:root{
  --bg:#fbfaf8; --fg:#0f0f0f; --muted:#9a9a96; --hair:#e8e6e1;
  --bg2:#fff; --bubble:#f1efeB; --mine:#0f0f0f; --minefg:#fbfaf8;
  --max:1020px;
}
@media (prefers-color-scheme: dark){
  :root{
    --bg:#0a0a0a; --fg:#f2f0eb; --muted:#6e6e6a; --hair:#1e1e1c;
    --bg2:#111110; --bubble:#1c1c1a; --mine:#f2f0eb; --minefg:#0a0a0a;
  }
}
*{margin:0;padding:0;box-sizing:border-box}
html{font-size:16px;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
html,body{height:100%}
/* 藏条不藏滚（全站约定）：内部滚动容器一律不显滚动条——本站既有语言（#member-list 早就如此），
   body 锁成固定框架后 #timeline/#rooms/#room-box/#login-view 等各自成滚动容器，
   Windows 默认滚动条又粗又灰会很出戏。只关视觉：滚轮、触控惯性、键盘、程序化 scrollTop 全部照常。 */
*{scrollbar-width:none;-ms-overflow-style:none}
*::-webkit-scrollbar{width:0;height:0;display:none}
body{height:100dvh;overflow:hidden;background:var(--bg);color:var(--fg);
  font-family:"Inter","SF Pro Display",-apple-system,BlinkMacSystemFont,"Helvetica Neue",Helvetica,"PingFang SC","Microsoft YaHei",Arial,sans-serif;
  display:flex;flex-direction:column}
body::before{content:"";position:fixed;inset:14px;border:1px solid var(--hair);pointer-events:none}
#app{max-width:var(--max);width:100%;margin:0 auto;padding:20px 28px 20px;flex:1 1 auto;display:flex;flex-direction:column;min-height:0}
#chat-view{display:flex;flex-direction:column;flex:1 1 auto;min-height:0}
#login-view{margin:auto;overflow-y:auto;max-height:calc(100dvh - 40px)}
.eyebrow{font-family:"JetBrains Mono","SF Mono",ui-monospace,monospace;font-size:11px;letter-spacing:.18em;text-transform:uppercase;color:var(--muted)}
h1{font-family:"Instrument Serif","Newsreader",Georgia,"Songti SC",serif;font-size:clamp(2.2rem,6vw,3.2rem);font-weight:400;letter-spacing:-.04em;line-height:1;margin:10px 0 8px}
h1 i{font-style:italic}
.sub{color:var(--muted);font-size:13px;margin-bottom:18px}
.card{max-width:380px;margin:8vh auto;width:100%;border:1px solid var(--hair);padding:28px;background:var(--bg)}
label{display:block;font-family:"JetBrains Mono",ui-monospace,monospace;font-size:11px;letter-spacing:.14em;text-transform:uppercase;color:var(--muted);margin:0 0 12px}
input{width:100%;background:var(--bg2);border:1px solid var(--hair);color:var(--fg);font-size:15px;padding:10px 12px;margin-top:6px}
input:focus{outline:none;border-color:var(--fg)}
button{cursor:pointer;font-size:13px;letter-spacing:.06em}
button.action{appearance:none;border:1px solid var(--fg);background:var(--fg);color:var(--bg);padding:10px 18px}
button.ghost{appearance:none;border:1px solid var(--hair);background:transparent;color:var(--fg);padding:10px 14px}
button.ghost:hover{border-color:var(--fg)}
.error{color:#c0392b;font-size:13px;min-height:1.2em;margin-top:10px}
header{display:flex;gap:14px;align-items:flex-end;border-bottom:1px solid var(--hair);padding-bottom:14px}
header .title{font-family:"Instrument Serif",Georgia,serif;font-size:1.6rem;font-weight:400;letter-spacing:-.02em}
#me{color:var(--muted);font-size:12px;flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-family:"JetBrains Mono",ui-monospace,monospace}
button.go{flex-shrink:0}
#room-list .go{flex-shrink:0}
.frow{display:flex;gap:6px}
.frow input{flex:1;min-width:0}
.foot{margin-top:16px;font-size:11px;color:var(--muted);font-family:"JetBrains Mono",ui-monospace,monospace}
header .ghost{padding:6px 10px;font-size:12px}
#room-title.clickable{cursor:pointer}
button.go{font-weight:700}
#send-form svg{display:block}
.msg.mine .file-card button{border:1px solid var(--minefg);color:var(--minefg);background:transparent;border-radius:8px;padding:8px 12px}
button.go{border:1px solid var(--fg);background:var(--fg);color:var(--bg);font-family:"JetBrains Mono",ui-monospace,monospace;font-size:11px;letter-spacing:.1em;padding:6px 12px;white-space:nowrap;border-radius:8px}
#main{transition:gap .15s}
body.side-collapsed #rooms{display:none}
#room-title.hint{font-family:inherit;font-size:15px;font-weight:400;color:var(--muted)}
#room-list li{border-radius:10px}
.card{border-radius:12px}
input{border-radius:8px}
body.side-collapsed #room{border-left:none;padding-left:0}
@media (max-width:700px){
  #rooms{border:1px solid var(--hair);border-radius:12px;padding:12px;background:var(--bg)}
}
#main{display:flex;gap:20px;margin-top:16px;flex:1 1 auto;min-height:0}
#rooms{width:250px;flex-shrink:0;display:flex;flex-direction:column;min-height:0}
#room-box{flex:1 1 auto;min-height:0;overflow-y:auto;border:1px solid var(--hair);border-radius:12px;padding:10px;display:flex;flex-direction:column;gap:8px}
.side-divider{height:1px;background:var(--hair);margin:10px 0;flex-shrink:0}
#io-form{flex-shrink:0}
#room-list{overflow-y:auto;min-height:0}
.side-label{font-family:"JetBrains Mono",ui-monospace,monospace;font-size:11px;letter-spacing:.18em;text-transform:uppercase;color:var(--muted)}
#room-list{list-style:none;display:flex;flex-direction:column;gap:8px}
#invite-list{list-style:none;display:flex;flex-direction:column;gap:8px}
#room-list li,#invite-list li{display:flex;gap:8px;align-items:center;border:1px solid var(--hair);padding:8px 8px 8px 12px;background:var(--bg)}
#room-list li{display:flex;gap:8px;align-items:center;border:1px solid var(--hair);padding:8px 8px 8px 12px;background:var(--bg)}
#room-list li.sel{border-color:var(--fg)}
#room-list .nm,#invite-list .nm{flex:1;font-size:14px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;min-width:0}
#room-list .enter,#invite-list .enter,#member-list .enter{width:32px;height:32px;min-width:32px;border-radius:50%;border:1px solid var(--hair);background:var(--bg2);color:var(--fg);display:flex;align-items:center;justify-content:center;padding:0;flex-shrink:0}
#room-list .enter:hover,#invite-list .enter:hover,#member-list .enter:hover{border-color:var(--fg)}
#room-list .enter.unread{border:2px dashed var(--fg)}
#room-list .enter svg,#invite-list .enter svg,#member-list .enter svg{display:block}
#invite-list .decline{width:32px;height:32px;min-width:32px;border-radius:50%;border:1px solid var(--hair);background:transparent;color:var(--muted);display:flex;align-items:center;justify-content:center;padding:0;flex-shrink:0}
#invite-list .decline:hover{color:var(--fg);border-color:var(--fg)}
#invite-list .decline svg{display:block}
button.action,button.ghost{border-radius:8px}
#io-form{display:flex;flex-direction:column;gap:8px}
#io-form input{font-size:13px;margin-top:0;min-width:0}
#room{flex:1 1 auto;display:flex;flex-direction:column;min-width:0;min-height:0;border-left:1px solid var(--hair);padding-left:20px}
#room-title{font-family:"Instrument Serif",Georgia,serif;font-size:1.25rem;padding-bottom:10px}
.notice{font-size:13px;color:#8a6d1a;background:#fdf6e3;border:1px solid #e8d9a8;padding:8px 12px;margin-bottom:10px}
@media (prefers-color-scheme: dark){.notice{color:#d8b84a;background:#1a1608;border-color:#4a3f1a}}
#timeline{flex:1 1 auto;overflow-y:auto;min-height:0;padding:6px 2px;display:flex;flex-direction:column;gap:10px}
.msg{max-width:82%;display:flex;flex-direction:column;align-items:flex-start}
.msg .meta{font-size:11px;color:var(--muted);margin-bottom:3px;font-family:"JetBrains Mono",ui-monospace,monospace}
.msg .body{background:var(--bubble);border-radius:2px 14px 14px 14px;padding:8px 13px;font-size:15px;line-height:1.6;white-space:normal;word-break:break-word}
.body> :first-child{margin-top:0}
.body> :last-child{margin-bottom:0}
.body p{margin:0 0 6px;white-space:normal}
.body p:last-child{margin:0}
.body pre{background:rgba(127,127,127,.12);padding:8px 10px;border-radius:8px;overflow-x:auto;margin:6px 0;white-space:pre}
.body code{font-family:"JetBrains Mono",ui-monospace,monospace;font-size:13px}
.body ul,.body ol{padding-left:20px;margin:4px 0}
.body table{border-collapse:collapse;margin:6px 0;font-size:13px}
.body th,.body td{border:1px solid var(--hair);padding:4px 8px}
.body blockquote{border-left:3px solid var(--hair);margin:6px 0;padding:2px 0 2px 10px;color:var(--muted)}
.body .katex-display{margin:6px 0;overflow-x:auto;overflow-y:hidden}
.body a{color:inherit}
.msg.mine{align-self:flex-end;align-items:flex-end}
.msg.mine .body{background:var(--mine);color:var(--minefg);border-radius:14px 2px 14px 14px}
.msg.sys{align-self:center}
.msg.sys .body{background:none;color:var(--muted);font-size:13px;padding:2px}
.file-card{display:flex;gap:10px;align-items:center;background:var(--bubble);border:1px solid var(--hair);border-radius:12px;padding:10px 12px;max-width:440px}
.msg.mine .file-card{background:var(--mine);color:var(--minefg);border-color:transparent}
.file-card .fn{font-size:14px;word-break:break-all}
.file-card .fs{font-size:11px;color:var(--muted);font-family:"JetBrains Mono",ui-monospace,monospace}
.msg.mine .file-card .fs{color:inherit;opacity:.7}
.file-card button{flex-shrink:0}
#more.loadmore{display:flex;align-items:center;gap:12px;width:100%;background:none;border:none;color:var(--muted);font-size:12px;letter-spacing:.06em;padding:6px 0;cursor:pointer}
#more.loadmore::before,#more.loadmore::after{content:"";flex:1;height:1px;background:var(--hair)}
#more.loadmore:hover{color:var(--fg)}
#manage{border:1px solid var(--hair);border-radius:12px;padding:12px;margin-bottom:10px;background:var(--bg2)}
#manage[hidden]{display:none}
#member-list{list-style:none;display:flex;flex-direction:column;gap:6px;margin:8px 0}
#member-list li{font-size:13px;display:flex;gap:8px;align-items:baseline}
#member-list .mx{color:var(--muted);font-size:11px;font-family:"JetBrains Mono",ui-monospace,monospace;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
#manage-id a{color:var(--muted);text-decoration:none}
#manage-id a:hover{color:var(--fg)}
#member-list .nm{flex:1;font-size:14px;white-space:nowrap;min-width:0;overflow-x:auto;scrollbar-width:none}
#member-list .nm::-webkit-scrollbar{display:none}
#member-list .vdiv{width:1px;align-self:stretch;background:var(--hair);flex-shrink:0;margin:0 2px}
#member-list .kick{width:30px;height:30px;min-width:30px;border-radius:50%;border:1px solid var(--fg);background:var(--fg);color:var(--bg);display:flex;align-items:center;justify-content:center;padding:0;flex-shrink:0}
#member-list .kick svg{display:block}
.frow.btnrow{margin-top:8px}
button.danger{appearance:none;border:1px solid #c0392b;background:transparent;color:#c0392b;padding:10px 14px;font-size:13px;border-radius:8px}
#pagefoot{flex-shrink:0;text-align:center;font-family:"JetBrains Mono",ui-monospace,monospace;font-size:10px;letter-spacing:.1em;color:var(--muted);padding:8px 0 4px;margin-top:6px;border-top:1px solid var(--hair)}
#pagefoot a{color:inherit;text-decoration:none}
.guide{max-width:640px;margin:0 auto;flex:1 1 auto;min-height:0;overflow-y:auto;overscroll-behavior-y:contain;-webkit-overflow-scrolling:touch;padding-bottom:12px;scrollbar-width:none;-ms-overflow-style:none}
.guide::-webkit-scrollbar{width:0;height:0;display:none}
.guide h2{font-family:"Instrument Serif",Georgia,serif;font-weight:400;font-size:1.4rem;margin:26px 0 8px}
.guide p,.guide li{font-size:14px;line-height:1.8}
.guide ul{padding-left:20px}
.guide .en{color:var(--muted)}
.guide code{font-family:"JetBrains Mono",ui-monospace,monospace;font-size:12px;background:var(--bubble);padding:1px 6px;border-radius:6px}
.guide .foot{margin:28px 0 10px;font-size:12px}
.guide .foot a{color:var(--muted)}
#pagefoot a:hover{color:var(--fg)}
#chat-view[hidden],#login-view[hidden],#more[hidden]{display:none}
#send-form{display:flex;gap:8px;align-items:center;padding-top:12px;border-top:1px solid var(--hair)}
#send-form input#msg{flex:1;border-radius:999px;padding:11px 18px;margin-top:0;min-width:0}
.frow .go{align-self:stretch;display:flex;align-items:center;padding:10px 14px}
#attach{border-width:2px}
#send{font-size:20px;font-weight:900}
button.round{width:42px;height:42px;min-width:42px;border-radius:50%;font-size:18px;line-height:1;display:flex;align-items:center;justify-content:center;padding:0}
button.round.action{background:var(--fg);color:var(--bg);border:1px solid var(--fg)}
.meta{font-size:12px;color:var(--muted);padding-top:6px;font-family:"JetBrains Mono",ui-monospace,monospace}
img.preview{max-width:220px;border-radius:10px;display:block;margin-bottom:6px}
@media (max-width:700px){
  body::before{inset:8px}
  #app{padding:24px 16px}
  #main{flex-direction:column}
  #rooms{width:min(300px,86vw);height:auto;position:fixed;top:0;bottom:0;left:0;z-index:50;background:var(--bg);border-right:1px solid var(--hair);padding:14px;overflow-y:auto;box-shadow:8px 0 24px rgba(0,0,0,.08)}
  body.side-collapsed #rooms{transform:translateX(-105%);box-shadow:none}
  #rooms{transition:transform .18s ease}
  #room-box{max-height:none}
  #room{border-left:none;padding-left:0;border-top:none;padding-top:0}
}