/* ── Reset & Base ── */
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{background:#0f0f1a;color:#e2e8f0;font-family:system-ui,-apple-system,'Segoe UI',sans-serif;font-size:16px;line-height:1.6;min-height:100vh}
img{max-width:100%;display:block}
a{color:#8b5cf6;text-decoration:none}
a:hover{text-decoration:underline}

/* ── Typography ── */
h1,h2,h3,h4{font-weight:700;line-height:1.25;color:#fff}
h1{font-size:clamp(2rem,5vw,3.2rem)}
h2{font-size:clamp(1.5rem,3vw,2rem)}
h3{font-size:1.2rem}
p{color:#cbd5e1;line-height:1.7}
.text-muted{color:#94a3b8}
.text-accent{color:#8b5cf6}
.text-cyan{color:#06b6d4}
.text-success{color:#22c55e}
.text-error{color:#ef4444}

/* ── Layout ── */
.container{max-width:900px;margin:0 auto;padding:0 20px}
.container-wide{max-width:1100px;margin:0 auto;padding:0 20px}
.section{padding:60px 0}
.section-sm{padding:32px 0}

/* ── Navigation ── */
nav{position:sticky;top:0;z-index:100;background:rgba(15,15,26,.92);backdrop-filter:blur(12px);border-bottom:1px solid #1e1e35;padding:0 20px}
.nav-inner{max-width:1100px;margin:0 auto;display:flex;align-items:center;justify-content:space-between;height:60px}
.logo{font-size:1.15rem;font-weight:800;color:#fff;letter-spacing:-.02em}
.logo span{color:#8b5cf6}
.nav-links{display:flex;gap:4px;align-items:center;flex-wrap:wrap}
.nav-links a{padding:6px 12px;border-radius:6px;color:#94a3b8;font-size:.875rem;transition:all .15s}
.nav-links a:hover{color:#fff;background:#1a1a2e;text-decoration:none}
.nav-links a.active{color:#fff}
.nav-tool-link{background:#8b5cf6!important;color:#fff!important;padding:7px 16px!important;border-radius:20px!important}
.nav-tool-link:hover{background:#7c3aed!important}

/* ── Tools dropdown（纯 CSS，:hover + :focus-within，不依赖 app.js——很多内容页
   如 FAQ/About/隐私政策不加载 app.js，导航菜单不能靠 JS 才能用）── */
.nav-dropdown{position:relative}
.nav-dropdown-menu{position:absolute;top:100%;left:0;margin-top:4px;background:#161626;border:1px solid #2d2d4e;
  border-radius:10px;padding:6px;min-width:190px;display:none;flex-direction:column;gap:1px;
  box-shadow:0 10px 30px rgba(0,0,0,.45);z-index:200}
.nav-dropdown-menu a{padding:9px 12px;border-radius:6px;white-space:nowrap;font-size:.85rem}
.nav-dropdown:hover .nav-dropdown-menu,
.nav-dropdown:focus-within .nav-dropdown-menu{display:flex}

/* ── Buttons ── */
.btn{display:inline-flex;align-items:center;gap:8px;padding:12px 28px;border-radius:8px;font-size:1rem;font-weight:600;cursor:pointer;border:none;transition:all .15s;text-decoration:none!important;white-space:nowrap}
.btn-primary{background:#8b5cf6;color:#fff}
.btn-primary:hover{background:#7c3aed;transform:translateY(-1px)}
.btn-cyan{background:#06b6d4;color:#fff}
.btn-cyan:hover{background:#0891b2;transform:translateY(-1px)}
.btn-outline{border:1.5px solid #3b3b5c;color:#e2e8f0;background:transparent}
.btn-outline:hover{border-color:#8b5cf6;color:#8b5cf6;background:rgba(139,92,246,.06)}
.btn-sm{padding:8px 18px;font-size:.875rem}
.btn-lg{padding:16px 40px;font-size:1.1rem;border-radius:10px}

/* ── Hero ── */
.hero{text-align:center;padding:72px 20px 48px}
.hero h1{margin-bottom:16px}
.hero .subtitle{font-size:1.2rem;color:#94a3b8;margin-bottom:36px;max-width:560px;margin-left:auto;margin-right:auto}
/* 原来是每个工具页 hero 区顶部的一行 "100% Free — No Signup"（.hero-badge），
   但那个 font-size 是明显写错的 clamp(2rem,5vw,3.2rem)——巨大字号，占了一大块
   hero 空间。现在挪到导航栏 logo 右边，做成小巧的一个 pill，不再单独占页面高度。 */
.nav-badge{display:inline-flex;align-items:center;gap:6px;background:#1a1a2e;border:1px solid #2d2d4e;border-radius:20px;padding:4px 12px;font-size:.7rem;color:#94a3b8;margin-left:12px;white-space:nowrap}
.nav-badge .dot{width:6px;height:6px;background:#22c55e;border-radius:50%;animation:pulse 2s infinite}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.4}}

/* ── Upload Zone ── */
.upload-wrap{max-width:640px;margin:0 auto}
.upload-zone{position:relative;border:2px dashed #3b3b5c;border-radius:16px;padding:52px 24px;text-align:center;cursor:pointer;transition:all .2s;background:transparent}
.upload-zone:hover,.upload-zone.drag{border-color:#8b5cf6;background:rgba(139,92,246,.06);box-shadow:0 0 32px rgba(139,92,246,.18)}
.upload-icon{width:52px;height:52px;color:#8b5cf6;margin:0 auto 16px}
.upload-title{font-size:1.1rem;font-weight:600;color:#fff;margin-bottom:8px}
.upload-hint{color:#64748b;font-size:.875rem}
/* 视觉隐藏但仍保留在渲染/无障碍树里——纯 display:none 在部分 Android
   Chrome/WebView 上有个已知问题：原生文件选择器选完文件后，change 事件
   不会触发（系统把选择结果回传给一个 display:none 的元素时会丢失），
   表现为"点上传框、选好文件，然后毫无反应"。所有 <input type="file">
   都该用这个类，不要再用 display:none 或者只隐藏某个 #file-input 这种
   写法（那样只盖住了首页/人声提取/音频分离共用的那个 input，其它工具页
   各自的 file input 一样会中招）。 */
.file-input-hidden{
  position:absolute;width:1px;height:1px;padding:0;margin:-1px;
  overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0;opacity:0;
}
/* 2026-08 实测：安卓 Chrome 上就算用了上面 .file-input-hidden，选择器能弹出来，
   选完文件后 change 事件依然不触发（Edge 上没事）——怀疑是 Chrome 对缩到 1x1px
   又 clip 掉的 file input 有更激进的"离屏元素"优化，事件投递不可靠。这个类专门
   给"大块可点区域"（拖拽上传框）用：不再把 input 缩到 1px 再靠 label 转发点击，
   而是让 input 保持和父元素（.upload-zone，已加 position:relative）同样大小、
   直接盖在最上面、只是透明——用户的点击/触摸直接落在真正的 input 上，不经过
   任何 label 或 JS 转发，从根源上避免"离屏太小的 file input 事件不可靠"这类问题。 */
.file-input-cover{
  position:absolute;inset:0;width:100%;height:100%;
  opacity:0;cursor:pointer;-webkit-tap-highlight-color:transparent;
}
.upload-choose-wrap{margin-top:20px}
/* 手机上（触屏、无 hover）根本没有"把文件从桌面拖进浏览器"这个操作场景，拖拽区
   那套虚线框 + 大留白 + 图标 + 提示文字的视觉在这没有意义，干脆退化成一个干净的
   按钮外观，只留"Choose File"这一个视觉元素——交互路径完全不变（还是同一个
   .file-input-cover 盖在 .upload-zone 上），只是不再假装自己是个拖拽区。 */
@media (hover:none) and (pointer:coarse){
  .upload-zone{
    border:none;padding:0;background:transparent;
    /* 缩到贴合按钮本身大小（display:table 是经典的"收缩到内容宽度但仍可用
       margin:auto 居中"写法），不要再撑满整行——.file-input-cover 盖住的是
       .upload-zone 的整个盒子，撑满一整行的话，安卓 Chrome 默认的点击高亮
       效果会把这一整条不可见区域画成一个突兀的大方框（实测截图可见）。
       -webkit-tap-highlight-color:transparent 双保险，彻底关掉这个默认高亮。 */
    display:table;margin-left:auto;margin-right:auto;
    -webkit-tap-highlight-color:transparent;
  }
  .upload-zone:hover,.upload-zone.drag{background:transparent;box-shadow:none}
  .upload-zone .upload-icon,
  .upload-zone .upload-title,
  .upload-zone .upload-hint{display:none}
  .upload-choose-wrap{margin-top:0}
}

/* ── Progress ── */
.progress-section{max-width:640px;margin:0 auto;text-align:center;padding:0 20px}
.progress-title{font-size:1.1rem;font-weight:600;margin-bottom:8px}
.progress-bar-wrap{background:#1a1a2e;border-radius:8px;height:8px;margin:12px 0;overflow:hidden}
.progress-bar{background:linear-gradient(90deg,#8b5cf6,#06b6d4);height:100%;width:0;transition:width .5s ease;border-radius:8px}
.progress-label{color:#64748b;font-size:.875rem;min-height:20px}

/* ── Knowledge Card ── */
.knowledge-card{background:#1a1a2e;border:1px solid #2d2d4e;border-radius:12px;padding:20px 24px;margin-top:20px;text-align:left;transition:opacity .4s ease;min-height:90px}
.knowledge-q{color:#8b5cf6;font-size:.75rem;font-weight:700;text-transform:uppercase;letter-spacing:.08em;margin-bottom:8px}
.knowledge-a{color:#cbd5e1;font-size:.95rem;line-height:1.6}

/* ── Result ── */
.result-section{max-width:640px;margin:0 auto;text-align:center;padding:0 20px}
.result-icon{font-size:2.5rem;margin-bottom:8px}
.result-title{font-size:1.4rem;font-weight:700;color:#22c55e;margin-bottom:4px}
.result-sub{color:#64748b;margin-bottom:20px}
.download-buttons{display:flex;flex-direction:column;gap:16px;align-items:center;margin-bottom:20px}
.stem-row{display:flex;flex-direction:column;align-items:center;gap:10px;width:100%}
.stem-btns{display:flex;gap:10px;flex-wrap:wrap;justify-content:center}
.download-btn{display:inline-flex;align-items:center;gap:8px;padding:14px 24px;background:#06b6d4;color:#fff;border-radius:8px;font-weight:600;font-size:.95rem;transition:all .15s;text-decoration:none!important}
.download-btn:hover{background:#0891b2;transform:translateY(-1px)}
.download-btn.vocals{background:#8b5cf6}
.download-btn.vocals:hover{background:#7c3aed}
.preview-btn{display:inline-flex;align-items:center;gap:6px;padding:14px 20px;background:none;border:2px solid #334155;color:#94a3b8;border-radius:8px;font-weight:600;font-size:.95rem;cursor:pointer;transition:all .15s}
.preview-btn:hover:not(:disabled){border-color:#8b5cf6;color:#8b5cf6}
.preview-btn:disabled{opacity:.5;cursor:default}
.stem-player{width:100%;max-width:480px;height:40px;accent-color:#8b5cf6}

/* ── Error ── */
.error-box{background:rgba(239,68,68,.08);border:1px solid rgba(239,68,68,.3);border-radius:12px;padding:24px;text-align:center;color:#f87171;max-width:640px;margin:0 auto 32px}

/* ── Cards & Grid ── */
.card{background:#1a1a2e;border:1px solid #2d2d4e;border-radius:12px;padding:28px}
.card-grid{display:grid;gap:20px}
.card-grid-2{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}
.card-grid-3{grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}
.card-grid-4{grid-template-columns:repeat(auto-fit,minmax(180px,1fr))}
.card h3{margin-bottom:10px}
.card p{font-size:.9rem}

/* ── How It Works Steps ── */
.steps{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:0;counter-reset:step}
.step{position:relative;text-align:center;padding:32px 24px}
.step::before{counter-increment:step;content:counter(step);display:flex;align-items:center;justify-content:center;width:44px;height:44px;background:linear-gradient(135deg,#8b5cf6,#06b6d4);border-radius:50%;font-weight:700;font-size:1.1rem;margin:0 auto 16px;color:#fff}
.step h3{margin-bottom:8px;font-size:1rem}
.step p{font-size:.875rem;color:#64748b}
.steps-connector{display:none}

/* ── FAQ ── */
.faq-item{border-bottom:1px solid #2d2d4e;padding:20px 0}
.faq-item:last-child{border-bottom:none}
.faq-q{font-weight:600;color:#fff;cursor:pointer;display:flex;justify-content:space-between;align-items:center;gap:16px;list-style:none;padding:0}
.faq-q::after{content:'＋';color:#8b5cf6;font-size:1.2rem;flex-shrink:0;transition:transform .2s}
details[open] .faq-q::after{transform:rotate(45deg)}
.faq-a{padding-top:12px;color:#94a3b8;font-size:.95rem;line-height:1.7}

/* ── Blog ── */
.blog-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:24px}
.blog-card{background:#1a1a2e;border:1px solid #2d2d4e;border-radius:12px;overflow:hidden;transition:border-color .2s}
.blog-card:hover{border-color:#8b5cf6;text-decoration:none}
.blog-card-body{padding:24px}
.blog-tag{display:inline-block;background:rgba(139,92,246,.15);color:#8b5cf6;border-radius:4px;padding:3px 8px;font-size:.75rem;font-weight:600;margin-bottom:10px}
.blog-card h3{font-size:1rem;margin-bottom:8px;color:#fff}
.blog-card p{font-size:.875rem;color:#64748b;line-height:1.5}
.blog-card-footer{display:flex;justify-content:space-between;align-items:center;margin-top:12px;font-size:.8rem;color:#475569}

/* ── Article / Blog Post ── */
.article-header{padding:60px 0 32px;text-align:center}
.article-meta{color:#64748b;font-size:.875rem;margin-bottom:20px}
.article-body{max-width:720px;margin:0 auto}
.article-body h2{font-size:1.5rem;margin:36px 0 14px;padding-top:8px;border-top:1px solid #1e1e35}
.article-body h3{font-size:1.15rem;margin:24px 0 10px}
.article-body p{margin-bottom:16px;color:#cbd5e1}
.article-body ul,.article-body ol{margin:0 0 16px 24px;color:#cbd5e1}
.article-body li{margin-bottom:6px;line-height:1.7}
/* :not(.btn) 排除按钮链接——不加这个的话 .article-body a（class+元素选择器，
   优先级 0,1,1）会压过 .btn-primary/.btn-outline 自己的 color（只有单类选择器，
   优先级 0,1,0），导致 .btn-primary 的文字被强制变成 #8b5cf6，和它自己的背景色
   完全一样，文字直接看不见——博客文章里好几个"Try Free Vocal Remover"之类的
   CTA 按钮都受影响。 */
.article-body a:not(.btn){color:#8b5cf6}
.article-body blockquote{border-left:3px solid #8b5cf6;padding:12px 20px;margin:20px 0;background:#1a1a2e;border-radius:0 8px 8px 0;color:#94a3b8;font-style:italic}
.article-body .cta-box{background:linear-gradient(135deg,rgba(139,92,246,.15),rgba(6,182,212,.1));border:1px solid #3b3b5c;border-radius:12px;padding:28px;text-align:center;margin:36px 0}

/* ── Comparison Table ── */
.compare-table{width:100%;border-collapse:collapse;margin:24px 0;font-size:.9rem}
.compare-table th{background:#1a1a2e;color:#8b5cf6;padding:12px 16px;text-align:left;font-weight:600;border-bottom:2px solid #2d2d4e}
.compare-table td{padding:12px 16px;border-bottom:1px solid #1e1e35;color:#cbd5e1;vertical-align:top}
.compare-table tr:hover td{background:rgba(255,255,255,.02)}
.check{color:#22c55e}
.cross{color:#ef4444}

/* ── Features Bar ── */
.features-bar{background:#1a1a2e;border-top:1px solid #2d2d4e;border-bottom:1px solid #2d2d4e;padding:20px 0}
.features-bar-inner{display:flex;gap:32px;justify-content:center;flex-wrap:wrap;align-items:center}
.feat-item{display:flex;align-items:center;gap:8px;font-size:.875rem;color:#94a3b8}
.feat-item .icon{color:#22c55e;font-size:1rem}

/* ── Use Cases ── */
.use-cases{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:16px;margin:24px 0}
.use-case{background:#1a1a2e;border:1px solid #2d2d4e;border-radius:10px;padding:20px;text-align:center}
.use-case .emoji{font-size:1.8rem;margin-bottom:10px}
.use-case h4{font-size:.9rem;margin-bottom:6px}
.use-case p{font-size:.8rem;color:#64748b}

/* ── Tool Tabs ── */
.tool-tabs{display:flex;gap:8px;justify-content:center;flex-wrap:wrap;margin-bottom:32px}
.tool-tab{padding:8px 18px;border-radius:20px;border:1.5px solid #3b3b5c;color:#94a3b8;font-size:.875rem;cursor:pointer;transition:all .15s;background:transparent;text-decoration:none!important}
.tool-tab:hover,.tool-tab.active{border-color:#8b5cf6;color:#8b5cf6;background:rgba(139,92,246,.08)}

/* ── Related Tools ── */
.related-tools{background:#1a1a2e;border-radius:12px;padding:28px;text-align:center;margin-top:40px}
.related-tools h3{margin-bottom:16px;color:#fff}
.related-tools-links{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.related-tools-links a{padding:8px 18px;border:1.5px solid #3b3b5c;border-radius:20px;color:#94a3b8;font-size:.875rem;transition:all .15s}
.related-tools-links a:hover{border-color:#8b5cf6;color:#8b5cf6;text-decoration:none}

/* ── Footer ── */
footer{border-top:1px solid #1e1e35;padding:48px 20px 32px;margin-top:80px}
.footer-inner{max-width:900px;margin:0 auto}
.footer-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:32px;margin-bottom:40px}
.footer-col h4{color:#fff;font-size:.875rem;margin-bottom:14px;text-transform:uppercase;letter-spacing:.06em}
.footer-col a{display:block;color:#64748b;font-size:.875rem;margin-bottom:8px;transition:color .15s}
.footer-col a:hover{color:#94a3b8;text-decoration:none}
.footer-bottom{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:12px;padding-top:24px;border-top:1px solid #1e1e35;color:#475569;font-size:.8rem}
.footer-bottom a{color:#475569}
.footer-bottom a:hover{color:#64748b;text-decoration:none}

/* ── Breadcrumb ── */
.breadcrumb{color:#475569;font-size:.85rem;margin-bottom:24px}
.breadcrumb a{color:#64748b}
.breadcrumb a:hover{color:#94a3b8}
.breadcrumb span{margin:0 6px}

/* ── Alert / Notice ── */
.alert{border-radius:8px;padding:14px 18px;margin-bottom:20px;font-size:.9rem}
.alert-info{background:rgba(6,182,212,.08);border:1px solid rgba(6,182,212,.25);color:#38bdf8}
/* 低调说明文字：不用醒目的有色提示框，纯灰色小字，用于辅助性说明而非需要用户
   特别留意的警告（对照 alert-info 的醒目青色框，二者用途不同，按需选用）。 */
.hint-text{color:#64748b;font-size:.8rem;line-height:1.5}

/* ── Review Widget ── */
.review-widget{background:#1a1a2e;border:1px solid #2d2d4e;border-radius:12px;padding:24px;margin-top:24px;text-align:center}
.review-title{font-size:.95rem;font-weight:600;color:#94a3b8;margin-bottom:12px}
.review-hint{font-weight:400;color:#64748b;font-size:.85rem}
.star-row{display:flex;gap:6px;justify-content:center;margin-bottom:4px}
.star-btn{background:none;border:none;font-size:2.2rem;line-height:1;cursor:pointer;color:#2d2d4e;transition:color .1s;padding:2px}
.star-btn.active{color:#f59e0b}
.star-btn.hov{color:#fbbf24}
.review-saved{margin-top:8px;color:#22c55e;font-weight:600;font-size:.9rem}
.review-comment-wrap{margin-top:16px}
#review-comment{width:100%;background:#0f0f1a;border:1px solid #2d2d4e;border-radius:8px;color:#e2e8f0;font-size:.9rem;font-family:inherit;padding:10px 12px;resize:vertical;min-height:72px;transition:border-color .15s}
#review-comment:focus{outline:none;border-color:#8b5cf6}
.review-comment-footer{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:4px 0 0}
.review-char-count{font-size:.75rem;color:#475569}

/* ── Responsive ── */
@media(max-width:640px){
  .hero{padding:48px 16px 32px}
  .section{padding:40px 0}
  .btn-lg{padding:14px 28px;font-size:1rem}
  .nav-links .hide-mobile{display:none}
  .nav-badge{display:none}
  .footer-bottom{flex-direction:column;text-align:center}
}