:root[data-theme="dark"] {
    --bg-base: #0d1117;
    --bg-card: rgba(22, 27, 34, 0.65);
    --border-color: rgba(48, 54, 61, 0.8);
    --text-primary: #c9d1d9;
    --text-secondary: #8b949e;
    --accent-color: #58a6ff;
    --accent-hover: #3182ce;
    --btn-bg: rgba(33, 38, 45, 0.8);
    --btn-hover: rgba(48, 54, 61, 1);
    --fission-core: rgba(163, 113, 247, 0.15);
    --fission-ring: rgba(88, 166, 255, 0.1);
}

:root[data-theme="light"] {
    --bg-base: #f0f4f8;
    --bg-card: rgba(255, 255, 255, 0.7);
    --border-color: rgba(226, 232, 240, 0.8);
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --accent-color: #2563eb;
    --accent-hover: #1d4ed8;
    --btn-bg: rgba(241, 245, 249, 0.8);
    --btn-hover: rgba(226, 232, 240, 1);
    --fission-core: rgba(139, 92, 246, 0.15);
    --fission-ring: rgba(59, 130, 246, 0.1);
}

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

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background-color: var(--bg-base);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color 0.4s ease, color 0.4s ease;
    overflow-x: hidden;
}

/* Fission Background */
.fission-bg {
    position: fixed;
    top: 0; left: 0; width: 100vw; height: 100vh;
    z-index: -1; overflow: hidden;
    background: var(--bg-base);
    transition: background 0.4s ease;
}
.fission-bg::before, .fission-bg::after {
    content: ''; position: absolute; top: -50%; left: -50%; width: 200%; height: 200%;
    transform-origin: center; pointer-events: none;
}
.fission-bg::before {
    background: conic-gradient(from 0deg, transparent, var(--fission-ring), transparent 30%, var(--fission-core), transparent 60%);
    animation: spiralSpin 25s linear infinite; filter: blur(80px);
}
.fission-bg::after {
    background: radial-gradient(circle at center, var(--accent-color) 0%, transparent 40%);
    opacity: 0.15;
    animation: fissionPulse 12s ease-in-out infinite alternate, spiralSpinRev 35s linear infinite;
    mix-blend-mode: screen;
}

@keyframes spiralSpin { 100% { transform: rotate(360deg); } }
@keyframes spiralSpinRev { 100% { transform: rotate(-360deg); } }
@keyframes fissionPulse {
    0% { transform: scale(1); opacity: 0.1; }
    50% { transform: scale(1.3) rotate(180deg); opacity: 0.3; }
    100% { transform: scale(0.9) rotate(360deg); opacity: 0.1; }
}

.container { width: 90%; max-width: 1200px; margin: 0 auto; }

/* Navbar - 整体布局微调以适应并排 */
.navbar {
    background: rgba(var(--bg-base), 0.5); backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
    position: sticky; top: 0; z-index: 100; padding: 0.75rem 0; /* 略微减小上下内边距 */
}
.nav-container { display: flex; justify-content: space-between; align-items: center; gap: 0.5rem; } /* 减小整体间距 */

.logo-group { display: flex; align-items: center; gap: 1rem; } /* 减小 LOGO 和 Tab 之间的间距 */

/* 修改点 2: 图片 LOGO 样式，限定高度以减小尺寸 */
.logo { display: flex; align-items: center; text-decoration: none; }
.logo-img {
    height: 24px; /* 限定高度，精致小巧 */
    width: auto; /* 宽度自适应 */
    display: block;
}

/* Tabs - 核心修改点：减小字号以实现并排 */
.nav-links { display: flex; gap: 0.75rem; align-items: center; } /* 减小 Tab 之间的间距 */
.nav-tab {
    color: var(--text-primary);
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    padding: 2px 0;
    border-bottom: 2px solid transparent;
    /* 修改点 3: 显著减小字号 */
    font-size: 0.85rem; /* 从默认 1rem 减小，确保移动端也能并排 */
    font-weight: 500; /* 稍微降低字重，看起来更秀气 */
    white-space: nowrap; /* 强制不换行 */
}
.nav-tab:hover { color: var(--accent-color); }
.nav-tab.active { color: var(--accent-color); border-bottom: 2px solid var(--accent-color); font-weight: 600; }

/* 右侧控制区微调 */
.nav-controls { display: flex; align-items: center; gap: 0.75rem; }
.lang-selector {
    display: flex; align-items: center; gap: 0.3rem;
    background: var(--btn-bg); padding: 0.4rem 0.6rem;
    border-radius: 10px; border: 1px solid var(--border-color);
}
.lang-selector i { font-size: 0.8rem; color: var(--text-secondary); }
.lang-selector select { background: transparent; color: var(--text-primary); border: none; outline: none; font-size: 0.8rem; cursor: pointer; font-weight: 600; }

.theme-btn {
    background: var(--btn-bg); color: var(--text-primary); border: 1px solid var(--border-color); border-radius: 10px;
    width: 34px; height: 34px; cursor: pointer; display: flex; justify-content: center; align-items: center; transition: all 0.3s ease; font-size: 0.9rem;
}
.theme-btn:hover { background: var(--btn-hover); transform: scale(1.05); }

/* Hero */
.hero { text-align: center; padding: 4rem 0 3rem; position: relative; z-index: 1; }
.hero h1 {
    font-size: clamp(2.2rem, 5vw, 3.8rem); font-weight: 800; margin-bottom: 1rem;
    background: linear-gradient(90deg, var(--accent-color), #a371f7);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.hero p { font-size: 1.15rem; color: var(--text-secondary); max-width: 700px; margin: 0 auto; }

/* Grid */
.client-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 1.5rem; padding-bottom: 5rem; }
.card {
    background: var(--bg-card); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-color); border-radius: 16px; padding: 2rem;
    display: flex; flex-direction: column; transition: all 0.3s ease; box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.card:hover { transform: translateY(-5px); border-color: var(--accent-color); box-shadow: 0 12px 30px rgba(0, 0, 0, 0.15); }
.card-header { display: flex; align-items: center; gap: 1rem; margin-bottom: 1rem; }
.card-header i { font-size: 2.5rem; color: var(--text-primary); }
.card-title h3 { font-size: 1.25rem; color: var(--text-primary); }
.card-title span { font-size: 0.85rem; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 1px; }
.card-desc { color: var(--text-secondary); margin-bottom: 1.5rem; flex-grow: 1; font-size: 0.95rem; }
.card-actions { display: flex; flex-wrap: wrap; gap: 0.75rem; }
.btn {
    flex: 1 1 calc(50% - 0.75rem); display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem;
    padding: 0.75rem 1rem; border-radius: 8px; font-size: 0.9rem; font-weight: 600; text-decoration: none; color: var(--text-primary);
    background: var(--btn-bg); border: 1px solid var(--border-color); transition: all 0.3s ease;
}
.btn:hover { background: var(--btn-hover); }
.btn.primary { background: var(--accent-color); color: #fff; border: none; }
.btn.primary:hover { background: var(--accent-hover); }

/* Tutorial Section */
.tutorial-section {
    background: var(--bg-card); backdrop-filter: blur(12px); border-radius: 16px; border: 1px solid var(--border-color);
    padding: 3rem; margin-bottom: 5rem; box-shadow: 0 4px 6px rgba(0,0,0,0.05); max-width: 800px; margin-left: auto; margin-right: auto;
}
.tutorial-header { display: flex; align-items: center; gap: 1rem; margin-bottom: 2rem; border-bottom: 1px solid var(--border-color); padding-bottom: 1rem; }
.tutorial-header i { font-size: 2rem; color: var(--accent-color); }
.tutorial-header h2 { font-size: 1.8rem; }
.tutorial-content p { color: var(--text-secondary); line-height: 1.8; margin-bottom: 1.2rem; font-size: 1.05rem; }
.tutorial-content p b { color: var(--text-primary); }
.tutorial-content code { background: rgba(0,0,0,0.2); padding: 0.2rem 0.4rem; border-radius: 4px; font-family: monospace; color: var(--accent-color); border: 1px solid var(--border-color); }

footer { margin-top: auto; border-top: 1px solid var(--border-color); padding: 2rem 0; background: var(--bg-card); backdrop-filter: blur(12px); }
.footer-content { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 1rem; color: var(--text-secondary); font-size: 0.9rem; }
.footer-links a { color: var(--text-secondary); text-decoration: none; margin-left: 1rem; transition: color 0.3s ease; }
.footer-links a:hover { color: var(--accent-color); }

/* RTL 适配微调 */
[dir="rtl"] .logo-group { flex-direction: row-reverse; }
[dir="rtl"] .nav-links { flex-direction: row-reverse; }
[dir="rtl"] .footer-links a { margin-left: 0; margin-right: 1rem; }

/* 移动端极其极窄屏幕适配 */
@media (max-width: 350px) {
    .nav-tab { font-size: 0.75rem; gap: 0.5rem; }
    .logo-img { height: 20px; }
}