:root {
  --blue: #4d6bfe;
  --blue-dark: #3a56e8;
  --blue-soft: #e8edff;
  --bg: #ffffff;
  --side: #f9fafb;
  --hover: #eef0f5;
  --text: #1a1d29;
  --muted: #6b7185;
  --border: #e5e7ee;
  --user-bubble: #eff6ff;
  --code-bg: #f6f8fa;
  --code-head: #eceff3;
  color-scheme: light;
}
[data-theme="dark"] {
  --blue: #6b84ff;
  --blue-dark: #5a74f5;
  --blue-soft: #232a4a;
  --bg: #16171d;
  --side: #1d1e26;
  --hover: #2a2c37;
  --text: #ececf1;
  --muted: #9a9fb2;
  --border: #2d2f3b;
  --user-bubble: #262a3d;
  --code-bg: #0f1015;
  --code-head: #23252f;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0; overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  font-size: 16px; line-height: 1.65; color: var(--text); background: var(--bg);
}
button { font: inherit; color: inherit; }
a { color: var(--blue); }
svg { flex-shrink: 0; }

.app { display: flex; height: 100vh; height: 100dvh; }

/* sidebar */
.sidebar {
  width: 272px; flex-shrink: 0; background: var(--side); border-inline-end: 1px solid var(--border);
  display: flex; flex-direction: column; padding: 14px 12px; gap: 10px; z-index: 30;
  transition: margin-inline-start .2s ease, transform .2s ease;
}
.app.sb-closed .sidebar { margin-inline-start: -272px; }
.sb-top { display: flex; align-items: center; justify-content: space-between; padding: 2px 4px 6px; }
.brand { display: flex; align-items: center; gap: 9px; font-weight: 700; font-size: 19px; color: var(--text); text-decoration: none; }
.brand img { width: 28px; height: 28px; border-radius: 7px; }
.ibtn {
  width: 36px; height: 36px; border: 0; border-radius: 10px; background: transparent; cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center; color: var(--muted);
}
.ibtn:hover { background: var(--hover); color: var(--text); }
.ibtn svg { width: 20px; height: 20px; }
[dir="rtl"] #closeSb svg, [dir="rtl"] #openSb svg { transform: scaleX(-1); }
.new-chat {
  display: flex; align-items: center; justify-content: center; gap: 8px; height: 42px; border-radius: 12px;
  border: 1px solid var(--border); background: var(--bg); color: var(--blue); font-weight: 600; cursor: pointer;
}
.new-chat:hover { background: var(--blue-soft); border-color: transparent; }
.new-chat svg { width: 18px; height: 18px; }
.sb-search {
  height: 38px; border-radius: 10px; border: 1px solid var(--border); background: var(--bg); color: var(--text);
  padding: 0 12px; font: inherit; font-size: 14px; outline: 0;
}
.sb-search:focus { border-color: var(--blue); }
.history { flex: 1; overflow-y: auto; margin: 0 -4px; padding: 0 4px; }
.history-group { font-size: 12px; font-weight: 600; color: var(--muted); padding: 14px 10px 6px; }
.history-item {
  display: flex; align-items: center; gap: 6px; padding: 8px 10px; border-radius: 10px; cursor: pointer; font-size: 14px;
}
.history-item:hover { background: var(--hover); }
.history-item.active { background: var(--blue-soft); }
.history-item span { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.history-item .del { opacity: 0; width: 26px; height: 26px; border-radius: 6px; }
.history-item:hover .del, .history-item.active .del { opacity: 1; }
.history-item .del svg { width: 15px; height: 15px; }
.history-empty { color: var(--muted); font-size: 13px; padding: 14px 10px; }
.sb-bottom { border-top: 1px solid var(--border); padding-top: 10px; display: flex; flex-direction: column; gap: 4px; }
.sb-link {
  display: flex; align-items: center; gap: 10px; padding: 8px 10px; border-radius: 10px; font-size: 14px;
  color: var(--text); text-decoration: none; background: none; border: 0; cursor: pointer; text-align: start; width: 100%;
}
.sb-link:hover { background: var(--hover); }
.sb-link svg { width: 18px; height: 18px; color: var(--muted); }
.quota { font-size: 13px; color: var(--muted); padding: 4px 10px 0; }
.lang-select {
  margin: 4px 0 2px; height: 34px; border-radius: 10px; border: 1px solid var(--border); background: var(--bg); color: var(--text);
  padding: 0 8px; font: inherit; font-size: 14px; cursor: pointer;
}
.scrim { display: none; }

/* main */
.main { flex: 1; min-width: 0; display: flex; flex-direction: column; position: relative; }
.topbar { height: 56px; display: flex; align-items: center; gap: 6px; padding: 0 12px; flex-shrink: 0; }
.topbar .title { flex: 1; min-width: 0; text-align: center; font-weight: 600; font-size: 15px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.app:not(.sb-closed) .topbar .open-sb { visibility: hidden; }

.scroller { flex: 1; overflow-y: auto; overflow-x: hidden; overscroll-behavior: contain; }
.thread { max-width: 800px; margin: 0 auto; padding: 8px 20px 24px; }

.welcome { max-width: 800px; margin: 0 auto; padding: 12vh 20px 20px; text-align: center; }
.welcome-title { display: flex; align-items: center; justify-content: center; gap: 12px; margin: 0 0 8px; font-size: 26px; font-weight: 700; }
.welcome-title img { width: 44px; height: 44px; border-radius: 12px; }
.welcome p { color: var(--muted); margin: 0 0 28px; }
.suggest { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; max-width: 640px; margin: 0 auto; }
.suggest button {
  text-align: start; padding: 12px 14px; border-radius: 14px; border: 1px solid var(--border); background: var(--bg);
  cursor: pointer; font-size: 14px; line-height: 1.45;
}
.suggest button:hover { border-color: var(--blue); background: var(--blue-soft); }
.suggest b { display: block; font-weight: 600; margin-bottom: 2px; }
.suggest small { color: var(--muted); font-size: 13px; }
.has-messages .welcome { display: none; }

/* messages */
.msg { margin: 22px 0; }
.msg.user { display: flex; flex-direction: column; align-items: flex-end; }
.msg.user .bubble {
  background: var(--user-bubble); padding: 10px 16px; border-radius: 20px; max-width: 85%;
  white-space: pre-wrap; word-wrap: break-word; overflow-wrap: anywhere;
}
.msg.ai { display: flex; gap: 14px; }
.msg.ai .avatar { width: 30px; height: 30px; border-radius: 50%; border: 1px solid var(--border); padding: 4px; flex-shrink: 0; background: var(--bg); }
.msg.ai .body { flex: 1; min-width: 0; }
.answer { overflow-wrap: anywhere; }
.answer > :first-child { margin-top: 2px; }
.answer > :last-child { margin-bottom: 0; }
.answer p { margin: 0 0 12px; }
.answer h1, .answer h2, .answer h3, .answer h4 { line-height: 1.3; margin: 20px 0 10px; }
.answer h1 { font-size: 1.45em; } .answer h2 { font-size: 1.3em; } .answer h3 { font-size: 1.15em; } .answer h4 { font-size: 1em; }
.answer ul, .answer ol { padding-inline-start: 24px; margin: 0 0 12px; }
.answer li { margin: 4px 0; }
.answer blockquote { margin: 0 0 12px; padding: 2px 14px; border-inline-start: 3px solid var(--border); color: var(--muted); }
.answer hr { border: 0; border-top: 1px solid var(--border); margin: 18px 0; }
.answer a { text-decoration: underline; }
.answer :not(pre) > code { background: var(--code-bg); border: 1px solid var(--border); border-radius: 6px; padding: 1px 5px; font-size: .88em; }
.answer img { max-width: 100%; border-radius: 12px; }
.tbl { overflow-x: auto; margin: 0 0 12px; }
.tbl table { border-collapse: collapse; font-size: 14.5px; min-width: 50%; }
.tbl th, .tbl td { border: 1px solid var(--border); padding: 7px 12px; text-align: start; vertical-align: top; }
.tbl th { background: var(--code-bg); font-weight: 600; }
.code { border: 1px solid var(--border); border-radius: 12px; overflow: hidden; margin: 0 0 14px; background: var(--code-bg); }
.code-head { display: flex; align-items: center; justify-content: space-between; padding-block: 6px; padding-inline: 14px 8px; background: var(--code-head); font-size: 12.5px; color: var(--muted); }
.code-copy { display: inline-flex; align-items: center; gap: 6px; border: 0; background: transparent; cursor: pointer; color: var(--muted); font-size: 12.5px; padding: 3px 8px; border-radius: 6px; }
.code-copy:hover { background: var(--hover); color: var(--text); }
.code-copy svg { width: 14px; height: 14px; }
.code pre { direction: ltr; text-align: left; margin: 0; padding: 14px; overflow-x: auto; font-size: 13.5px; line-height: 1.55; background: transparent !important; }
.code code { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace; text-shadow: none !important; }
.token.comment, .token.prolog, .token.doctype, .token.cdata { color: #6a737d; font-style: italic; }
.token.punctuation { color: #586069; }
.token.property, .token.tag, .token.constant, .token.symbol, .token.deleted, .token.boolean, .token.number { color: #005cc5; }
.token.selector, .token.attr-name, .token.string, .token.char, .token.builtin, .token.inserted { color: #22863a; }
.token.operator, .token.entity, .token.url { color: #d73a49; }
.token.atrule, .token.attr-value, .token.keyword { color: #d73a49; }
.token.function, .token.class-name { color: #6f42c1; }
.token.regex, .token.important, .token.variable { color: #e36209; }
[data-theme="dark"] .token.comment, [data-theme="dark"] .token.prolog { color: #8b949e; }
[data-theme="dark"] .token.punctuation { color: #c9d1d9; }
[data-theme="dark"] .token.property, [data-theme="dark"] .token.tag, [data-theme="dark"] .token.constant, [data-theme="dark"] .token.boolean, [data-theme="dark"] .token.number { color: #79c0ff; }
[data-theme="dark"] .token.selector, [data-theme="dark"] .token.attr-name, [data-theme="dark"] .token.string, [data-theme="dark"] .token.char, [data-theme="dark"] .token.builtin { color: #a5d6ff; }
[data-theme="dark"] .token.operator, [data-theme="dark"] .token.atrule, [data-theme="dark"] .token.attr-value, [data-theme="dark"] .token.keyword { color: #ff7b72; }
[data-theme="dark"] .token.function, [data-theme="dark"] .token.class-name { color: #d2a8ff; }
[data-theme="dark"] .token.regex, [data-theme="dark"] .token.important, [data-theme="dark"] .token.variable { color: #ffa657; }
.math-block { overflow-x: auto; margin: 0 0 12px; }
.answer .katex-display { overflow-x: auto; overflow-y: hidden; padding: 2px 0; margin: 0 0 12px; }.math-raw { font-family: ui-monospace, Menlo, Consolas, monospace; font-size: .92em; }

.think { margin: 0 0 14px; }
.think-head {
  display: inline-flex; align-items: center; gap: 8px; padding: 6px 12px; border-radius: 10px; border: 0;
  background: var(--side); cursor: pointer; color: var(--muted); font-size: 13.5px;
}
.think-head:hover { background: var(--hover); }
.think-head svg { width: 15px; height: 15px; transition: transform .2s; }
.think.open .think-head .chev { transform: rotate(180deg); }
.think-body {
  display: none; margin-top: 10px; padding-block: 2px; padding-inline: 14px 0; border-inline-start: 2px solid var(--border);
  color: var(--muted); font-size: 14.5px; overflow-wrap: anywhere;
}
.think-body p { margin: 0 0 10px; }
.think-body > :last-child { margin-bottom: 0; }
.think.open .think-body { display: block; }
.think.empty .think-body, .think.empty .chev { display: none; }

.actions { display: flex; gap: 2px; margin-top: 6px; }
.msg.user .actions { opacity: 0; transition: opacity .15s; }
.msg.user:hover .actions { opacity: 1; }
.actions .ibtn { width: 30px; height: 30px; border-radius: 8px; }
.actions .ibtn svg { width: 16px; height: 16px; }
.stopped { display: inline-block; margin-top: 6px; font-size: 13px; color: var(--muted); }
.note { display: flex; align-items: center; flex-wrap: wrap; gap: 10px; padding: 12px 14px; border-radius: 12px; border: 1px solid var(--border); background: var(--side); font-size: 14.5px; }
.note.warn { border-color: #f5c56b; background: color-mix(in srgb, #f5c56b 12%, var(--bg)); }
.note button { border: 1px solid var(--border); background: var(--bg); border-radius: 8px; padding: 4px 12px; cursor: pointer; font-size: 14px; }
.note button:hover { border-color: var(--blue); }

.dots { display: inline-flex; gap: 5px; padding: 8px 0; }
.dots i { width: 7px; height: 7px; border-radius: 50%; background: var(--muted); opacity: .5; animation: blink 1.2s infinite ease-in-out; }
.dots i:nth-child(2) { animation-delay: .2s; }
.dots i:nth-child(3) { animation-delay: .4s; }
@keyframes blink { 0%, 80%, 100% { opacity: .25; transform: scale(.85); } 40% { opacity: .9; transform: scale(1); } }

/* composer */
.composer-wrap { padding: 0 20px 10px; flex-shrink: 0; }
.composer {
  max-width: 800px; margin: 0 auto; border: 1px solid var(--border); border-radius: 24px; background: var(--bg);
  padding: 12px 12px 10px; padding-inline-start: 18px; box-shadow: 0 4px 24px rgba(30, 40, 90, .06);
}
.composer:focus-within { border-color: color-mix(in srgb, var(--blue) 60%, var(--border)); }
.composer textarea {
  width: 100%; border: 0; outline: 0; resize: none; background: transparent; color: var(--text);
  font: inherit; font-size: 16px; line-height: 1.5; max-height: 220px; min-height: 26px; display: block; padding: 0;
}
.composer-bar { display: flex; align-items: center; gap: 8px; margin-top: 10px; }
.toggle {
  display: inline-flex; align-items: center; gap: 6px; height: 32px; padding: 0 12px; border-radius: 999px;
  border: 1px solid var(--border); background: var(--bg); cursor: pointer; font-size: 13.5px; color: var(--text);
}
.toggle svg { width: 16px; height: 16px; }
.toggle[aria-pressed="true"] { background: var(--blue-soft); border-color: color-mix(in srgb, var(--blue) 45%, transparent); color: var(--blue); }
.spacer { flex: 1; }
.send {
  width: 36px; height: 36px; border-radius: 50%; border: 0; background: var(--blue); color: #fff; cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center;
}
.send:disabled { background: #c3cbe8; cursor: default; }
[data-theme="dark"] .send:disabled { background: #3a3f57; }
.send svg { width: 18px; height: 18px; }
.send .ic-stop { display: none; }
.send.busy .ic-send { display: none; }
.send.busy .ic-stop { display: block; }
.fineprint { text-align: center; font-size: 12px; color: var(--muted); margin: 8px 0 0; }

.toast {
  position: fixed; left: 50%; bottom: 96px; transform: translateX(-50%) translateY(10px); opacity: 0; pointer-events: none;
  background: var(--text); color: var(--bg); padding: 8px 16px; border-radius: 10px; font-size: 14px; transition: opacity .2s, transform .2s; z-index: 100;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

@media (max-width: 860px) {
  .sidebar { position: fixed; top: 0; bottom: 0; inset-inline-start: 0; transform: translateX(-100%); box-shadow: 0 0 40px rgba(0, 0, 0, .2); }
  .app.sb-open .sidebar { transform: none; }
  .app.sb-closed .sidebar { margin-inline-start: 0; }
  [dir="rtl"] .sidebar { transform: translateX(100%); }
  .app.sb-open .scrim { display: block; position: fixed; inset: 0; background: rgba(0, 0, 0, .35); z-index: 25; }
  .app .topbar .open-sb { visibility: visible !important; }
}
@media (max-width: 600px) {
  .thread, .welcome { padding-left: 14px; padding-right: 14px; }
  .composer-wrap { padding: 0 10px 8px; }
  .suggest { grid-template-columns: 1fr; }
  .suggest button:nth-child(n+3) { display: none; }
  .msg.ai { gap: 0; }
  .msg.ai .avatar { display: none; }
  .msg.user .bubble { max-width: 92%; }
  .welcome { padding-top: 8vh; }
}