/* Karhow v19 — iOS
   浅色优先，深色跟随系统。一套字、三种按钮、大量留白。 */
:root{
  color-scheme:light;
  --ease:cubic-bezier(.25,.8,.3,1);
  --ease-spring:cubic-bezier(.34,1.56,.64,1);
  --dur-1:.12s; --dur-2:.2s; --dur-3:.28s; --dur-4:.6s;
  --bg:#F2F2F7; --card:#FFFFFF;
  --ink:#1C1C1E; --mut:#8E8E93;
  --line:#E5E5EA; --soft:#F2F2F7;
  --blue:#007AFF;
  --radius:18px;
  /* v23 设计 token：间距 / 圆角 / 字号 / 字体栈 */
  --sp-1:4px; --sp-2:8px; --sp-3:12px; --sp-4:16px; --sp-5:20px; --sp-6:24px;
  --sp-7:32px; --sp-8:40px; --sp-9:52px; --sp-10:64px; --sp-hero:76px;
  --sp-gutter:20px; --sp-card:14px; --sp-block:34px;
  --r-sm:10px; --r-md:14px; --r-lg:18px; --r-card:20px;
  --fs-cap:12px; --fs-sm:14px; --fs-md:16px; --fs-lg:19px; --fs-xl:24px; --fs-2xl:34px;
  --fs-hero:clamp(38px,5.2vw + 12px,56px);
  --fs-h1:clamp(28px,2.6vw + 18px,34px);
  --fs-title:clamp(22px,3.4vw,28px);
  --w-content:720px;
  --font-sans:-apple-system,BlinkMacSystemFont,"SF Pro Text","Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,"Noto Sans SC",sans-serif;
  --font-serif:"Songti SC","Source Han Serif SC","Noto Serif SC",Georgia,"SimSun",serif;
  --shadow:0 1px 2px rgba(0,0,0,.05),0 8px 30px rgba(0,0,0,.06);
  --shadow-lg:0 20px 60px rgba(0,0,0,.2);
}
*{box-sizing:border-box;margin:0;padding:0}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;font-size:16px}
body{background:var(--bg);color:var(--ink);
  font-family:var(--font-sans);
  line-height:1.7;letter-spacing:0;
  text-spacing-trim:space-all;text-autospace:normal;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;min-height:100vh}
body.modal-open{overflow:hidden}
::selection{background:#B3D7FF}
h1,h2,h3{letter-spacing:-.01em;line-height:1.2;font-weight:700}
h1,h2,h3,.essay-title,.page-head h1{text-wrap:balance}
a{color:var(--blue);text-decoration:none}
a:hover{text-decoration:underline}
.essay-body a,.prose a{text-decoration:underline;text-underline-offset:.18em;text-decoration-thickness:1px;text-decoration-color:color-mix(in srgb,var(--blue) 45%,transparent)}
img{max-width:100%}
.wrap{width:100%;max-width:var(--w-content);margin:0 auto;padding:0 var(--sp-gutter)}
.serif{font-family:var(--font-serif)}

/* ---------- 顶栏 ---------- */
.nav{position:sticky;top:0;z-index:100;background:rgba(242,242,247,.8);
  backdrop-filter:blur(14px) saturate(1.5);-webkit-backdrop-filter:blur(14px) saturate(1.5);
  border-bottom:1px solid transparent;transition:border-color .25s var(--ease);
  view-transition-name:site-nav}
.nav.scrolled{border-bottom-color:var(--line)}
.nav-inner{max-width:var(--w-content);margin:0 auto;padding:12px var(--sp-gutter);display:flex;align-items:center;gap:18px}
.brand{display:inline-flex;align-items:center;gap:8px;color:var(--ink);font-weight:750;
  font-size:16px;letter-spacing:-.02em;white-space:nowrap}
.brand:hover{text-decoration:none}
.brand svg{width:24px;height:24px;border-radius:6px;display:block}
.tabs{display:flex;gap:2px;align-items:center}
.tabs a{color:var(--mut);font-size:14px;font-weight:500;padding:7px 11px;border-radius:9px}
.tabs a:hover{color:var(--ink);text-decoration:none;background:rgba(120,120,128,.1)}
.tabs a.active{color:var(--ink);font-weight:700}
.nav-right{margin-left:auto;display:flex;align-items:center;gap:10px}
.btn-login{background:var(--ink);color:#fff;border:0;border-radius:999px;padding:8px 18px;
  min-height:34px;font-size:13px;font-weight:700;cursor:pointer;font-family:inherit;white-space:nowrap;
  text-decoration:none;transition:opacity var(--dur-2) var(--ease),transform var(--dur-1) var(--ease)}
.btn-login:hover{opacity:.85;text-decoration:none}
.btn-login:active{transform:scale(.96)}
.nav-toggle{display:none;background:none;border:0;color:var(--ink);font-size:20px;cursor:pointer;
  min-width:40px;min-height:40px;border-radius:10px;font-family:inherit}
.usermenu{position:relative}
.user-btn{display:flex;align-items:center;gap:8px;background:var(--card);border:1px solid var(--line);
  border-radius:999px;padding:4px 12px 4px 4px;cursor:pointer;color:var(--ink);
  font-size:13px;font-weight:600;font-family:inherit}
.caret{color:var(--mut);font-size:11px}
.dropdown{position:absolute;right:0;top:calc(100% + 9px);min-width:180px;background:var(--card);
  border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow-lg);padding:6px;
  display:flex;flex-direction:column;z-index:120}
.dropdown .mail{margin:2px 0 4px;padding:7px 12px 6px;font-size:11px;color:var(--mut);
  border-bottom:1px solid var(--line);word-break:break-all}
.dropdown button{background:transparent;border:0;color:var(--ink);text-align:left;
  font-family:inherit;font-size:14px;font-weight:500;border-radius:9px;padding:9px 12px;cursor:pointer}
.dropdown button:hover{background:var(--soft)}
.nav-drawer{display:none}

/* ---------- 页头 ---------- */
.page-head{padding:var(--sp-9) 0 6px}
.page-head h1{font-size:var(--fs-h1);margin:0 0 8px}
.page-head .sub{margin:0;color:var(--mut);font-size:15px}
.sec{padding:var(--sp-block) 0 0}
.sec-head{display:flex;align-items:baseline;justify-content:space-between;gap:12px;
  margin-bottom:14px}
.sec-head h2{font-size:22px;margin:0}
.sec-head a{font-size:13px;white-space:nowrap}

/* ---------- 首页 ---------- */
.hero{padding:var(--sp-hero) 0 0}
.hero h1{font-size:var(--fs-hero);margin:0 0 14px;line-height:1.12}
.hero .sub{margin:0 0 26px;font-size:16px;color:var(--mut);line-height:1.75}
.hero-btns{display:flex;gap:12px;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;border-radius:14px;
  padding:13px 24px;min-height:48px;font-size:15px;font-weight:700;cursor:pointer;
  font-family:inherit;border:0;transition:opacity var(--dur-2) var(--ease),transform var(--dur-1) var(--ease)}
.btn:hover{text-decoration:none}
.btn:active{transform:scale(.97)}
.btn-primary{background:var(--ink);color:#fff}
.btn-primary:hover{opacity:.88}
.btn-secondary{background:var(--card);color:var(--ink);border:1px solid var(--line)}
.btn-secondary:hover{border-color:#C7C7CC}
.hero-fig{margin:34px 0 0}
.hero-fig img{display:block;width:100%;height:auto;aspect-ratio:16/10;object-fit:cover;
  border-radius:20px;box-shadow:var(--shadow)}
.hero-fig figcaption{margin-top:8px;font-size:12px;color:var(--mut)}
.today-mini{display:block;background:var(--card);border-radius:var(--radius);
  overflow:hidden;box-shadow:var(--shadow);color:inherit}
.today-mini:hover{text-decoration:none}
.today-mini img{display:block;width:100%;height:auto;aspect-ratio:16/8;object-fit:cover}
.today-mini .tm-body{padding:18px 20px}
.today-mini .tm-date{font-size:12px;color:var(--mut);letter-spacing:.06em;margin-bottom:6px}
.today-mini .tm-title{font-size:var(--fs-lg);font-weight:700;margin-bottom:6px}
.today-mini .tm-ex{font-size:14px;color:var(--mut);line-height:1.7}
.link-rows{list-style:none;background:var(--card);border-radius:var(--radius);
  overflow:hidden;box-shadow:var(--shadow)}
.link-rows li{border-top:1px solid var(--line)}
.link-rows li:first-child{border-top:0}
.link-rows a{display:flex;align-items:center;gap:12px;padding:15px 18px;color:var(--ink)}
.link-rows a:hover{text-decoration:none;background:var(--soft)}
.link-rows .t{flex:1 1 auto}
.link-rows .t b{display:block;font-size:15px;font-weight:700}
.link-rows .t span{display:block;font-size:13px;color:var(--mut)}
.link-rows .arr{color:#C7C7CC;font-size:14px}

/* ---------- 输入 / 按钮 ---------- */
.askbox{background:var(--card);border:1px solid var(--line);border-radius:18px;
  padding:14px 16px 12px;box-shadow:var(--shadow);transition:border-color var(--dur-2) var(--ease),box-shadow var(--dur-2) var(--ease)}
.askbox:focus-within{border-color:#C7C7CC;box-shadow:0 0 0 4px rgba(0,122,255,.08),var(--shadow)}
.askbox textarea{width:100%;border:0;background:transparent;color:var(--ink);outline:none;
  resize:none;font-family:inherit;font-size:16px;line-height:1.65;padding:4px 2px;min-height:58px}
.askbox textarea::placeholder{color:#AEAEB2}
.askbox-foot{display:flex;align-items:center;gap:8px;margin-top:8px}
.ghost{border:0;background:transparent;color:var(--mut);border-radius:999px;
  padding:8px 14px;min-height:36px;font-family:inherit;font-size:13px;font-weight:600;
  cursor:pointer}
.ghost:hover{background:var(--soft);color:var(--ink)}
.send-btn{margin-left:auto;width:42px;height:42px;flex:0 0 auto;border:0;border-radius:50%;
  background:var(--blue);color:#fff;font-size:19px;font-weight:700;line-height:1;cursor:pointer;
  transition:transform var(--dur-1) var(--ease),opacity var(--dur-2) var(--ease)}
.send-btn:hover{opacity:.88}
.send-btn:active{transform:scale(.93)}
.send-btn:disabled{opacity:.4;cursor:default}
.page-note{margin:10px 2px 0;font-size:13px;color:var(--mut)}

/* ---------- 聊天 ---------- */
.chat-card{background:var(--card);border-radius:var(--radius);padding:20px;
  margin:var(--sp-card) 0 0;box-shadow:var(--shadow)}
.card-head{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:4px}
.card-head h3{font-size:15px;margin:0}
.badge{font-size:12px;color:var(--mut);background:var(--soft);border-radius:999px;
  padding:3px 11px;white-space:nowrap}
.chat{max-height:440px;overflow:auto;padding:8px 2px;scroll-behavior:smooth}
.msg{display:flex;gap:10px;margin:15px 0;align-items:flex-end;animation:rise .3s var(--ease)}
@keyframes rise{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}
.msg .av{flex:0 0 30px;width:30px;height:30px;border-radius:50%;display:grid;
  place-items:center;font-size:15px;background:var(--soft);color:var(--mut);overflow:hidden;line-height:1}
.msg .av img{width:100%;height:100%;object-fit:cover;display:block}
.msg .bd{max-width:78%;min-width:0}
.msg .who{font-size:11px;color:var(--mut);margin-bottom:4px}
.msg .txt{padding:11px 15px;border-radius:18px;background:var(--soft);font-size:15px;
  line-height:1.65;white-space:pre-wrap;word-break:break-word}
.msg.me{flex-direction:row-reverse}
.msg.me .bd{display:flex;flex-direction:column;align-items:flex-end}
.msg.me .who{text-align:right}
.msg.me .txt{background:var(--ink);color:#fff;border-bottom-right-radius:6px}
.msg.her .txt{border-bottom-left-radius:6px}
.dots{display:inline-flex;gap:5px;align-items:center;padding:6px 4px}
.dots i{width:7px;height:7px;border-radius:50%;background:var(--mut);opacity:.35;
  animation:blink 1.2s var(--ease) infinite}
.dots i:nth-child(2){animation-delay:.18s}
.dots i:nth-child(3){animation-delay:.36s}
@keyframes blink{0%,100%{opacity:.25;transform:translateY(0)}50%{opacity:1;transform:translateY(-3px)}}
.askbox.in-chat{margin:14px 0 0;box-shadow:none;background:var(--soft);border-radius:15px;
  padding:10px 12px 8px}
.askbox.in-chat textarea{min-height:38px;font-size:15px}
.askbox.in-chat .askbox-foot{margin-top:0}
.note{color:var(--mut);font-size:12px;margin:10px 0 0}

/* ---------- 表单 ---------- */
input,textarea,button{font-family:inherit}
input::placeholder,textarea::placeholder{color:#AEAEB2}
input,textarea{width:100%;padding:12px 14px;border:1px solid var(--line);border-radius:12px;
  background:var(--soft);color:var(--ink);outline:none;font-size:15px;transition:border-color var(--dur-2) var(--ease),box-shadow var(--dur-2) var(--ease)}
input:focus,textarea:focus{border-color:var(--blue);background:#fff;box-shadow:0 0 0 4px rgba(0,122,255,.1)}
textarea{resize:vertical;min-height:76px}
.stack{display:flex;flex-direction:column;gap:10px;margin-top:14px}
.stack button[type=submit]{background:var(--ink);color:#fff;border:0;border-radius:12px;
  padding:13px;font-size:15px;font-weight:700;cursor:pointer;
  transition:opacity var(--dur-2) var(--ease),transform var(--dur-1) var(--ease)}
.stack button[type=submit]:active{transform:scale(.98)}
.stack button[type=submit]:hover{opacity:.88}
.stack button[type=submit]:disabled{opacity:.5;cursor:default}
.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-top:6px}
.row button{background:var(--ink);color:#fff;border:0;border-radius:12px;padding:10px 18px;
  cursor:pointer;font-weight:600;font-size:14px}
.hint{color:var(--mut);font-size:13px;margin:10px 0}

/* ---------- 留言墙 ---------- */
.login-cta{background:var(--card);border-radius:var(--radius);padding:22px;text-align:center;
  box-shadow:var(--shadow);margin-top:14px}
.login-cta p{margin:0 0 14px;font-size:14px;color:var(--mut)}
.login-cta .btn{min-height:44px;padding:11px 28px}
.wall{margin-top:6px}
.item{background:var(--card);border-radius:var(--radius);padding:16px 18px;margin-top:var(--sp-card);
  box-shadow:var(--shadow)}
.item .hd{display:flex;justify-content:space-between;gap:10px;align-items:baseline}
.item .nm{font-weight:700;font-size:14px}
.item .tm{font-size:12px;color:var(--mut);white-space:nowrap;font-variant-numeric:tabular-nums}
.item .tx{margin-top:6px;font-size:15px;line-height:1.75;white-space:pre-wrap;word-break:break-word}
.cmts{margin-top:10px}
.cmt-list{padding-left:12px;border-left:2px solid var(--line);display:flex;flex-direction:column;gap:2px}
.cmt{display:flex;gap:6px;align-items:baseline;font-size:13px;padding:3px 0;flex-wrap:wrap}
.cmt .cnm{font-weight:700;white-space:nowrap}
.cmt .ctx{flex:1 1 auto;word-break:break-word;white-space:pre-wrap}
.cmt .ctm{font-size:11px;color:var(--mut);white-space:nowrap}
.cbar{display:flex;align-items:center;gap:10px;margin-top:8px}
.ccnt{font-size:12px;color:var(--mut)}
.cbtn{background:transparent;border:0;color:var(--blue);font-family:inherit;font-size:13px;
  font-weight:600;cursor:pointer;padding:8px 0;min-height:36px}
.cmtform{display:flex;gap:8px;margin-top:8px}
.cmtform input{flex:1 1 auto;background:#fff;font-size:13px}
.cmtform button{flex:0 0 auto;border:0;border-radius:11px;background:var(--ink);
  color:#fff;font-size:13px;font-weight:700;padding:0 18px;min-height:42px;cursor:pointer}
.cmtform button:disabled{opacity:.5;cursor:default}
.more{display:block;margin:20px auto 2px;background:var(--card);border:1px solid var(--line);
  border-radius:999px;padding:11px 26px;min-height:44px;font-family:inherit;font-size:13px;
  font-weight:700;color:var(--ink);cursor:pointer}
.more:hover{border-color:#C7C7CC}
.empty-state{background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);
  margin-top:12px;overflow:hidden;text-align:center}
.empty-state img{display:block;width:100%;height:auto;aspect-ratio:16/9;object-fit:cover}
.empty-state p{margin:0;padding:16px;font-size:14px;color:var(--mut)}

/* ---------- 文章 ---------- */
.essay-card{background:var(--card);border-radius:var(--r-card);box-shadow:var(--shadow);
  overflow:hidden;margin-top:var(--sp-card)}
.essay-card img.cover{display:block;width:100%;height:auto;aspect-ratio:16/9;object-fit:cover}
.essay-inner{padding:clamp(20px,3.6vw,36px)}
.essay-date{margin:0 0 10px;color:var(--mut);font-size:var(--fs-cap);letter-spacing:.08em}
.essay-title{font-size:var(--fs-title);font-weight:700;line-height:1.35;margin:0 0 18px}
.essay-title::after{content:"";display:block;width:40px;height:3px;border-radius:2px;
  background:var(--ink);margin-top:12px}
.essay-body{font-family:var(--font-serif);
  font-size:17px;line-height:1.85;color:#242428;letter-spacing:0}
.essay-body p{margin:0 0 .9em}
.essay-body p,.prose p{text-wrap:pretty}
.essay-body p:last-child{margin-bottom:0}
.essay-meta{margin:20px 0 0;padding-top:12px;border-top:1px solid var(--line);
  color:var(--mut);font-size:12px}
.essay-loading{margin:0;padding:28px 0;text-align:center;color:var(--mut);font-size:14px}
.past-list{list-style:none;background:var(--card);border-radius:var(--radius);
  overflow:hidden;box-shadow:var(--shadow);margin-top:var(--sp-card)}
.past-list li{border-top:1px solid var(--line)}
.past-list li:first-child{border-top:0}
.past-btn{display:flex;align-items:center;gap:14px;width:100%;padding:14px 16px;
  background:transparent;border:0;cursor:pointer;text-align:left;font-family:inherit;color:inherit}
.past-btn:hover{background:var(--soft)}
.past-btn-card{align-items:center}
.past-thumb{flex:0 0 76px;width:76px;height:58px;border-radius:10px;object-fit:cover;display:block}
.past-txt{flex:1 1 auto;min-width:0;display:flex;align-items:baseline;gap:12px}
.past-hero{display:block;width:100%;height:auto;aspect-ratio:16/9;object-fit:cover;border-radius:12px;margin:14px 0 4px}
.past-full-date{margin:10px 0 12px;color:var(--mut);font-size:var(--fs-cap);letter-spacing:.06em}
.past-date{flex:0 0 auto;color:var(--mut);font-size:12.5px;font-variant-numeric:tabular-nums}
.past-title{flex:1 1 auto;font-size:15px;font-weight:600}
.past-n{flex:0 0 auto;color:var(--mut);font-size:12px}
.past-arrow{flex:0 0 auto;color:#C7C7CC;font-size:11px;transition:transform .2s}
.past-item.open .past-arrow{transform:rotate(180deg)}
.past-full{display:none;padding:2px 20px 22px}
.past-item.open .past-full{display:block;animation:expand .28s var(--ease)}
.past-full .essay-body{font-size:15px}
.past-loading{padding:0 20px 18px;color:var(--mut);font-size:13px}
@keyframes expand{from{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:none}}

/* ---------- 关于 ---------- */
.about-fig{margin:16px 0 0}
.about-fig img{display:block;width:100%;height:auto;aspect-ratio:1/1;object-fit:cover;
  border-radius:20px;box-shadow:var(--shadow)}
.prose{margin-top:18px;max-width:600px}
.prose p{margin:0 0 14px;font-size:15px;line-height:1.85}
.prose .dim{font-size:14px;color:var(--mut)}
.legal{margin-top:16px;border-top:1px solid var(--line);padding-top:12px}
.legal summary{cursor:pointer;font-size:14px;font-weight:700;padding:6px 0;list-style:none}
.legal summary::-webkit-details-marker{display:none}
.legal summary::before{content:"▸ "}
.legal[open] summary::before{content:"▾ "}
.legal p{font-size:14px;color:var(--mut);margin:8px 0 0}

/* ---------- 公告浮条 / 页脚 ---------- */
.notice{position:fixed;left:50%;transform:translateX(-50%);bottom:22px;z-index:150;
  display:flex;align-items:center;gap:12px;background:rgba(28,28,30,.92);color:#fff;
  border-radius:999px;padding:10px 10px 10px 20px;box-shadow:var(--shadow-lg);
  max-width:calc(100vw - 40px);animation:slideup .45s var(--ease)}
@keyframes slideup{from{opacity:0;transform:translate(-50%,16px)}to{opacity:1;transform:translate(-50%,0)}}
.notice-txt{margin:0;font-size:13px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.notice-x{flex:0 0 auto;background:rgba(255,255,255,.16);border:0;color:#fff;font-size:15px;
  width:30px;height:30px;border-radius:50%;line-height:1;padding:0;cursor:pointer}
.foot{margin-top:var(--sp-10);padding:22px 0 30px;border-top:1px solid var(--line)}
.foot p{margin:0;font-size:12.5px;color:var(--mut);text-align:center;font-variant-numeric:tabular-nums}
main{padding-bottom:10px}

/* ---------- 头像 ---------- */
.avatar{width:32px;height:32px;border-radius:50%;display:grid;place-items:center;
  background:var(--soft);font-size:16px;overflow:hidden;flex:0 0 auto;line-height:1}
.avatar.sm{width:28px;height:28px;font-size:14px}
.avatar img{width:100%;height:100%;object-fit:cover;display:block}
.emoji-pick{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0}
.emoji-pick button.emoji{background:#fff;border:1px solid var(--line);font-size:22px;
  padding:8px 12px;border-radius:12px;line-height:1;cursor:pointer;color:var(--ink)}
.emoji-pick button.emoji.on{border-color:var(--ink);background:var(--soft)}

/* ---------- 弹窗 ---------- */
.modal{position:fixed;inset:0;z-index:200;display:flex;align-items:center;justify-content:center;padding:18px}
.modal-mask{position:absolute;inset:0;background:rgba(0,0,0,.4);animation:fadein .2s var(--ease)}
.modal-card{position:relative;z-index:1;width:min(400px,100%);max-height:88vh;overflow:auto;
  background:var(--card);border-radius:22px;padding:26px;box-shadow:var(--shadow-lg);
  animation:pop .28s var(--ease)}
@keyframes pop{from{opacity:0;transform:scale(.96) translateY(10px)}to{opacity:1;transform:none}}
@keyframes fadein{from{opacity:0}to{opacity:1}}
.modal-x{position:absolute;top:10px;right:12px;background:transparent;border:0;color:var(--mut);
  font-size:22px;line-height:1;padding:6px 10px;cursor:pointer;border-radius:10px}
.modal-x:hover{color:var(--ink)}
.modal-title{margin:0 0 16px;font-size:20px}
.seg{display:flex;gap:5px;background:var(--soft);border-radius:12px;padding:4px;margin:0 0 16px}
.seg button{flex:1;background:transparent;color:var(--mut);border:0;border-radius:10px;
  padding:10px 0;min-height:42px;font-size:14px;font-weight:700;cursor:pointer;font-family:inherit}
.seg button.on{background:#fff;color:var(--ink);box-shadow:0 1px 4px rgba(0,0,0,.1)}

/* ---------- 渐入 ---------- */
.reveal{transition:opacity .6s var(--ease),transform .6s var(--ease)}
.js .reveal{opacity:0;transform:translateY(20px)}
.js .reveal.visible{opacity:1;transform:translateY(0)}

/* ---------- 无障碍 ---------- */
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;
  clip:rect(0 0 0 0);white-space:nowrap;border:0}
.skip{position:absolute;left:-9999px;top:0;z-index:300;background:var(--ink);color:#fff;
  padding:10px 16px;border-radius:0 0 12px 0;font-size:14px;font-weight:600}
.skip:focus{left:0;top:0;color:#fff}
a:focus-visible,button:focus-visible,input:focus-visible,textarea:focus-visible,
summary:focus-visible{outline:2px solid var(--blue);outline-offset:2px}
.warnbox{color:#8A4B00;border:1px solid #E5C07B;background:#FFF8EC;border-radius:12px;
  padding:10px 14px;font-size:13px;margin-top:14px}

/* ---------- 深色 ---------- */
@media (prefers-color-scheme:dark){
  :root{
    color-scheme:dark;
    --bg:#000000; --card:#1C1C1E;
    --ink:#F2F2F7; --mut:#98989F;
    --line:#38383A; --soft:#2C2C2E;
    --blue:#0A84FF;
    --shadow:0 1px 2px rgba(0,0,0,.5),0 8px 30px rgba(0,0,0,.5);
    --shadow-lg:0 20px 60px rgba(0,0,0,.6);
  }
  .nav{background:rgba(0,0,0,.72)}
  ::selection{background:#0A84FF;color:#fff}
  .msg .txt{background:#2C2C2E}
  .msg.me .txt{background:#F2F2F7;color:#000}
  .btn-login,.stack button[type=submit],.row button,.cmtform button{background:#F2F2F7;color:#000}
  .btn-primary{background:#F2F2F7;color:#000}
  .send-btn{background:var(--blue)}
  .brand svg rect{fill:#F2F2F7}
  .brand svg g{stroke:#000}
  .seg button.on{background:#38383A;color:var(--ink)}
  .emoji-pick button.emoji{background:#2C2C2E}
  .cmtform input,input:focus,textarea:focus{background:var(--card)}
  .essay-body{color:#E5E5EA}
  .link-rows .arr{color:#48484A}
  .past-arrow{color:#48484A}
  .toast{background:rgba(242,242,247,.95);color:#000}
}

/* ---------- 响应式 ---------- */
@media (max-width:720px){
  .wrap{padding:0 16px}
  .nav-inner{padding:10px 12px;gap:10px}
  .tabs{display:none}
  .nav-toggle{display:block}
  .brand{font-size:15px}
  .hero{padding:52px 0 0}
  .page-head{padding:38px 0 4px}
  .sec{padding:28px 0 0}
  .nav-drawer{position:fixed;inset:0;z-index:150;background:var(--bg);
    display:flex;flex-direction:column;justify-content:center;padding:0 32px;gap:4px}
  .nav-drawer[hidden]{display:none}
  .nav-drawer a{font-size:28px;font-weight:750;padding:10px 0;border-bottom:1px solid var(--line);
    color:var(--ink)}
  .nav-drawer a:first-child{border-top:1px solid var(--line)}
  .nav-drawer a:hover{text-decoration:none}
  .nav-drawer a.active{color:var(--mut)}
  .drawer-x{position:absolute;top:14px;right:18px;background:none;border:0;font-size:24px;
    color:var(--ink);cursor:pointer;min-width:44px;min-height:44px}
  .chat{max-height:320px}
  .about-fig img{aspect-ratio:16/10}
  .notice-txt{font-size:12px}
}
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.001ms !important;animation-iteration-count:1 !important;
    transition-duration:.001ms !important;scroll-behavior:auto !important}
  .chat{scroll-behavior:auto}
  ::view-transition-group(*),::view-transition-old(*),::view-transition-new(*){animation:none !important}
}
/* ---------- v23 跨页转场 / 按压态 / 反馈 ---------- */
@view-transition{navigation:auto}
.tabs a,.link-rows a,.ghost,.more,.cbtn,.cmtform button,.dropdown button,.past-btn,
.notice-x,.modal-x,.user-btn,.emoji-pick button.emoji,.row button{transition:transform var(--dur-1) var(--ease)}
.tabs a:active,.link-rows a:active,.ghost:active,.more:active,.cbtn:active,.cmtform button:active,
.dropdown button:active,.past-btn:active,.notice-x:active,.modal-x:active,.user-btn:active{transform:scale(.97)}
.emoji-pick button.emoji:active{transform:scale(.92)}
.row button:active{transform:scale(.98)}
.item,.past-item{animation:rise .42s var(--ease) both;animation-delay:calc(var(--i,0)*40ms)}
button.loading{pointer-events:none}
button.loading::before{content:"";display:inline-block;width:1em;height:1em;margin-right:.5em;
  border:2px solid currentColor;border-top-color:transparent;border-radius:50%;vertical-align:-.15em;
  animation:spin .7s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.toast{position:fixed;left:50%;bottom:30px;z-index:320;max-width:calc(100vw - 48px);
  background:rgba(28,28,30,.92);color:#fff;font-size:13px;padding:10px 18px;border-radius:999px;
  box-shadow:var(--shadow-lg);opacity:0;transform:translate(-50%,10px);pointer-events:none;
  transition:opacity var(--dur-3) var(--ease),transform var(--dur-3) var(--ease)}
.toast.on{opacity:1;transform:translate(-50%,0)}
.err-page{padding-top:var(--sp-hero);text-align:center}
.err-page h1{font-size:clamp(32px,5.2vw,44px);margin:0 0 10px}
.err-page .hint{font-size:15px}
.err-page .hero-btns{justify-content:center;margin-top:22px}
[hidden]{display:none !important}