px;
        font-size: 1rem;
    }

    #mobileMenuToggle {
        display: flex;
    }

    nav > div:nth-child(3) a {
        padding: 6px 14px;
        font-size: 0.8rem;
    }

    #hero {
        padding: 100px 16px 60px;
    }

    section {
        padding: 50px 16px;
    }

    #about, #howto, #contact {
        margin: 0 10px;
        padding: 40px 20px;
    }

    #products > div,
    #services > div,
    #features > div,
    #knowledge > div {
        grid-template-columns: 1fr;
    }

    #contact address {
        grid-template-columns: 1fr;
    }

    footer > div:first-child {
        grid-template-columns: 1fr;
        text-align: center;
    }

    footer ul li a {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    nav {
        padding: 0 12px;
        gap: 8px;
    }

    nav > div:first-child a {
        font-size: 1rem;
    }

    #hero h1 {
        font-size: 1.8rem;
    }

    #hero p {
        font-size: 0.95rem;
    }

    #hero > div > div:first-of-type a {
        padding: 12px 24px;
        font-size: 0.9rem;
    }

    section h2 {
        font-size: 1.5rem;
    }

    #howto ol li {
        padding: 14px 14px 14px 50px;
        font-size: 0.9rem;
    }

    #howto ol li::before {
        width: 26px;
        height: 26px;
        font-size: 0.8rem;
        left: 12px;
    }
}

/* ===== 滚动动画触发 (使用 Intersection Observer 的备用方案) ===== */
@media (prefers-reduced-motion: no-preference) {
    .fade-in {
        opacity: 0;
        transform: translateY(30px);
        transition: opacity 0.6s ease-out, transform 0.6s ease-out;
    }
    .fade-in.visible {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (prefers-reduced-motion: reduce) {
    .fade-in {
        opacity: 1 !important;
        transform: none !important;
    }
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}