/* ===== SimpleTab 宣传页 · 基础（沉浸式亮色） ===== */
:root{
  --accent:#39C5BB;
  --accent-on:#073b36;
  --accent-text:#0f8f87;
  --bg-0:#f6f8fc;
  --text:#0d2b2e;
  --text-dim:rgba(13,43,46,.64);
  --text-faint:rgba(13,43,46,.44);
  --glass:rgba(255,255,255,.72);
  --glass-strong:rgba(255,255,255,.94);
  --glass-border:rgba(13,43,46,.1);
  --font:"Segoe UI","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --ease:cubic-bezier(.22,.61,.36,1);
  --shadow-sm:0 8px 22px rgba(13,43,46,.07);
  --shadow-md:0 18px 44px rgba(13,43,46,.1);
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:var(--font);color:var(--text);background:var(--bg-0);line-height:1.6;-webkit-font-smoothing:antialiased;overflow-x:hidden}
a{color:inherit;text-decoration:none}
img{max-width:100%}

/* ===== 按钮（四边圆角） ===== */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:.5rem;height:44px;padding:0 1.5rem;border-radius:12px;
  font-size:14.5px;font-weight:600;letter-spacing:.02em;position:relative;overflow:hidden;
  transition:transform .25s var(--ease),box-shadow .3s var(--ease),background .3s;cursor:pointer;white-space:nowrap}
.btn-lg{height:54px;padding:0 2.4rem;font-size:16.5px}
.btn-primary{background:linear-gradient(135deg,#4fd6cb,#22a39a);color:#fff;box-shadow:0 12px 30px rgba(57,197,187,.32)}
.btn-primary::after{content:"";position:absolute;inset:0;background:radial-gradient(120% 140% at 50% -30%,rgba(255,255,255,.4),transparent 55%);opacity:0;transition:opacity .35s}
.btn-primary:hover{transform:translateY(-3px);box-shadow:0 18px 42px rgba(57,197,187,.5)}
.btn-primary:hover::after{opacity:1}
.btn-primary:active{transform:translateY(-1px) scale(.985)}
.btn-ghost{background:var(--glass);border:1px solid var(--glass-border);color:var(--text);backdrop-filter:blur(8px);box-shadow:var(--shadow-sm)}
.btn-ghost:hover{background:var(--glass-strong);transform:translateY(-3px);box-shadow:var(--shadow-md)}
.btn-ghost:active{transform:translateY(-1px) scale(.985)}

/* ===== 进入遮罩 ===== */
.loader{position:fixed;inset:0;z-index:999;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:22px;
  background:linear-gradient(162deg,#f6f8fc 0%,#eef4f8 100%);pointer-events:auto;
  transition:opacity .8s var(--ease),visibility .8s var(--ease)}
.loader img{width:96px;height:96px;border-radius:16px;box-shadow:0 16px 40px rgba(57,197,187,.35);
  opacity:0;animation:pop .7s var(--ease) .1s forwards}
.loader .lt{font-size:28px;font-weight:700;color:#143038;letter-spacing:.02em;opacity:0;
  animation:rise .7s var(--ease) .28s forwards}
.loader .loader-btn{opacity:0;margin-top:14px;border:none;background:none;box-shadow:none;cursor:pointer;
  font-size:19px;font-weight:600;color:#143038;letter-spacing:.02em;padding:13px 6px;
  display:inline-flex;align-items:center;gap:11px;
  animation:rise .7s var(--ease) .5s forwards;transition:color .25s var(--ease)}
.loader .loader-btn::after{content:"→";color:var(--accent-text);font-size:23px;transition:transform .25s var(--ease)}
.loader .loader-btn:hover{color:var(--accent-text)}
.loader .loader-btn:hover::after{transform:translateX(4px)}
.loader.hide{opacity:0;visibility:hidden;pointer-events:none}
@keyframes pop{from{opacity:0;transform:scale(.72)}to{opacity:1;transform:scale(1)}}

/* ===== Hero：沉浸式首屏 ===== */
.hero{position:relative;min-height:100svh;display:flex;flex-direction:column;align-items:center;justify-content:center;
  padding:110px 24px 56px;overflow:hidden;text-align:center;
  background:
    radial-gradient(52% 46% at 18% 12%, rgba(255,255,255,.95), transparent 66%),
    radial-gradient(48% 42% at 84% 18%, rgba(150,214,222,.5), transparent 66%),
    radial-gradient(55% 50% at 48% 96%, rgba(168,176,236,.4), transparent 66%),
    radial-gradient(30% 28% at 66% 52%, rgba(244,172,196,.25), transparent 70%),
    linear-gradient(162deg,#f6f8fc 0%,#e4eef4 45%,#d9e4ef 100%)}
.hero::before,.hero::after{content:"";position:absolute;border-radius:50%;filter:blur(70px);pointer-events:none;z-index:0}
.hero::before{width:560px;height:560px;left:-140px;top:-120px;background:rgba(140,214,224,.4);animation:drift1 22s var(--ease) infinite alternate}
.hero::after{width:520px;height:520px;right:-120px;bottom:-140px;background:rgba(190,196,244,.45);animation:drift2 26s var(--ease) infinite alternate}
@keyframes drift1{to{transform:translate(90px,60px) scale(1.12)}}
@keyframes drift2{to{transform:translate(-80px,-50px) scale(1.08)}}

.hero .brand{position:absolute;top:24px;left:clamp(16px,4vw,48px);z-index:2;display:flex;align-items:center;gap:10px;
  font-size:17px;font-weight:600;letter-spacing:.01em;color:var(--text);opacity:0}
body.loaded .hero .brand{animation:fadeIn .8s var(--ease) .1s forwards}
.hero .brand .logo{width:32px;height:32px;border-radius:8px;object-fit:cover;box-shadow:0 4px 12px rgba(57,197,187,.3)}
@keyframes fadeIn{to{opacity:1}}

.hero-inner{position:relative;z-index:1;max-width:920px}
.hero-inner>*{opacity:0;transform:translateY(26px)}
body.loaded .hero-inner>*{animation:rise .9s var(--ease) forwards}
body.loaded .hero-inner h1{animation-delay:.12s}
body.loaded .hero-inner .sub{animation-delay:.26s}
body.loaded .hero-inner .cta{animation-delay:.4s}
@keyframes rise{to{opacity:1;transform:none}}
.hero h1{font-size:clamp(2.3rem,5.6vw,3.6rem);font-weight:700;line-height:1.28;letter-spacing:-.02em;margin:0 0 1.1rem;color:#143038}
.hero .sub{max-width:560px;margin:0 auto 2.2rem;color:var(--text-dim);font-size:17px;letter-spacing:.02em}
.hero .cta{display:flex;gap:16px;justify-content:center;align-items:center;flex-wrap:wrap}

.hero-visual{position:relative;z-index:1;width:min(860px,92%);margin-top:48px;aspect-ratio:11/6;
  display:grid;place-items:center;
  opacity:0;transform:translateY(30px)}
body.loaded .hero-visual{animation:rise 1s var(--ease) .5s forwards}
.hero-visual img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;z-index:2;border-radius:20px}
.hero-visual img.miss{display:none}

.scroll-hint{position:absolute;right:clamp(18px,3vw,40px);top:50%;transform:translateY(-50%);z-index:1;
  font-size:13px;font-weight:600;color:var(--text-dim);letter-spacing:.2em;display:flex;flex-direction:column;align-items:center;gap:8px;
  opacity:1;transition:opacity .5s}
body.loaded .scroll-hint{animation:fadeIn 1s var(--ease) .9s backwards}
.scroll-hint::after{content:"";width:1px;height:30px;background:linear-gradient(180deg,var(--text-dim),transparent);animation:drip 1.8s var(--ease) infinite}
@keyframes drip{0%{transform:scaleY(0);transform-origin:top}45%{transform:scaleY(1);transform-origin:top}55%{transform:scaleY(1);transform-origin:bottom}100%{transform:scaleY(0);transform-origin:bottom}}
.ph-label{font-size:14px;color:var(--text-faint);letter-spacing:.06em}

/* ===== 通用 section ===== */
main section{max-width:1100px;margin:0 auto;padding:100px 24px}
.sec-head{text-align:center;margin-bottom:54px}
.sec-head h2{font-size:clamp(1.6rem,3.4vw,2.2rem);font-weight:700;letter-spacing:-.01em;margin-bottom:.7rem;color:#143038}
/* 渐变标题：不支持 background-clip 的环境自动回落为纯色 */
@supports (background-clip:text){
  .sec-head h2{background:linear-gradient(115deg,#143038 8%,#0f8f87 55%,#4aa8f0);-webkit-background-clip:text;background-clip:text;color:transparent;-webkit-text-fill-color:transparent}
}
.sec-head p{color:var(--text-faint);font-size:15px}
.sec-head::after{content:"";display:block;width:44px;height:3px;border-radius:3px;margin:16px auto 0;
  background:linear-gradient(90deg,#4fd6cb,#4aa8f0)}

/* ===== 滚动渐显（IntersectionObserver 触发 .in） ===== */
.reveal,.reveal-media,.reveal-desc{opacity:0;will-change:opacity,transform;
  transition:opacity .9s var(--ease),transform .9s var(--ease)}
.reveal{transform:translateY(32px)}
.reveal-media{transform:translateY(40px) scale(.95)}
.reveal-desc{transform:translateY(32px)}
.feature:nth-child(odd) .reveal-media{transform:translate(-24px,40px) scale(.95)}
.feature:nth-child(odd) .reveal-desc{transform:translate(24px,32px)}
.feature:nth-child(even) .reveal-media{transform:translate(24px,40px) scale(.95)}
.feature:nth-child(even) .reveal-desc{transform:translate(-24px,32px)}
.reveal.in,.reveal-media.in,.reveal-desc.in{opacity:1 !important;transform:none !important}

/* ===== 功能总览（浅色纯色容器 + 子卡片） ===== */
.overview{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-bottom:84px;padding:20px;
  background:rgba(255,255,255,.55);border:1px solid var(--glass-border);border-radius:24px;box-shadow:var(--shadow-sm)}
.ov-card{background:var(--glass);border:1px solid var(--glass-border);border-radius:16px;padding:1.45rem 1.35rem;backdrop-filter:blur(8px);
  transition:transform .3s var(--ease),box-shadow .35s var(--ease),border-color .35s}
.ov-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-md);border-color:rgba(57,197,187,.4)}
.ov-head{display:flex;align-items:center;gap:8px;margin-bottom:.5rem}
.ov-ico{width:19px;height:19px;flex:none;color:var(--accent-text)}
.ov-card h4{font-size:15.5px;font-weight:600;color:#143038;margin:0}
.ov-card p{font-size:13px;color:var(--text-dim);line-height:1.7}

/* ===== 功能：左右交替 ===== */
.feature{display:flex;align-items:center;gap:clamp(24px,5vw,64px);margin-bottom:84px}
.feature:last-child{margin-bottom:0}
.feature .f-media{flex:1;aspect-ratio:16/10;display:grid;place-items:center;position:relative}
.feature .f-media img{position:absolute;inset:0;width:100%;height:100%;object-fit:contain;z-index:2}
.feature .f-media img.miss{display:none}
.feature .f-media img.rounded{border-radius:20px}
.ph-label{position:relative;z-index:1}
.feature .f-desc{flex:1}
.feature .f-desc h3{font-size:clamp(1.3rem,2.6vw,1.7rem);font-weight:700;margin-bottom:.85rem;color:#143038;letter-spacing:-.01em}
.feature .f-desc p{font-size:15.5px;color:var(--text-dim);line-height:1.9}
.feature:nth-child(even){flex-direction:row-reverse}

/* ===== 安装渠道 ===== */
.channels{max-width:none;margin:0;padding:100px clamp(24px,4vw,48px);
  background:#edf3f5;border-top:1px solid rgba(13,43,46,.06);border-bottom:1px solid rgba(13,43,46,.06)}
.channels .sec-head,.channels .channel-grid{max-width:1000px;margin-left:auto;margin-right:auto}
.channel-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px}
.channel{display:flex;align-items:flex-start;gap:18px;padding:1.7rem 1.6rem;border-radius:20px;position:relative;overflow:hidden;
  background:var(--glass);border:1px solid var(--glass-border);backdrop-filter:blur(8px);box-shadow:var(--shadow-sm);
  transition:transform .3s var(--ease),box-shadow .35s var(--ease),border-color .35s}
.channel::before{content:"";position:absolute;top:0;left:0;right:0;height:1px;
  background:linear-gradient(90deg,transparent,rgba(255,255,255,.95),transparent)}
.channel:hover{transform:translateY(-5px);box-shadow:0 22px 48px rgba(13,43,46,.14);border-color:rgba(57,197,187,.5)}
.channel:nth-child(2){transition-delay:.05s}
.ch-icon{width:54px;height:54px;flex:none;border-radius:15px;display:grid;place-items:center;transition:transform .35s var(--ease);
  background:linear-gradient(135deg,rgba(57,197,187,.2),rgba(57,197,187,.06));border:1px solid rgba(57,197,187,.3)}
.ch-icon svg{width:30px;height:30px}
.ch-icon svg[stroke]{width:26px;height:26px;color:var(--accent-text)}
.channel:hover .ch-icon{transform:scale(1.08) rotate(-4deg)}
.ch-body h3{font-size:17px;font-weight:600;margin-bottom:.3rem;color:#143038}
.ch-body p{font-size:13.5px;color:var(--text-dim);margin-bottom:.75rem}
.ch-cta{display:inline-flex;align-items:center;gap:4px;font-size:14px;font-weight:600;color:var(--accent-text);transition:gap .25s var(--ease)}
.channel:hover .ch-cta{gap:9px}

/* ===== 悬浮一键到顶 ===== */
.to-top{position:fixed;right:26px;bottom:26px;z-index:900;width:46px;height:46px;border-radius:50%;
  display:grid;place-items:center;color:#fff;background:linear-gradient(135deg,#4fd6cb,#1d8f86);border:none;cursor:pointer;
  box-shadow:0 10px 26px rgba(57,197,187,.4);
  opacity:0;visibility:hidden;transform:translateY(10px);
  transition:opacity .3s var(--ease),transform .3s var(--ease),visibility .3s}
.to-top.show{opacity:1;visibility:visible;transform:none}
.to-top:hover{transform:translateY(-3px)}
.to-top svg{width:20px;height:20px}

/* ===== 页脚 ===== */
footer{padding:48px 24px;text-align:center;border-top:1px solid rgba(13,43,46,.08);color:var(--text-dim);font-size:14px;background:rgba(255,255,255,.5)}
footer a{color:var(--accent-text)}
footer .small{font-size:12.5px;color:var(--text-faint);margin-top:.3rem}
.author-link{background:none;border:none;padding:0;margin:0;font-size:inherit;font-family:inherit;color:var(--accent-text);cursor:pointer;text-decoration:underline;text-underline-offset:3px}
.author-link:hover{opacity:.75}

/* ===== 关于作者弹窗 ===== */
.modal-mask{position:fixed;inset:0;z-index:1200;display:flex;align-items:center;justify-content:center;
  background:rgba(13,43,46,.35);backdrop-filter:blur(6px);
  opacity:0;transition:opacity .3s var(--ease)}
.modal-mask[hidden]{display:none}
.modal-mask.show{opacity:1}
.modal-box{width:min(480px,92vw);border-radius:20px;padding:26px 28px;background:#fff;
  box-shadow:0 30px 70px rgba(13,43,46,.2);transform:translateY(16px) scale(.97);
  transition:transform .3s var(--ease)}
.modal-mask.show .modal-box{transform:none}
.mb-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px}
.mb-title{font-size:18px;font-weight:700;color:#143038}
.mb-close{width:30px;height:30px;border-radius:9px;display:grid;place-items:center;color:rgba(13,43,46,.5);background:none;border:none;cursor:pointer}
.mb-close:hover{background:rgba(13,43,46,.06);color:#143038}
.mb-body h4{font-size:15px;font-weight:600;color:var(--accent-text);margin-bottom:10px}
.mb-body p{font-size:14.5px;color:var(--text-dim);line-height:1.9}
.mb-foot{display:flex;justify-content:flex-end;margin-top:22px}

/* ===== 响应式 ===== */
@media (max-width:860px){
  .scroll-hint{display:none}
  .feature{flex-direction:column !important;gap:24px}
  .feature:nth-child(odd) .reveal-media,.feature:nth-child(odd) .reveal-desc,
  .feature:nth-child(even) .reveal-media,.feature:nth-child(even) .reveal-desc{transform:translateY(36px) scale(.95)}
  .overview{grid-template-columns:repeat(2,1fr)}
  .channel-grid{grid-template-columns:1fr}
  .hero{padding-top:120px}
}

/* ===== 动效偏好：禁用动画但保证内容可见 ===== */
@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{animation-duration:.01ms !important;animation-iteration-count:1 !important;transition-duration:.01ms !important;scroll-behavior:auto !important}
  .loader{display:none}
  .hero .brand,.hero-inner>*,.hero-visual,.scroll-hint{opacity:1 !important;transform:none !important}
  .reveal,.reveal-media,.reveal-desc{opacity:1 !important;transform:none !important}
}