:root{
  --brand:#1a5fe0; --brand-dark:#0f3fa8; --ink:#0d1826; --muted:#5b6a82;
  --line:#e2e8f2; --soft:#f4f7fc; --bg:#fff; --danger:#c0362c;
}
*{box-sizing:border-box}
html,body{margin:0;height:100%}
body{font:14px/1.5 -apple-system,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;color:var(--ink);background:var(--soft)}
#app{height:100%}
button{font:inherit;cursor:pointer}
a{color:var(--brand)}

/* ---- login ---- */
.login{height:100%;display:flex;align-items:center;justify-content:center}
.login .card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:32px;width:360px;
  box-shadow:0 18px 50px rgba(13,24,38,.12)}
.login .mark{display:flex;align-items:center;gap:10px;margin-bottom:6px}
.login .mark b{font-size:17px}
.login p{color:var(--muted);margin:0 0 18px}
.login label{display:block;font-weight:600;font-size:13px;margin:10px 0 4px}
.login input{width:100%;border:1px solid var(--line);border-radius:10px;padding:10px 12px;font:inherit}
.login .go{width:100%;margin-top:18px;border:0;border-radius:10px;background:var(--brand);color:#fff;
  font-weight:700;padding:11px}
.login .err{color:var(--danger);font-size:13px;min-height:18px;margin-top:8px}

/* ---- shell ---- */
.shell{height:100%;display:grid;grid-template-rows:52px 1fr;grid-template-columns:230px 380px 1fr;
  grid-template-areas:"top top top" "nav list read"}
.top{grid-area:top;display:flex;align-items:center;gap:14px;padding:0 14px;background:var(--brand);color:#fff}
.top .logo{font-weight:700;letter-spacing:.2px}
.top .search{flex:1;max-width:520px}
.top .search input{width:100%;border:0;border-radius:999px;padding:8px 14px;font:inherit}
.top .who{font-size:13px;opacity:.9}
.top .who button{background:transparent;border:1px solid rgba(255,255,255,.4);color:#fff;border-radius:8px;padding:4px 10px;margin-left:8px}
.top .ai{background:#fff;color:var(--brand-dark);border:0;border-radius:999px;font-weight:700;padding:7px 14px}

.nav{grid-area:nav;background:#fff;border-right:1px solid var(--line);overflow-y:auto}
.nav h4{margin:14px 14px 6px;font-size:11px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.nav .mb{display:flex;align-items:center;gap:8px;padding:9px 14px;border:0;background:transparent;width:100%;text-align:left;color:var(--ink)}
.nav .mb:hover{background:var(--soft)}
.nav .mb.on{background:#e9f0ff;color:var(--brand-dark);font-weight:600}
.nav .mb .name{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.nav .mb .badge{background:var(--brand);color:#fff;border-radius:999px;font-size:11px;padding:1px 7px;min-width:18px;text-align:center}
.nav .mb.group .name{font-style:italic;color:var(--muted)}
.nav .folders{padding:2px 0 8px}
.nav .folders button{display:block;width:100%;text-align:left;border:0;background:transparent;padding:5px 14px 5px 30px;color:var(--muted)}
.nav .folders button.on{color:var(--brand-dark);font-weight:600}

.list{grid-area:list;background:#fff;border-right:1px solid var(--line);overflow-y:auto}
.list .lh{padding:10px 14px;border-bottom:1px solid var(--line);font-weight:700;position:sticky;top:0;background:#fff}
.list .lh small{font-weight:400;color:var(--muted)}
.list .msg{padding:10px 14px;border-bottom:1px solid var(--line);border-left:3px solid transparent}
.list .msg:hover{background:var(--soft)}
.list .msg.on{background:#e9f0ff;border-left-color:var(--brand)}
.list .msg.unread .subj{font-weight:700}
.list .msg .row1{display:flex;justify-content:space-between;gap:8px}
.list .msg .from{font-weight:600;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.list .msg .date{color:var(--muted);font-size:12px;flex:none}
.list .msg .subj{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.list .msg .prev{color:var(--muted);font-size:12.5px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.list .msg .mbtag{font-size:11px;color:var(--brand-dark);background:#e9f0ff;border-radius:6px;padding:0 5px}

.read{grid-area:read;overflow-y:auto;padding:20px 26px}
.read .empty{color:var(--muted);text-align:center;margin-top:80px}
.read h2{margin:0 0 6px;font-size:19px}
.read .meta{color:var(--muted);font-size:13px;border-bottom:1px solid var(--line);padding-bottom:12px;margin-bottom:16px}
.read .meta div{margin:2px 0}
.read .body{white-space:pre-wrap;word-wrap:break-word;font-size:14px}
.read .thread{margin-top:24px;border-top:1px solid var(--line);padding-top:12px}
.read .thread h5{margin:0 0 8px;color:var(--muted);text-transform:uppercase;font-size:11px;letter-spacing:.08em}
.read .thread .ti{padding:6px 0;border-bottom:1px solid var(--line);font-size:13px}
.read .att{margin-top:14px;font-size:13px;color:var(--muted)}
.badge-ro{display:inline-block;font-size:11px;background:var(--soft);border:1px solid var(--line);border-radius:6px;padding:1px 6px;color:var(--muted);margin-left:8px}

/* ---- chat drawer ---- */
.chat{position:fixed;top:0;right:0;height:100%;width:420px;max-width:100vw;background:#fff;
  border-left:1px solid var(--line);box-shadow:-12px 0 40px rgba(13,24,38,.14);display:flex;flex-direction:column;z-index:50;transform:translateX(100%);transition:transform .18s ease}
.chat.open{transform:none}
.chat .ch{display:flex;align-items:center;gap:8px;padding:12px 14px;border-bottom:1px solid var(--line);background:var(--soft)}
.chat .ch b{flex:1}
.chat .ch button{border:0;background:transparent;font-size:20px;color:var(--muted)}
.chat .log{flex:1;overflow-y:auto;padding:14px}
.chat .m{margin-bottom:12px;display:flex}
.chat .m .b{max-width:86%;padding:9px 12px;border-radius:12px;white-space:pre-wrap;word-wrap:break-word}
.chat .m.user{justify-content:flex-end}
.chat .m.user .b{background:var(--brand);color:#fff;border-bottom-right-radius:4px}
.chat .m.bot .b{background:var(--soft);border:1px solid var(--line);border-bottom-left-radius:4px}
.chat .m.tool .b{background:#fff;border:1px dashed var(--line);color:var(--muted);font-size:12px}
.chat .foot{border-top:1px solid var(--line);padding:10px;display:flex;gap:8px}
.chat .foot textarea{flex:1;resize:none;border:1px solid var(--line);border-radius:10px;padding:9px 11px;font:inherit;min-height:40px;max-height:120px}
.chat .foot button{border:0;border-radius:10px;background:var(--brand);color:#fff;font-weight:700;padding:0 16px}
.chat .hint{padding:0 14px 10px;display:flex;flex-wrap:wrap;gap:6px}
.chat .hint button{font-size:12px;border:1px solid var(--line);background:#fff;border-radius:999px;padding:5px 10px;color:var(--brand-dark)}
.mk{width:34px;height:34px;border-radius:9px;background:linear-gradient(135deg,#1a5fe0,#0f3fa8);flex:none}