:root{
  --bg:#ffffff; --side:#f7f7f8; --ink:#2d333a; --muted:#8e8ea0; --line:#e6e6ea;
  --acc:#10a37f; --acc2:#0d8c6d; --user:#f0f4f9; --asst:#ffffff; --chip:#eef7f3;
}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,Segoe UI,Roboto,Helvetica,sans-serif;color:var(--ink);background:var(--bg)}

/* ---------- 3-column app ---------- */
.app{display:grid;grid-template-columns:248px 1fr 290px;height:100vh}
.sidebar{background:var(--side);border-right:1px solid var(--line);display:flex;flex-direction:column;padding:12px}
.newchat{background:#fff;border:1px solid var(--line);border-radius:10px;padding:10px;font-weight:600;cursor:pointer;font-size:14px}
.newchat:hover{background:#fbfbfc}
.sessions{flex:1;overflow:auto;margin-top:12px;display:flex;flex-direction:column;gap:4px}
.sess{padding:9px 10px;border-radius:8px;font-size:13px;color:var(--ink);cursor:pointer;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.sess:hover{background:#ececf1}.sess.on{background:#e3efe9}
.sidefoot{border-top:1px solid var(--line);padding-top:10px;font-size:12px;color:var(--muted);display:flex;flex-direction:column;gap:6px}
.sidefoot a{color:var(--acc);text-decoration:none}.sidefoot .model{font-weight:600;color:var(--ink)}

/* ---------- center chat ---------- */
.chat{display:flex;flex-direction:column;min-width:0}
.chathead{padding:14px 22px;border-bottom:1px solid var(--line);font-weight:600;font-size:15px}
.chathead .dot{display:inline-block;width:8px;height:8px;border-radius:50%;background:var(--acc);margin-right:7px}
.chathead small{color:var(--muted);font-weight:400;font-size:12px;margin-left:8px}
.thread{flex:1;overflow:auto;padding:22px 0}
.empty{max-width:620px;margin:60px auto;text-align:center;color:var(--muted);font-size:15px;line-height:1.6;padding:0 20px}
.msg{padding:6px 0}
.msg .bubble{max-width:720px;margin:0 auto;padding:4px 22px;line-height:1.6;font-size:15px;white-space:pre-wrap}
.msg.user .bubble{background:var(--user);border-radius:12px;padding:12px 16px;max-width:680px}
.msg.user{display:flex;justify-content:center}
.msg.assistant .bubble{color:var(--ink)}
.composer{border-top:1px solid var(--line);padding:14px 22px;display:flex;gap:10px;align-items:flex-end;max-width:780px;margin:0 auto;width:100%}
.composer textarea{flex:1;resize:none;border:1px solid var(--line);border-radius:12px;padding:12px 14px;font-size:15px;font-family:inherit;max-height:160px;outline:none}
.composer textarea:focus{border-color:var(--acc)}
.send,.stop{border:0;border-radius:10px;padding:11px 18px;font-weight:600;cursor:pointer;font-size:14px}
.send{background:var(--acc);color:#fff}.send:hover{background:var(--acc2)}
.stop{background:#ef4444;color:#fff}

/* ---------- right controls ---------- */
.controls{background:var(--side);border-left:1px solid var(--line);padding:18px 16px;overflow:auto}
.controls h3{font-size:12px;text-transform:uppercase;letter-spacing:.5px;color:var(--muted);margin:18px 0 10px}
.controls h3:first-child{margin-top:0}
.controls label{display:block;font-size:13px;font-weight:600;margin:12px 0 5px}
.controls .muted{color:var(--muted);font-weight:400}
.controls select{width:100%;background:#fff;border:1px solid var(--line);border-radius:9px;padding:9px;font-size:14px}
.controls input[type=range]{width:100%;accent-color:var(--acc)}
.controls output{color:var(--acc);font-weight:700;float:right}
.switch{display:flex;align-items:center;gap:8px;font-size:13px;font-weight:600;margin-top:14px}
.timers{display:flex;flex-direction:column;gap:8px}
.timers .t{display:flex;justify-content:space-between;align-items:center;background:#fff;border:1px solid var(--line);border-radius:9px;padding:9px 11px;font-size:13px;color:var(--muted)}
.timers .t b{color:var(--ink);font-size:15px}
.timers .t.big b{color:var(--acc);font-size:20px}
.note{margin-top:12px;font-size:12px;color:var(--muted);line-height:1.5}
.chip{display:inline-block;margin-top:8px;font-size:11px;padding:3px 9px;border-radius:20px;background:var(--chip);color:var(--acc)}
.chip.bad{background:#fdecec;color:#d33}

/* ---------- login ---------- */
.login-bg{display:flex;align-items:center;justify-content:center;min-height:100vh;background:#f7f7f8}
.login-card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:34px;width:360px;box-shadow:0 4px 24px rgba(0,0,0,.04)}
.login-card h1{margin:0 0 4px;font-size:22px}.login-card .sub{color:var(--muted);font-size:13px;margin:0 0 22px}
.login-card label{display:block;font-size:13px;font-weight:600;margin-top:12px}
.login-card input{width:100%;border:1px solid var(--line);border-radius:9px;padding:11px;margin-top:5px;font-size:14px;outline:none}
.login-card input:focus{border-color:var(--acc)}
.login-card button{margin-top:20px;width:100%;background:var(--acc);color:#fff;border:0;border-radius:10px;padding:12px;font-weight:600;cursor:pointer}
.login-card .hint{font-size:11px;color:var(--muted);margin-top:16px;text-align:center}
.error{background:#fdecec;color:#d33;border:1px solid #f5c2c2;padding:9px;border-radius:8px;font-size:13px;margin-bottom:8px}

/* ---------- admin (light) ---------- */
header{display:flex;justify-content:space-between;align-items:center;padding:14px 22px;background:#fff;border-bottom:1px solid var(--line)}
header .brand{font-weight:700}header .who{display:flex;gap:16px;font-size:13px;color:var(--muted);align-items:center}
header .who a{color:var(--acc);text-decoration:none}
main.adminmain,main{max-width:1000px;margin:22px auto;padding:0 18px}
.panel{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px 20px;margin-bottom:18px}
.panel h2{font-size:14px;color:var(--muted);margin:0 0 14px}
.tbl{width:100%;border-collapse:collapse;font-size:13px}
.tbl th,.tbl td{text-align:left;padding:7px 9px;border-bottom:1px solid var(--line)}
.tbl th{color:var(--muted)}
.userform{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:14px}
.userform input,.userform select{border:1px solid var(--line);border-radius:8px;padding:9px;flex:1;min-width:140px}
.userform button{background:var(--acc);color:#fff;border:0;border-radius:8px;padding:9px 16px;cursor:pointer}
.a-login{color:var(--acc)}.a-generate{color:#2b6cb0}.a-logout{color:var(--muted)}.a-add_user{color:#b7791f}
.muted{color:var(--muted)}