/**
 * 星辰 AI  - 赛博朋克主样式
 * Cyberpunk: 霓虹光效 + 暗黑底色 + 扫描线 + 故障文字 + 脉冲边框
 */

/* ========================================
   1. CSS 变量 — 赛博朋克色系
   ======================================== */

:root {
    --bg-color: #0a0a0f;
    --bg-secondary: #0d0d1a;
    --text-color: #e0e0e8;
    --text-secondary: #7a7a8e;
    --sidebar-bg: rgba(10,12,25,0.92);
    --sidebar-hover: rgba(0,255,245,0.06);
    --code-bg: #05050a;
    --code-text: #00fff5;
    --border-color: rgba(0,255,245,0.12);
    --highlight-bg: rgba(240,225,48,0.25);
    --link-color: #00fff5;
    --link-hover: #ff2d95;
    --header-bg: rgba(8,8,18,0.95);
    --card-bg: rgba(10,15,30,0.85);
    --card-shadow: 0 0 20px rgba(0,255,245,0.05), 0 2px 8px rgba(0,0,0,0.4);
    --card-shadow-hover: 0 0 40px rgba(0,255,245,0.15), 0 8px 32px rgba(0,0,0,0.5);
    --success-color: #00ff88;
    --warning-color: #f0e130;
    --danger-color: #ff2d95;
    --info-color: #00d4ff;
    --neon-cyan: #00fff5;
    --neon-pink: #ff2d95;
    --neon-purple: #b537f2;
    --neon-yellow: #f0e130;
    --neon-blue: #00d4ff;
    --accent-gradient: linear-gradient(135deg, #00fff5 0%, #b537f2 50%, #ff2d95 100%);
    --glow-cyan: 0 0 10px rgba(0,255,245,0.4), 0 0 40px rgba(0,255,245,0.1);
    --glow-pink: 0 0 10px rgba(255,45,149,0.4), 0 0 40px rgba(255,45,149,0.1);
    --glass-bg: rgba(10,15,30,0.7);
    --glass-border: rgba(0,255,245,0.15);

    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;
    --spacing-3xl: 64px;

    --sidebar-width: 280px;
    --header-height: 70px;
    --content-max-width: 1100px;
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 12px;
}

/* 浅色主题 — 日间赛博 */
[data-theme="light"] {
    --bg-color: #e8e8f0;
    --bg-secondary: #d8d8e5;
    --text-color: #0a0a1a;
    --text-secondary: #4a4a5e;
    --sidebar-bg: rgba(220,220,235,0.95);
    --sidebar-hover: rgba(0,100,100,0.06);
    --code-bg: #1a1a2e;
    --code-text: #00ddd5;
    --border-color: rgba(0,120,120,0.2);
    --link-color: #006e8a;
    --link-hover: #aa0055;
    --header-bg: rgba(15,15,30,0.97);
    --card-bg: rgba(255,255,255,0.88);
    --card-shadow: 0 2px 12px rgba(0,0,0,0.08);
    --card-shadow-hover: 0 8px 32px rgba(0,120,120,0.15);
    --glass-bg: rgba(255,255,255,0.8);
    --glass-border: rgba(0,120,120,0.2);
    --neon-cyan: #007a8a;
    --neon-pink: #b8004e;
    --neon-purple: #7b22b0;
    --neon-yellow: #a89800;
    --neon-blue: #0080aa;
    --success-color: #008844;
    --warning-color: #a89800;
    --danger-color: #b8004e;
    --info-color: #0080aa;
    --glow-cyan: 0 0 8px rgba(0,122,138,0.25), 0 0 20px rgba(0,122,138,0.08);
    --glow-pink: 0 0 8px rgba(184,0,78,0.25), 0 0 20px rgba(184,0,78,0.08);
}

/* ========================================
   2. 关键帧动画
   ======================================== */

@keyframes scanline {
    0% { transform: translateY(-100vh); }
    100% { transform: translateY(100vh); }
}

@keyframes neonPulse {
    0%, 100% { border-color: rgba(0,255,245,0.3); box-shadow: 0 0 8px rgba(0,255,245,0.1); }
    50% { border-color: rgba(0,255,245,0.6); box-shadow: 0 0 20px rgba(0,255,245,0.2); }
}

@keyframes neonPulsePink {
    0%, 100% { border-color: rgba(255,45,149,0.3); }
    50% { border-color: rgba(255,45,149,0.6); }
}

@keyframes glitch {
    0%, 100% { text-shadow: 2px 0 #ff2d95, -2px 0 #00fff5; transform: translate(0); }
    20% { text-shadow: -3px 0 #ff2d95, 3px 0 #00fff5; transform: translate(2px, -1px); }
    40% { text-shadow: 3px 0 #ff2d95, -3px 0 #00fff5; transform: translate(-2px, 1px); }
    60% { text-shadow: -1px 0 #ff2d95, 1px 0 #00fff5; transform: translate(1px, 0); }
    80% { text-shadow: 2px 0 #ff2d95, -2px 0 #00fff5; transform: translate(-1px, -1px); }
}

@keyframes glitchSubtle {
    0%, 92%, 100% { opacity: 1; transform: translate(0); }
    93% { opacity: 0.8; transform: translate(-2px, 1px); }
    94% { opacity: 1; transform: translate(2px, -1px); }
    95% { opacity: 0.9; transform: translate(0); }
}

@keyframes borderSweep {
    0% { left: -100%; }
    100% { left: 200%; }
}

@keyframes flicker {
    0%, 19%, 21%, 23%, 25%, 54%, 56%, 100% { opacity: 1; }
    20%, 24%, 55% { opacity: 0.6; }
}

@keyframes cursorBlink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0; }
}

@keyframes headerLine {
    0% { background-position: 0% 50%; }
    100% { background-position: 200% 50%; }
}

/* ========================================
   3. 基础样式
   ======================================== */

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, Roboto, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.7;
    transition: background-color 0.4s, color 0.4s;
    position: relative;
    overflow-x: hidden;
}

/* 电路板网格背景 */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background:
        linear-gradient(rgba(0,255,245,0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0,255,245,0.03) 1px, transparent 1px);
    background-size: 60px 60px;
    pointer-events: none;
    z-index: 0;
}

/* 扫描线效果 */
body::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, transparent, rgba(0,255,245,0.15), transparent);
    animation: scanline 6s linear infinite;
    pointer-events: none;
    z-index: 9999;
}

[data-theme="light"] body::before {
    background:
        linear-gradient(rgba(0,150,150,0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0,150,150,0.04) 1px, transparent 1px);
    background-size: 60px 60px;
}

[data-theme="light"] body::after {
    background: linear-gradient(90deg, transparent, rgba(0,150,150,0.1), transparent);
}

/* 粒子画布 */
#particles {
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
}

/* 自定义滚动条 */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-color); }
::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, var(--neon-cyan), var(--neon-purple));
    border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover { background: var(--neon-cyan); }

/* 文字与链接 */
a { color: var(--link-color); text-decoration: none; transition: all 0.2s; }
a:hover { color: var(--link-hover); text-shadow: 0 0 8px rgba(255,45,149,0.4); }

code {
    background: rgba(0,255,245,0.08);
    color: var(--neon-cyan);
    padding: 3px 8px;
    border-radius: 4px;
    font-family: 'Fira Code', 'SF Mono', Consolas, monospace;
    font-size: 0.88em;
    border: 1px solid rgba(0,255,245,0.1);
}

strong { font-weight: 600; }
.tip strong, .warning strong { color: var(--danger-color); }

.hidden { display: none; }

/* ========================================
   4. 头部 & 布局
   ======================================== */

header {
    background: var(--header-bg);
    color: white;
    padding: 0 20px;
    height: var(--header-height);
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: space-between;
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0,255,245,0.15);
}

/* 头部底部霓虹线 — 动态流光 */
header::after {
    content: '';
    position: absolute;
    bottom: 0; left: 0; right: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--neon-cyan), var(--neon-purple), var(--neon-pink), var(--neon-cyan), transparent);
    background-size: 200% 100%;
    animation: headerLine 4s linear infinite;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
}

.header-title {
    font-size: 1.25rem;
    white-space: nowrap;
    font-weight: 700;
    letter-spacing: 2px;
    margin: 0;
    color: var(--neon-cyan);
    text-shadow: 0 0 10px rgba(0,255,245,0.5), 0 0 30px rgba(0,255,245,0.2);
    animation: glitchSubtle 8s ease-in-out infinite;
}

.header-center {
    flex: 1;
    display: flex;
    justify-content: center;
    padding: 0 20px;
    max-width: 600px;
    margin: 0 auto;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
}

/* 返回首页 */
.back-home {
    color: var(--neon-cyan);
    text-decoration: none;
    font-size: 13px;
    padding: 6px 14px;
    background: transparent;
    border: 1px solid rgba(0,255,245,0.25);
    border-radius: 4px;
    transition: all 0.3s;
}

.back-home:hover {
    background: rgba(0,255,245,0.08);
    border-color: var(--neon-cyan);
    box-shadow: var(--glow-cyan);
    color: var(--neon-cyan);
}

/* 主题切换 */
.theme-toggle {
    background: transparent;
    border: 1px solid rgba(0,255,245,0.25);
    color: var(--neon-cyan);
    padding: 8px 16px;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 600;
    font-size: 13px;
    transition: all 0.3s;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.theme-toggle:hover {
    background: rgba(0,255,245,0.1);
    border-color: var(--neon-cyan);
    box-shadow: var(--glow-cyan);
}

.menu-toggle {
    display: none;
    background: transparent;
    border: 1px solid rgba(0,255,245,0.25);
    color: var(--neon-cyan);
    padding: 8px 10px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 18px;
}

/* 容器 */
.container {
    display: flex;
    margin-top: var(--header-height);
    min-height: calc(100vh - var(--header-height));
    position: relative;
    z-index: 1;
}

/* ========================================
   5. 侧边栏
   ======================================== */

.sidebar {
    width: var(--sidebar-width);
    background: var(--sidebar-bg);
    backdrop-filter: blur(20px);
    border-right: 1px solid var(--border-color);
    padding: 20px 0;
    position: fixed;
    top: var(--header-height);
    bottom: 0;
    overflow-y: auto;
    z-index: 100;
    transition: transform 0.3s;
}

.sidebar::-webkit-scrollbar { width: 3px; }
.sidebar::-webkit-scrollbar-thumb { background: rgba(0,255,245,0.3); border-radius: 3px; }

.nav-item { padding: 0; }

.nav-item a {
    display: block;
    padding: 10px 20px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 13px;
    transition: all 0.2s;
    border-left: 2px solid transparent;
    letter-spacing: 0.5px;
}

.nav-item a:hover {
    color: var(--neon-cyan);
    background: var(--sidebar-hover);
    border-left-color: var(--neon-cyan);
    text-shadow: 0 0 8px rgba(0,255,245,0.3);
}

.nav-item.active a {
    color: var(--neon-cyan);
    background: rgba(0,255,245,0.06);
    border-left-color: var(--neon-cyan);
    font-weight: 600;
    text-shadow: 0 0 8px rgba(0,255,245,0.3);
}

.nav-parent { cursor: pointer; }
.nav-toggle { display: inline-block; margin-right: 6px; font-size: 10px; transition: transform 0.2s; color: var(--neon-cyan); }
.nav-parent.expanded .nav-toggle { transform: rotate(90deg); }

.nav-children, .nav-subchildren { display: none; padding-left: 12px; }
.nav-children.show, .nav-subchildren.show { display: block; }

.nav-child a, .nav-subchild a {
    display: block;
    padding: 7px 20px 7px 32px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 12px;
    transition: all 0.2s;
    border-left: 1px solid transparent;
}

.nav-child a:hover, .nav-subchild a:hover { color: var(--neon-cyan); background: var(--sidebar-hover); }
.nav-child.active a, .nav-subchild.active a { color: var(--neon-cyan); font-weight: 600; border-left-color: var(--neon-cyan); }

.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.7);
    backdrop-filter: blur(4px);
    z-index: 99;
}
.sidebar-overlay.show { display: block; }

/* ========================================
   6. 主内容区 & 章节
   ======================================== */

.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: var(--spacing-xl) var(--spacing-2xl);
    max-width: var(--content-max-width);
    position: relative;
    z-index: 1;
}

.main-content-full {
    max-width: var(--content-max-width);
    margin: 0 auto;
    padding: 90px 20px 40px;
    position: relative;
    z-index: 1;
}

.section {
    margin-bottom: var(--spacing-3xl);
    scroll-margin-top: calc(var(--header-height) + 20px);
}

.section h2 {
    font-size: 1.5em;
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
    color: var(--neon-cyan);
    text-shadow: 0 0 15px rgba(0,255,245,0.3);
    letter-spacing: 1px;
    position: relative;
}

/* h2 底部霓虹线 */
.section h2::after {
    content: '';
    position: absolute;
    bottom: -1px; left: 0;
    width: 60px; height: 2px;
    background: var(--neon-cyan);
    box-shadow: 0 0 10px var(--neon-cyan);
}

.section h3 {
    font-size: 1.15em;
    margin: var(--spacing-xl) 0 var(--spacing-md);
    color: var(--neon-purple);
    scroll-margin-top: calc(var(--header-height) + 20px);
    text-shadow: 0 0 8px rgba(181,55,242,0.2);
}

.section h4 {
    font-size: 1.05em;
    margin: var(--spacing-lg) 0 var(--spacing-sm);
    color: var(--text-color);
}

.section p { margin-bottom: var(--spacing-md); text-indent: 0; }
.section ul, .section ol { margin: var(--spacing-md) 0; padding-left: 2em; }
.section li { margin-bottom: var(--spacing-sm); }

/* ========================================
   7. 组件样式
   ======================================== */

/* 代码块 — 终端风格 */
.code-block {
    position: relative;
    margin: var(--spacing-md) 0;
    border-radius: var(--border-radius-md);
    overflow: hidden;
    border: 1px solid rgba(0,255,245,0.15);
    border-left: 3px solid var(--neon-cyan);
}

.code-block pre {
    background: var(--code-bg);
    color: var(--code-text);
    padding: 16px 20px;
    overflow-x: auto;
    font-family: 'Fira Code', 'SF Mono', Consolas, monospace;
    font-size: 13px;
    line-height: 1.6;
    margin: 0;
    text-shadow: 0 0 6px rgba(0,255,245,0.15);
}

.copy-btn {
    position: absolute;
    top: 8px; right: 8px;
    background: rgba(0,255,245,0.08);
    border: 1px solid rgba(0,255,245,0.3);
    color: var(--neon-cyan);
    padding: 5px 12px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 11px;
    transition: all 0.2s;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.copy-btn:hover {
    background: rgba(0,255,245,0.15);
    box-shadow: var(--glow-cyan);
}

.copy-btn.copied {
    background: rgba(0,255,136,0.15);
    border-color: var(--success-color);
    color: var(--success-color);
}

/* 提示框 */
.tip {
    background: rgba(0,255,136,0.04);
    border: 1px solid rgba(0,255,136,0.2);
    border-left: 3px solid var(--success-color);
    border-radius: var(--border-radius-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    margin: var(--spacing-md) 0;
}

.warning {
    background: rgba(240,225,48,0.04);
    border: 1px solid rgba(240,225,48,0.2);
    border-left: 3px solid var(--neon-yellow);
    border-radius: var(--border-radius-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    margin: var(--spacing-md) 0;
}

/* 图片容器 */
.img-container { margin: var(--spacing-md) 0; text-align: center; }

.img-container img {
    max-width: 100%;
    border-radius: var(--border-radius-md);
    border: 1px solid var(--border-color);
    box-shadow: 0 0 20px rgba(0,0,0,0.3);
}

.img-placeholder {
    display: inline-block;
    padding: 10px 20px;
    background: rgba(0,255,245,0.04);
    border: 1px dashed rgba(0,255,245,0.25);
    border-radius: var(--border-radius-md);
    color: var(--neon-cyan);
    cursor: pointer;
    transition: all 0.3s;
    font-size: 13px;
}

.img-placeholder:hover {
    background: rgba(0,255,245,0.08);
    border-color: var(--neon-cyan);
    box-shadow: var(--glow-cyan);
}

.img-placeholder.loading { opacity: 0.5; cursor: wait; }

/* 视频链接 */
.video-link {
    display: inline-block;
    padding: 8px 20px;
    background: linear-gradient(135deg, #ff2d95, #b537f2);
    color: white !important;
    text-decoration: none;
    border-radius: 4px;
    font-weight: 600;
    transition: all 0.3s;
    text-shadow: none;
}

.video-link:hover {
    transform: translateY(-2px);
    box-shadow: var(--glow-pink);
}

/* 返回顶部 — 赛博六边形 */
.back-to-top {
    position: fixed;
    bottom: 30px; right: 30px;
    width: 48px; height: 48px;
    background: transparent;
    color: var(--neon-cyan);
    border: 2px solid var(--neon-cyan);
    border-radius: 4px;
    font-size: 20px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s;
    z-index: 999;
    animation: neonPulse 3s ease-in-out infinite;
}

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

.back-to-top:hover {
    background: rgba(0,255,245,0.1);
    box-shadow: var(--glow-cyan);
    transform: translateY(-4px);
}

/* ========================================
   8. 步骤卡片 & 工具卡片
   ======================================== */

.step-card {
    background: var(--card-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
    position: relative;
    overflow: hidden;
    box-shadow: var(--card-shadow);
    animation: neonPulse 6s ease-in-out infinite;
}

/* 卡片角落装饰 */
.step-card::before, .step-card::after {
    content: '';
    position: absolute;
    width: 20px; height: 20px;
    border-color: var(--neon-cyan);
    border-style: solid;
    border-width: 0;
    opacity: 0.4;
}

.step-card::before {
    top: 8px; left: 8px;
    border-top-width: 2px;
    border-left-width: 2px;
}

.step-card::after {
    bottom: 8px; right: 8px;
    border-bottom-width: 2px;
    border-right-width: 2px;
}

.step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px; height: 36px;
    background: transparent;
    color: var(--neon-cyan);
    border: 2px solid var(--neon-cyan);
    border-radius: 4px;
    font-weight: 700;
    font-size: 16px;
    margin-right: 12px;
    box-shadow: var(--glow-cyan);
    font-family: 'Fira Code', monospace;
}

.step-title {
    font-size: 1.2em;
    font-weight: 700;
    color: var(--text-color);
}

.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.tool-card {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    padding: var(--spacing-lg);
    transition: all 0.3s;
    position: relative;
    overflow: hidden;
}

/* 工具卡片 hover 扫光 */
.tool-card::before {
    content: '';
    position: absolute;
    top: 0; left: -100%;
    width: 50%; height: 100%;
    background: linear-gradient(90deg, transparent, rgba(0,255,245,0.05), transparent);
    transition: left 0.5s;
}

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

.tool-card:hover {
    border-color: rgba(0,255,245,0.4);
    box-shadow: 0 0 30px rgba(0,255,245,0.08);
}

.tool-card h4 { margin-bottom: var(--spacing-sm); color: var(--text-color); }
.tool-card img { max-width: 100%; border-radius: var(--border-radius-sm); margin-top: var(--spacing-sm); }

/* details/summary */
details { margin: var(--spacing-md) 0; }

details summary {
    cursor: pointer;
    color: var(--neon-cyan);
    font-weight: bold;
    margin: 8px 0;
    padding: 8px 12px;
    background: rgba(0,255,245,0.04);
    border: 1px solid rgba(0,255,245,0.1);
    border-radius: var(--border-radius-sm);
    transition: all 0.2s;
}

details summary:hover {
    background: rgba(0,255,245,0.08);
    border-color: rgba(0,255,245,0.3);
}

/* 搜索 */
.search-container { position: relative; width: 100%; max-width: 500px; }

#searchInput {
    width: 100%;
    padding: 10px 60px 10px 16px;
    border: 1px solid rgba(0,255,245,0.25);
    border-radius: 4px;
    font-size: 13px;
    background: rgba(0,255,245,0.04);
    color: var(--neon-cyan);
    transition: all 0.3s;
}

#searchInput::placeholder { color: rgba(0,255,245,0.4); }
#searchInput:focus { outline: none; border-color: var(--neon-cyan); box-shadow: var(--glow-cyan); }

.search-info {
    position: absolute;
    right: 12px; top: 50%;
    transform: translateY(-50%);
    color: var(--neon-cyan);
    font-size: 11px;
    background: rgba(0,255,245,0.1);
    padding: 3px 8px;
    border-radius: 4px;
    pointer-events: none;
}
.search-info:empty { display: none; }

.highlight { background: var(--highlight-bg); padding: 2px 4px; border-radius: 3px; }
.highlight-current { background: var(--neon-pink); color: white; padding: 2px 4px; border-radius: 3px; }

.jump-link { text-decoration: none; transition: all 0.2s; }
.jump-link:hover { text-decoration: underline; }
.jump-link strong { color: var(--danger-color); cursor: pointer; }

/* ========================================
   9. 响应式
   ======================================== */

@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
        position: fixed;
        top: var(--header-height);
        left: 0; bottom: 0;
        z-index: 200;
        box-shadow: 4px 0 30px rgba(0,0,0,0.5);
    }
    .sidebar.open { transform: translateX(0); }
    .menu-toggle { display: block; }
    .main-content { margin-left: 0; padding: var(--spacing-lg) var(--spacing-md); }
    .back-home { display: none; }
    .header-title { font-size: 1rem; }
    .header-center { display: none; }
    .section h2 { font-size: 1.2em; }
    .tool-grid { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
    .main-content { padding: var(--spacing-md) var(--spacing-sm); }
    .code-block pre { font-size: 11px; padding: 12px; }
    .step-card { padding: var(--spacing-lg); }
}