:root { --bg:#f6f4ef; --card:#fff; --ink:#1d1d1b; --muted:#77736b; --accent:#1f6f5c; --in:#fff; --out:#e3f1ec;
  --line:#e2ded6; --err:#b3261e; }
@media (prefers-color-scheme: dark) { :root { --bg:#151714; --card:#1f221f; --ink:#ecebe6; --muted:#9a978f;
  --accent:#5fb89f; --in:#232723; --out:#1d3a32; --line:#33372f; --err:#f2b8b5; } }
* { box-sizing:border-box; }
html, body { margin:0; height:100%; background:var(--bg); color:var(--ink);
  font:16px/1.4 -apple-system, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif; }
button, select, input, textarea { font:inherit; color:inherit; }
button { border:0; border-radius:10px; padding:10px 14px; background:var(--accent); color:#fff; cursor:pointer; }
button.secondary, .pill { background:var(--card); color:var(--ink); border:1px solid var(--line); }
button:disabled { opacity:.5; }
#login[hidden], #app[hidden] { display:none; }
#login { display:grid; place-items:center; min-height:100%; padding:16px; }
.card { background:var(--card); padding:24px; border-radius:16px; width:min(360px,100%); display:grid; gap:12px; }
.card h1 { margin:0 0 4px; font-size:22px; }
input, textarea, select { background:var(--card); border:1px solid var(--line); border-radius:10px; padding:10px; width:100%; }
#app { display:flex; flex-direction:column; height:100dvh; max-width:760px; margin:0 auto; }
header { position:relative; display:flex; gap:8px; align-items:center; padding:10px 12px;
  padding-top:max(10px, env(safe-area-inset-top)); border-bottom:1px solid var(--line); }
header select { flex:1; min-width:0; }
.toggles { display:flex; gap:6px; }
.pill { padding:8px 10px; border-radius:999px; white-space:nowrap; }
.menu[hidden] { display:none; }
.menu { position:absolute; right:12px; top:100%; z-index:5; background:var(--card); border:1px solid var(--line);
  border-radius:12px; display:grid; padding:6px; min-width:200px; box-shadow:0 8px 24px rgba(0,0,0,.15); }
.menu button, .menu a { background:none; color:var(--ink); text-align:left; padding:10px; text-decoration:none; border-radius:8px; }
.menu button:hover, .menu a:hover { background:var(--bg); }
#feed { flex:1; overflow-y:auto; padding:12px; display:flex; flex-direction:column; gap:10px; }
.msg { max-width:88%; padding:10px 12px; border-radius:14px; border:1px solid var(--line); position:relative; }
.msg.in { align-self:flex-start; background:var(--in); }
.msg.out { align-self:flex-end; background:var(--out); }
.msg .src { color:var(--muted); font-size:14px; white-space:pre-wrap; }
.msg .dst { font-size:17px; white-space:pre-wrap; margin-top:4px; }
.msg .back { color:var(--muted); font-size:13px; margin-top:6px; }
.msg .tools { display:flex; gap:6px; margin-top:6px; justify-content:flex-end; }
.msg .tools button { background:none; color:var(--muted); padding:4px 8px; font-size:13px; border:1px solid var(--line); }
.empty { color:var(--muted); text-align:center; margin:auto; max-width:300px; }
.pending { opacity:.6; }
footer { border-top:1px solid var(--line); padding:10px 12px; padding-bottom:max(10px, env(safe-area-inset-bottom));
  display:grid; gap:8px; }
footer textarea { resize:none; max-height:40vh; }
.actions { display:flex; gap:8px; }
.actions button { flex:1; }
.err, .err-bar { color:var(--err); }
.err-bar { display:flex; gap:8px; align-items:center; justify-content:space-between; padding:8px 12px; }
.err-bar[hidden] { display:none; }
#toast { position:fixed; left:50%; bottom:110px; transform:translateX(-50%); background:var(--ink); color:var(--bg);
  padding:8px 14px; border-radius:999px; font-size:14px; z-index:10; }
.help { max-width:680px; margin:0 auto; padding:16px; }
.help h2 { margin-top:28px; }
.help ol li { margin:6px 0; }