:root{
  --bg:#0a0a18; --panel:#11112a; --panel2:#171735; --line:#262650; --text:#e8e8f6; --muted:#9a9ac4;
  --indigo:#6366f1; --violet:#a855f7; --grad:linear-gradient(135deg,#6366f1,#a855f7);
  --ok:#34d399; --bad:#f87171; --warn:#fbbf24; --radius:14px;
}
*{box-sizing:border-box}
html,body{margin:0;height:100%;background:var(--bg);color:var(--text);
  font:15px/1.55 "Inter","Segoe UI",system-ui,-apple-system,Roboto,Arial,sans-serif}
a{color:#c4b5fd}
button{font:inherit;cursor:pointer}
.app{display:flex;height:100vh;overflow:hidden}
.sidebar{width:280px;flex:none;background:var(--panel);border-right:1px solid var(--line);display:flex;flex-direction:column;padding:18px 14px;gap:12px}
.brand{display:flex;gap:12px;align-items:center;padding:0 6px 6px}
.logo{width:40px;height:40px;border-radius:12px;background:var(--grad);display:grid;place-items:center;font-weight:800;font-size:20px;box-shadow:0 6px 24px #6366f155}
.brand-name{font-weight:800;font-size:20px;letter-spacing:.5px}
.brand-tag{font-size:12px;color:var(--muted)}
.btn{background:var(--panel2);color:var(--text);border:1px solid var(--line);border-radius:10px;padding:9px 16px;transition:.15s}
.btn:hover{border-color:var(--indigo)}
.btn.primary{background:var(--grad);border:0;color:#fff;font-weight:600}
.btn.primary:hover{filter:brightness(1.1)}
.btn.small{padding:4px 10px;font-size:13px}
.btn.danger:hover{border-color:var(--bad);color:var(--bad)}
.btn:disabled{opacity:.5;cursor:default}
.wide{width:100%}
.nav{display:flex;flex-direction:column;gap:2px}
.nav a,.chat-item{display:block;padding:8px 10px;border-radius:10px;color:var(--text);text-decoration:none;font-size:14px}
.nav a:hover,.chat-item:hover{background:var(--panel2)}
.nav a.active,.chat-item.active{background:#6366f122;box-shadow:inset 3px 0 0 var(--indigo)}
.section-label{font-size:11px;text-transform:uppercase;letter-spacing:1px;color:var(--muted);padding:8px 10px 0}
.chat-list{flex:1;overflow-y:auto;display:flex;flex-direction:column;gap:2px}
.chat-item{display:flex;justify-content:space-between;align-items:center;gap:6px;cursor:pointer}
.chat-item span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.chat-item .del{opacity:0;background:none;border:0;color:var(--muted);padding:0 4px}
.chat-item:hover .del{opacity:1}
.sidebar-foot{font-size:12px;color:var(--muted);padding:6px 10px;border-top:1px solid var(--line)}
.main{flex:1;display:flex;min-width:0}
.view{flex:1;display:flex;flex-direction:column;min-width:0}
.view[hidden]{display:none}
.topbar{display:flex;align-items:center;gap:12px;padding:14px 22px;border-bottom:1px solid var(--line);background:#0d0d20}
.chat-title{font-weight:700;font-size:16px;flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.model-pick{font-size:12px;color:var(--muted);display:flex;align-items:center;gap:8px}
select,input,textarea{background:var(--panel2);color:var(--text);border:1px solid var(--line);border-radius:10px;padding:8px 10px;font:inherit}
select:focus,input:focus,textarea:focus{outline:none;border-color:var(--indigo)}
.icon-btn{background:none;border:0;color:var(--text);font-size:20px}
.menu-btn{display:none}
.messages{flex:1;overflow-y:auto;padding:26px max(22px,calc((100% - 860px)/2));display:flex;flex-direction:column;gap:18px}
.msg{display:flex;gap:12px;max-width:100%}
.msg .avatar{width:32px;height:32px;border-radius:10px;flex:none;display:grid;place-items:center;font-weight:700;font-size:14px}
.msg.user{flex-direction:row-reverse}
.msg.user .avatar{background:#2a2a55}
.msg.assistant .avatar{background:var(--grad)}
.bubble{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:12px 16px;max-width:min(720px,85%);overflow-wrap:anywhere}
.msg.user .bubble{background:#25225a;border-color:#3b3880}
.bubble p{margin:.3em 0}
.bubble ul,.bubble ol{margin:.3em 0;padding-left:1.3em}
.bubble code{background:#00000055;padding:1px 5px;border-radius:5px;font-size:.92em}
.bubble pre{background:#00000066;padding:10px;border-radius:8px;overflow-x:auto}
.bubble h1,.bubble h2,.bubble h3,.bubble h4{margin:.5em 0 .3em;font-size:1.05em}
.msg-foot{display:flex;flex-wrap:wrap;gap:6px;align-items:center;margin-top:8px}
.chip{font-size:12px;border-radius:999px;padding:3px 10px;background:#6366f11f;border:1px solid #6366f155;color:#c7c8ff;cursor:default}
.chip.saved{background:#34d39914;border-color:#34d39955;color:#a7f3d0}
.chip.changed{background:#fbbf2414;border-color:#fbbf2455;color:#fde68a}
.chip.model{background:none;border-color:var(--line);color:var(--muted)}
.fb{margin-left:auto;display:flex;gap:4px}
.fb button{background:none;border:1px solid transparent;border-radius:8px;padding:2px 7px;color:var(--muted);font-size:14px}
.fb button:hover{border-color:var(--line)}
.fb button.on-up{border-color:var(--ok);background:#34d39922}
.fb button.on-down{border-color:var(--bad);background:#f8717122}
.details{font-size:12.5px;color:var(--muted);margin-top:6px;background:#0000002a;border-radius:10px;padding:8px 12px}
.details b{color:var(--text)}
.typing{color:var(--muted);font-style:italic}
.dots::after{content:'';animation:dots 1.2s steps(4) infinite}
@keyframes dots{0%{content:''}25%{content:'.'}50%{content:'..'}75%{content:'...'}}
.error-bubble{background:#f871711a;border:1px solid #f8717166;color:#fecaca;border-radius:var(--radius);padding:10px 14px;align-self:center;max-width:720px}
.composer{display:flex;gap:10px;padding:16px max(22px,calc((100% - 860px)/2)) 22px;border-top:1px solid var(--line);background:#0d0d20}
.composer textarea{flex:1;resize:none;max-height:200px;min-height:46px;padding:12px 14px}
.empty{margin:auto;text-align:center;color:var(--muted);max-width:520px}
.empty .big{font-size:26px;font-weight:800;color:var(--text);margin-bottom:6px;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.hints{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin-top:16px}
.hints button{background:var(--panel);border:1px solid var(--line);color:var(--text);border-radius:999px;padding:7px 14px;font-size:13px}
.hints button:hover{border-color:var(--violet)}
.page{flex:1;overflow-y:auto;padding:24px max(22px,calc((100% - 900px)/2));display:flex;flex-direction:column;gap:18px}
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:18px 20px}
.card-head{display:flex;align-items:baseline;gap:12px;flex-wrap:wrap;margin-bottom:12px}
.card-head h2{font-size:17px;margin:0}
.muted{color:var(--muted);font-size:13px}
.intro{margin:0}
.toggle{margin-left:auto;display:flex;gap:6px;align-items:center;cursor:pointer}
.inline-form{display:flex;gap:8px;margin-bottom:12px}
.inline-form input{flex:1}
.list{display:flex;flex-direction:column;gap:8px}
.item{display:flex;gap:12px;align-items:flex-start;background:var(--panel2);border:1px solid var(--line);border-radius:12px;padding:10px 14px}
.item .body{flex:1;min-width:0}
.item .meta{font-size:12px;color:var(--muted);margin-top:3px}
.item .actions{display:flex;gap:6px;flex:none}
.item.old{opacity:.55}
.item.old .text{text-decoration:line-through}
.tag{font-size:11px;padding:1px 8px;border-radius:999px;background:#a855f722;color:#e9d5ff;margin-right:6px;text-transform:capitalize}
.tag.src{background:#6366f122;color:#c7d2fe;text-transform:none}
.timeline{position:relative;padding-left:26px;display:flex;flex-direction:column;gap:14px}
.timeline::before{content:'';position:absolute;left:8px;top:6px;bottom:6px;width:2px;background:var(--line)}
.tl{position:relative;background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:12px 16px}
.tl::before{content:'';position:absolute;left:-23px;top:16px;width:12px;height:12px;border-radius:50%;background:var(--grad);box-shadow:0 0 0 3px var(--bg)}
.tl .when{font-size:12px;color:var(--muted)}
.tl .what{font-weight:600;margin:2px 0 6px}
.tl .old{color:#fca5a5;text-decoration:line-through}
.tl .new{color:#a7f3d0}
.tl .arrow{color:var(--muted);margin:0 6px}
.tl .why{font-size:13px;color:#ddd6fe;margin-top:6px}
.stats{display:flex;gap:12px}
.stat{flex:1;background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:14px 18px}
.stat .n{font-size:26px;font-weight:800}
.modal{position:fixed;inset:0;background:#000a;display:grid;place-items:center;z-index:10}
.modal[hidden]{display:none}
.modal-box{background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:20px;width:min(520px,92vw)}
.modal-box h3{margin:0 0 10px}
.modal-box textarea{width:100%}
.modal-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:12px}
.toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);background:#1e1b4b;border:1px solid var(--indigo);padding:10px 18px;border-radius:12px;z-index:20}
.toast[hidden]{display:none}
@media (max-width:820px){
  .sidebar{position:fixed;z-index:5;height:100%;transform:translateX(-100%);transition:.2s}
  .sidebar.open{transform:none}
  .menu-btn{display:block}
}