:root{
  --bg:#F6F7F9; --surface:#FFFFFF; --surface-2:#EEF0F4; --sunken:#F1F2F6;
  --ink:#1A1C22; --muted:#6B7180; --faint:#9AA0AD;
  --accent:#0E8577; --accent-ink:#0A5F55; --accent-soft:#DFF0EC;
  --add:#2E7D5B; --add-soft:#E4F3EB; --del:#C0453B; --del-soft:#FBE9E7;
  --ring:0 0 0 3px rgba(14,133,119,.18);
  --shadow-sm:0 1px 2px rgba(20,22,30,.05);
  --shadow:0 6px 22px rgba(20,22,30,.09);
  --shadow-rail:8px 0 24px -18px rgba(20,22,30,.28);
  --shadow-ai:-14px 0 34px -20px rgba(20,22,30,.30);
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
  --ui:"Hanken Grotesk",system-ui,-apple-system,sans-serif;
  --brand:"Bricolage Grotesque",var(--ui);
  --serif:"Newsreader",Georgia,serif;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#0F1115; --surface:#181B21; --surface-2:#20242C; --sunken:#14171C;
  --ink:#E8EAF0; --muted:#9AA0AD; --faint:#646A76;
  --accent:#3FB6A8; --accent-ink:#6FD3C7; --accent-soft:#16332E;
  --add:#4FB07E; --add-soft:#152C1D; --del:#D97369; --del-soft:#311A17;
  --ring:0 0 0 3px rgba(63,182,168,.22);
  --shadow-sm:0 1px 2px rgba(0,0,0,.4);
  --shadow:0 8px 28px rgba(0,0,0,.45);
  --shadow-rail:8px 0 24px -18px rgba(0,0,0,.6);
  --shadow-ai:-14px 0 34px -20px rgba(0,0,0,.6);
}}
:root[data-theme="dark"]{
  --bg:#0F1115; --surface:#181B21; --surface-2:#20242C; --sunken:#14171C;
  --ink:#E8EAF0; --muted:#9AA0AD; --faint:#646A76;
  --accent:#3FB6A8; --accent-ink:#6FD3C7; --accent-soft:#16332E;
  --add:#4FB07E; --add-soft:#152C1D; --del:#D97369; --del-soft:#311A17;
  --ring:0 0 0 3px rgba(63,182,168,.22);
  --shadow-sm:0 1px 2px rgba(0,0,0,.4);
  --shadow:0 8px 28px rgba(0,0,0,.45);
  --shadow-rail:8px 0 24px -18px rgba(0,0,0,.6);
  --shadow-ai:-14px 0 34px -20px rgba(0,0,0,.6);
}
*{box-sizing:border-box}
html,body{height:100%}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--ui);font-size:14px;
  line-height:1.5;-webkit-font-smoothing:antialiased;overflow:hidden}
button{font-family:inherit;cursor:pointer;color:inherit;border:none;background:none}
:focus-visible{outline:none;box-shadow:var(--ring);border-radius:8px}

.app{display:grid;grid-template-columns:240px 1fr;grid-template-rows:54px 1fr;height:100vh}

/* top — no border, soft shadow float */
.top{grid-column:1/3;display:flex;align-items:center;gap:14px;padding:0 18px;background:var(--surface);
  box-shadow:var(--shadow-sm);z-index:6;position:relative}
.brand{display:flex;align-items:center;gap:9px;font-family:var(--brand);font-weight:700;font-size:17px;
  letter-spacing:-.015em;width:208px;flex:none}
.brand .mark{width:23px;height:23px;border-radius:7px;background:var(--accent);display:grid;place-items:center;
  color:#fff;font-size:13px;flex:none}
:root[data-theme="dark"] .brand .mark,:root:not([data-theme="light"]) .brand .mark{color:#08120f}
.doctitle{font-weight:600;font-size:14.5px;letter-spacing:-.01em;color:var(--ink)}
.status{font-size:12px;color:var(--muted);display:flex;align-items:center;gap:7px}
.dot{width:6px;height:6px;border-radius:50%;background:var(--faint);transition:background .2s}
.dot.saved{background:var(--add)}
.spacer{flex:1}
.tbtn{background:var(--surface-2);border-radius:9px;padding:8px 13px;font-size:13px;font-weight:600;
  display:inline-flex;align-items:center;gap:7px;transition:filter .15s,transform .05s}
.tbtn:hover{filter:brightness(.97)}.tbtn:active{transform:translateY(1px)}
.tbtn.primary{background:var(--accent);color:#fff}
:root[data-theme="dark"] .tbtn.primary,:root:not([data-theme="light"]) .tbtn.primary{color:#08120f}
.icobtn{width:36px;height:36px;border-radius:9px;display:grid;place-items:center;color:var(--muted);
  background:var(--surface-2);transition:filter .15s,color .15s}
.icobtn:hover{color:var(--ink);filter:brightness(.97)}

/* rail — surface tone + float shadow, no border */
.rail{background:var(--surface);box-shadow:var(--shadow-rail);display:flex;flex-direction:column;
  overflow:hidden;z-index:3}
.rail-h{font-size:11px;font-weight:700;letter-spacing:.09em;text-transform:uppercase;color:var(--faint);
  padding:16px 18px 7px}
.doclist{padding:0 10px 6px}
.doclist:last-of-type{flex:1;overflow-y:auto}
.doc{width:100%;text-align:left;border-radius:9px;padding:9px 11px;display:flex;flex-direction:column;gap:2px;
  margin-bottom:1px;transition:background .12s}
.doc:hover{background:var(--surface-2)}
.doc.active{background:var(--accent-soft)}
.doc .n{font-size:13.5px;font-weight:500;color:var(--ink);letter-spacing:-.005em}
.doc.active .n{color:var(--accent-ink)}
.doc .m{font-size:11.5px;color:var(--muted);font-variant-numeric:tabular-nums}
.rail-f{margin-top:auto;padding:13px 18px;font-size:11.5px;color:var(--muted);display:flex;align-items:center;gap:8px;
  background:var(--sunken)}
.rail-f .g{width:14px;height:14px;flex:none}

/* work area — panes separated by background tone, never lines */
.work{display:grid;grid-template-columns:1fr 1fr;min-width:0;overflow:hidden;position:relative;background:var(--bg)}
.pane{display:flex;flex-direction:column;min-width:0;overflow:hidden}
.pane-editor{background:var(--surface)}
.pane-preview{background:var(--bg)}
.pane-h{display:flex;align-items:center;gap:8px;padding:0 18px;height:40px;font-size:11px;font-weight:700;
  letter-spacing:.09em;text-transform:uppercase;color:var(--faint)}
.pane-h .r{margin-left:auto;font-weight:500;letter-spacing:0;text-transform:none;font-size:12px;color:var(--muted);
  font-variant-numeric:tabular-nums}
.cm-wrap{flex:1;overflow:hidden}
.CodeMirror{height:100%;background:var(--surface);color:var(--ink);
  font-family:var(--mono);font-size:13px;line-height:1.7;padding:8px 6px}
.CodeMirror-gutters{background:var(--surface);border:none}
.CodeMirror-cursor{border-left:1.5px solid var(--accent)}
.CodeMirror-selected{background:var(--accent-soft)!important}
.cm-header{color:var(--accent-ink);font-weight:600}
.cm-quote{color:var(--muted)}
.cm-link,.cm-url{color:var(--accent-ink)}

.preview{flex:1;overflow-y:auto;padding:28px 32px}
.preview-slides{flex:1;width:100%;border:none;background:transparent}
.doc-body{max-width:64ch;font-family:var(--serif);font-size:16px;line-height:1.68;color:var(--ink)}
.doc-body h1{font-family:var(--ui);font-weight:700;font-size:27px;line-height:1.18;letter-spacing:-.02em;margin:0 0 .5em;text-wrap:balance}
.doc-body h2{font-family:var(--ui);font-weight:700;font-size:19px;letter-spacing:-.01em;margin:1.6em 0 .5em;text-wrap:balance}
.doc-body h3{font-family:var(--ui);font-weight:600;font-size:15.5px;margin:1.4em 0 .4em}
.doc-body p{margin:0 0 1em}
.doc-body ul,.doc-body ol{margin:0 0 1em;padding-left:1.3em}
.doc-body li{margin:.3em 0}
.doc-body code{font-family:var(--mono);font-size:.85em;background:var(--surface-2);padding:.12em .38em;border-radius:5px}
.doc-body pre{background:var(--surface-2);border-radius:11px;padding:14px 16px;overflow-x:auto;margin:0 0 1em}
.doc-body pre code{background:none;padding:0}
.doc-body blockquote{margin:0 0 1em;padding:.2em 0 .2em 1em;box-shadow:inset 3px 0 0 var(--surface-2);color:var(--muted)}
.doc-body hr{border:none;height:1px;background:var(--surface-2);margin:1.6em 0}
.doc-body a{color:var(--accent-ink);text-decoration:underline;text-underline-offset:2px}

/* AI panel — floats over preview, shadow not border */
.ai{position:absolute;right:0;top:0;bottom:0;width:0;background:var(--surface);box-shadow:var(--shadow-ai);
  display:flex;flex-direction:column;overflow:hidden;transition:width .22s cubic-bezier(.4,0,.2,1);z-index:4}
.ai.open{width:384px}
.ai-h{display:flex;align-items:center;gap:8px;padding:14px 16px;flex:none}
.ai-h .t{font-family:var(--brand);font-weight:700;font-size:14.5px}
.ai-h .badge{font-size:10px;font-family:var(--mono);color:var(--accent-ink);background:var(--accent-soft);padding:2px 6px;border-radius:6px}
.ai-h .x{margin-left:auto;width:30px;height:30px}
.ai-body{flex:1;overflow-y:auto;padding:6px 16px 16px;display:flex;flex-direction:column;gap:12px}
.scope{display:flex;gap:6px;background:var(--surface-2);padding:3px;border-radius:10px}
.scope button{flex:1;font-size:12px;padding:7px;border-radius:8px;color:var(--muted);font-weight:600;transition:.15s}
.scope button.on{background:var(--surface);color:var(--accent-ink);box-shadow:var(--shadow-sm)}
.prompt{width:100%;background:var(--surface-2);color:var(--ink);font-family:var(--ui);font-size:13.5px;line-height:1.5;
  padding:12px 13px;border-radius:11px;resize:vertical;min-height:78px;border:none;outline:none;transition:box-shadow .15s}
.prompt:focus{box-shadow:var(--ring)}
.chips{display:flex;flex-wrap:wrap;gap:6px}
.chip{font-size:11.5px;padding:6px 10px;border-radius:20px;background:var(--surface-2);color:var(--muted);transition:.15s}
.chip:hover{color:var(--accent-ink);filter:brightness(.97)}
.run{width:100%;background:var(--accent);color:#fff;border-radius:11px;padding:12px;font-size:13.5px;font-weight:700;
  display:flex;align-items:center;justify-content:center;gap:8px;transition:filter .15s}
:root[data-theme="dark"] .run,:root:not([data-theme="light"]) .run{color:#08120f}
.run:hover{filter:brightness(1.05)}.run:disabled{opacity:.55;cursor:default}
.hint{font-size:11.5px;color:var(--faint);line-height:1.45;margin:0}
.hint code{font-family:var(--mono);font-size:.95em}

.diff{border-radius:12px;overflow:hidden;background:var(--sunken);box-shadow:var(--shadow-sm)}
.diff-h{display:flex;align-items:center;gap:8px;padding:10px 13px;font-size:12px;font-weight:700;background:var(--surface-2)}
.diff-h .meta{margin-left:auto;font-family:var(--mono);font-size:11px;font-weight:400;color:var(--muted)}
.diff-body{max-height:240px;overflow:auto;font-family:var(--mono);font-size:11.5px;line-height:1.55;padding:4px 0}
.dl{display:flex;padding:1px 10px 1px 0;white-space:pre-wrap;word-break:break-word}
.dl .s{width:22px;flex:none;text-align:center;color:var(--faint);user-select:none}
.dl.add{background:var(--add-soft)}.dl.add .s,.dl.add .c{color:var(--add)}
.dl.del{background:var(--del-soft)}.dl.del .s{color:var(--del)}.dl.del .c{color:var(--del);text-decoration:line-through;opacity:.75}
.dl.ctx{color:var(--muted)}.dl.gap{color:var(--faint);font-style:italic;opacity:.7}
.diff-actions{display:flex;gap:8px;padding:11px 13px}
.diff-actions .accept{flex:1;background:var(--add);color:#fff;border-radius:9px;padding:10px;font-weight:700;font-size:13px}
:root[data-theme="dark"] .diff-actions .accept,:root:not([data-theme="light"]) .diff-actions .accept{color:#06130c}
.diff-actions .ghost{background:var(--surface-2);border-radius:9px;padding:10px 14px;font-size:13px;font-weight:600;color:var(--muted)}
.diff-actions .ghost:hover{color:var(--ink);filter:brightness(.97)}
.thinking{display:flex;align-items:center;gap:9px;color:var(--muted);font-size:12.5px;padding:4px 2px}
.thinking code{font-family:var(--mono)}
.spin{width:14px;height:14px;border-radius:50%;border:2px solid var(--surface-2);border-top-color:var(--accent);animation:sp .7s linear infinite}
@keyframes sp{to{transform:rotate(360deg)}}
@media (prefers-reduced-motion:reduce){.spin{animation:none}.ai{transition:none}}

.toast{position:fixed;bottom:22px;left:50%;transform:translateX(-50%) translateY(18px);background:var(--ink);color:var(--bg);
  padding:11px 17px;border-radius:11px;font-size:13px;font-weight:600;display:flex;align-items:center;gap:9px;
  box-shadow:var(--shadow);opacity:0;pointer-events:none;transition:opacity .2s,transform .2s;z-index:20}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
.toast .tk{color:var(--add)}

/* auth */
.user{display:flex;align-items:center;gap:9px;font-size:12.5px;color:var(--muted)}
.user .uname{font-weight:600;color:var(--ink)}
.logout{background:var(--surface-2);border-radius:8px;padding:7px 11px;font-size:12.5px;font-weight:600;color:var(--muted);transition:filter .15s,color .15s}
.logout:hover{color:var(--ink);filter:brightness(.97)}
.login{position:fixed;inset:0;z-index:50;display:flex;overflow-y:auto;background:var(--bg);padding:24px 16px}
.login-card{margin:auto;width:342px;max-width:100%;background:var(--surface);border-radius:16px;box-shadow:var(--shadow);padding:32px 28px;display:flex;flex-direction:column;gap:12px}
.login-brand{font-family:var(--brand);font-weight:700;font-size:22px;letter-spacing:-.015em;display:flex;align-items:center;gap:10px}
.login-brand .mark{width:27px;height:27px;border-radius:8px;background:var(--accent);color:#fff;display:grid;place-items:center;font-size:14px}
.login-sub{margin:0 0 8px;color:var(--muted);font-size:13px}
.login-in{width:100%;background:var(--surface-2);border:none;border-radius:10px;padding:12px 13px;font-family:var(--ui);font-size:14px;color:var(--ink);outline:none;transition:box-shadow .15s}
.login-in:focus{box-shadow:var(--ring)}
.login-btn{margin-top:4px;width:100%;background:var(--accent);color:#fff;border-radius:10px;padding:12px;font-weight:700;font-size:14px;transition:filter .15s}
.login-btn:hover{filter:brightness(1.05)}
.login-err{margin:2px 0 0;color:var(--del);font-size:12.5px;font-weight:500}
:root[data-theme="dark"] .login-brand .mark,:root:not([data-theme="light"]) .login-brand .mark,
:root[data-theme="dark"] .login-btn,:root:not([data-theme="light"]) .login-btn{color:#08120f}

@media (max-width:900px){
  .app{grid-template-columns:1fr}.rail{display:none}
  .work{grid-template-columns:1fr}.pane-preview{display:none}.ai.open{width:100%}
}