:root{
  --bg:#f7f7f8;
  --panel:#ffffff;
  --sidebar:#f4f4f5;
  --line:#e5e7eb;
  --text:#111827;
  --muted:#6b7280;
  --blue:#2563eb;
  --blue-soft:#eff6ff;
  --hover:#f9fafb;
  --active:#e8f0ff;
}
*{box-sizing:border-box}
html,body{height:100%}
body{margin:0;background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
a{text-decoration:none;color:inherit}
.topbar{height:54px;background:#fff;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 18px;position:sticky;top:0;z-index:10}
.brand strong{font-size:17px;letter-spacing:-.01em}
.topbar nav{display:flex;gap:4px}
.topbar nav a{font-size:13px;color:#374151;padding:8px 10px;border-radius:8px}
.topbar nav a:hover{background:#f3f4f6}
button,.primary,.secondary,.new-btn{border:0;border-radius:8px;padding:9px 12px;cursor:pointer;font-weight:700;display:inline-block}
.primary{background:var(--blue);color:#fff}
.secondary{background:#fff;color:#111827;border:1px solid var(--line)}
.new-btn{background:#111827;color:#fff;width:34px;height:34px;display:grid;place-items:center;padding:0}
input,select,textarea{width:100%;border:1px solid var(--line);border-radius:8px;padding:9px;background:#fff;font-size:14px}
textarea{min-height:94px;resize:vertical}
label{display:block;font-size:12px;font-weight:700;color:#374151;margin:10px 0 5px}
.check-line,.check-inline{display:flex;align-items:center;gap:7px;font-weight:600;color:#374151}
.check-line input,.check-inline input{width:auto}
.hint{color:var(--muted);font-size:13px}
.alert{background:#fef2f2;border:1px solid #fecaca;color:#991b1b;padding:10px;border-radius:10px;margin:12px 0}
.login-page{min-height:calc(100vh - 54px);display:grid;place-items:center;padding:24px}
.login-card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:26px;width:min(430px,100%);box-shadow:0 16px 36px rgba(15,23,42,.08)}
.login-card h1{margin:0 0 8px}
.login-card button{width:100%;margin-top:15px}
.slack-layout{height:calc(100vh - 54px);display:grid;grid-template-columns:330px minmax(0,1fr) 300px}
.slack-sidebar{background:var(--sidebar);border-right:1px solid var(--line);overflow:auto;display:flex;flex-direction:column}
.sidebar-head{padding:16px 14px 12px;display:flex;justify-content:space-between;align-items:flex-start}
.sidebar-head h1{font-size:22px;margin:0}
.sidebar-head p{font-size:12px;color:var(--muted);margin:3px 0 0}
.search-details{padding:0 12px 8px}
.search-details summary{cursor:pointer;font-size:12px;color:var(--muted);font-weight:700;padding:4px 2px}
.sidebar-search{display:grid;grid-template-columns:1fr auto;gap:7px;margin-top:6px}
.sidebar-search input{grid-column:1/3}
.sidebar-search button{background:#fff;border:1px solid var(--line);border-radius:8px}
.section-title{font-size:11px;font-weight:900;color:#6b7280;letter-spacing:.06em;padding:11px 14px 6px}
.closed-title{margin-top:10px;border-top:1px solid var(--line);padding-top:14px}
.topic-list{display:flex;flex-direction:column}
.topic-row{padding:10px 13px;margin:2px 8px;border-radius:10px}
.topic-row:hover{background:#fff}
.topic-row.active{background:var(--active)}
.topic-row.unread .row-top strong{font-weight:900;color:#0f3b83}
.row-top{display:flex;justify-content:space-between;gap:8px;align-items:flex-start}
.row-top strong{font-size:14px;line-height:1.32}
.unread-pill{background:var(--blue);color:#fff;border-radius:999px;padding:2px 7px;font-size:11px}
.row-meta{font-size:11px;color:var(--muted);margin-top:4px}
.row-snippet{font-size:12px;color:#4b5563;margin-top:5px;line-height:1.35}
.closed-list .topic-row{opacity:.78}
.empty-small{font-size:12px;color:var(--muted);padding:8px 14px}
.chat-main{background:#fff;display:flex;flex-direction:column;min-width:0}
.chat-head{height:auto;min-height:76px;padding:14px 18px;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;gap:12px;align-items:flex-start}
.chat-head h2{font-size:20px;margin:0 0 6px}
.thread-meta{display:flex;gap:6px;flex-wrap:wrap}
.thread-meta span{background:#f3f4f6;border:1px solid var(--line);border-radius:999px;padding:3px 8px;font-size:12px;color:#374151}
.messages{padding:18px;flex:1;overflow:auto;background:#fff}
.message{display:flex;margin-bottom:13px}
.message.mine{justify-content:flex-end}
.bubble{background:#fff;border:1px solid var(--line);border-radius:14px;padding:11px 13px;max-width:760px;box-shadow:0 4px 12px rgba(15,23,42,.035)}
.message.mine .bubble{background:#eef5ff;border-color:#bfdbfe}
.msg-meta{font-size:12px;color:var(--muted);margin-bottom:7px}
.msg-body{line-height:1.65;font-size:15px;white-space:normal}
.reply-box{border-top:1px solid var(--line);padding:12px 14px;background:#fff;display:grid;gap:8px}
.reply-tools{display:grid;grid-template-columns:180px 1fr;gap:8px;align-items:center}
.reply-box textarea{min-height:76px}
.topic-side{background:#fff;border-left:1px solid var(--line);padding:12px;overflow:auto}
.side-card{border:1px solid var(--line);border-radius:12px;padding:12px;margin-bottom:12px;background:#fff}
.side-card h3{font-size:15px;margin:0 0 10px}
.participant{border-bottom:1px solid var(--line);padding:7px 0;font-size:13px}
.participant span{color:var(--muted);font-size:12px;margin-left:5px}
.participant small{display:block;color:var(--muted);font-size:11px;margin-top:2px}
.mini-form{display:grid;gap:8px;margin-top:10px}
.file-row{display:block;border-bottom:1px solid var(--line);padding:7px 0;font-size:13px;color:var(--blue)}
.file-row small{display:block;color:var(--muted);font-size:11px;margin-top:2px}
.empty-thread{display:grid;place-items:center;text-align:center;background:#fff;padding:40px}
.empty-thread h2{font-size:24px;margin:0 0 8px}
.empty-thread p{color:var(--muted);max-width:520px;line-height:1.7}
.page{max-width:1100px;margin:0 auto;padding:24px}
.compose-card,.table-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:20px;margin-bottom:18px;box-shadow:0 8px 20px rgba(15,23,42,.04)}
.compose-card h1{margin-top:0}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.checklist{border:1px solid var(--line);border-radius:10px;max-height:220px;overflow:auto;padding:8px;background:#fafafa}
.checklist label{margin:0;padding:8px;border-bottom:1px solid #eef0f2;font-weight:500}
.checklist input{width:auto;margin-right:6px}
table{width:100%;border-collapse:collapse}
th,td{border-bottom:1px solid var(--line);padding:10px;text-align:left;font-size:14px;vertical-align:top}
th{font-size:12px;color:var(--muted);background:#f9fafb}
@media(max-width:1080px){
  .slack-layout{grid-template-columns:300px minmax(0,1fr)}
  .topic-side{display:none}
}
@media(max-width:760px){
  .slack-layout{grid-template-columns:1fr;height:auto}
  .slack-sidebar{height:48vh}
  .reply-tools,.grid2{grid-template-columns:1fr}
}

.file-preview{margin:18px 0;border:1px solid var(--line);border-radius:12px;background:#fafafa;padding:14px;min-height:160px}
.file-preview-image{max-width:100%;height:auto;border-radius:10px;display:block;margin:auto}
.file-preview-frame{width:100%;height:70vh;border:0;border-radius:10px;background:#fff}
.file-preview-empty{padding:30px;text-align:center;color:var(--muted)}
.file-actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-top:14px}
.file-actions form{margin:0}
.danger-card{border-color:#fecaca;background:#fff7f7}
.danger{background:#dc2626;color:#fff;border:0;border-radius:8px;padding:9px 12px;cursor:pointer;font-weight:700}

.msg-attachments{margin-top:10px;display:flex;gap:8px;flex-wrap:wrap}
.chat-image{max-width:280px;max-height:240px;border-radius:10px;border:1px solid var(--line);display:block;background:#fff}
.attachment-link{display:inline-block;background:#f3f4f6;border:1px solid var(--line);border-radius:8px;padding:7px 9px;font-size:13px;color:var(--blue);margin-top:4px}