:root {
  --paper: #fbfcfd;
  --surface: #ffffff;
  --surface-2: #f2f6f8;
  --ink: #1b242b;
  --ink-2: #5a6b77;
  --ink-3: #8b9aa5;
  --line: #e2e9ee;
  --accent: #1f5673;
  --accent-soft: #e8f0f4;
  --ok: #2f7d5d;
  --warn: #a8620f;
  --err: #a63a30;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(27, 36, 43, .05), 0 8px 24px rgba(27, 36, 43, .06);
  --max: 820px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #12181c;
    --surface: #182026;
    --surface-2: #1e282f;
    --ink: #e8eef2;
    --ink-2: #a3b2bc;
    --ink-3: #74838d;
    --line: #2a353d;
    --accent: #7fb8d4;
    --accent-soft: #1c2a33;
    --ok: #6cc39a;
    --warn: #d9a05b;
    --err: #e08279;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px rgba(0, 0, 0, .25);
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
}

body {
  background: var(--paper);
  color: var(--ink);
  font: 15px/1.7 "Noto Sans TC", "微軟正黑體", "Microsoft JhengHei", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

/* ── 頂列 ─────────────────────────────────────────── */

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 20px;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  flex-wrap: wrap;
  position: sticky;
  top: 0;
  z-index: 20;
}

.brand { display: flex; align-items: center; gap: 11px; }

.mark {
  width: 32px; height: 32px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 50% 42%, var(--paper) 0 4.5px, transparent 5px),
    conic-gradient(from 210deg, var(--accent), #4d8fae, var(--accent));
  flex: none;
}

.brand-text { display: flex; flex-direction: column; line-height: 1.25; }
.brand-text strong { font-size: 15px; letter-spacing: .01em; }
.brand-text span { font-size: 12px; color: var(--ink-3); }

.controls { display: flex; align-items: flex-end; gap: 10px; flex-wrap: wrap; }

.field { display: flex; flex-direction: column; gap: 3px; }
.field > span { font-size: 11px; color: var(--ink-3); padding-left: 2px; }

select, .ghost {
  font: inherit;
  font-size: 13px;
  color: var(--ink);
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 9px;
  padding: 6px 10px;
  cursor: pointer;
  max-width: 230px;
}

select:focus-visible, .ghost:focus-visible, textarea:focus-visible, button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.ghost:hover { background: var(--accent-soft); border-color: var(--accent); }

/* ── 提示橫幅 ─────────────────────────────────────── */

.banner {
  margin: 0;
  padding: 11px 20px;
  font-size: 13.5px;
  background: color-mix(in srgb, var(--warn) 12%, var(--surface));
  color: var(--ink);
  border-bottom: 1px solid var(--line);
}
.banner code {
  background: var(--surface-2);
  padding: 1px 5px;
  border-radius: 5px;
  font-size: .92em;
}
.banner a { color: var(--accent); }

/* ── 對話區 ───────────────────────────────────────── */

.chat {
  flex: 1;
  overflow-y: auto;
  padding: 28px 20px 12px;
  scroll-behavior: smooth;
}

.welcome { max-width: var(--max); margin: 6vh auto 0; }
.welcome h1 { font-size: 26px; margin: 0 0 8px; letter-spacing: -.01em; }
.lede { color: var(--ink-2); margin: 0 0 22px; max-width: 56ch; }

.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chips button {
  font: inherit;
  font-size: 13.5px;
  padding: 8px 14px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink-2);
  cursor: pointer;
  transition: .14s;
}
.chips button:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
  transform: translateY(-1px);
}

.turn { max-width: var(--max); margin: 0 auto 22px; }

.bubble-user {
  margin-left: auto;
  max-width: 88%;
  width: fit-content;
  background: var(--accent);
  color: #fff;
  padding: 10px 15px;
  border-radius: 15px 15px 4px 15px;
  white-space: pre-wrap;
  word-break: break-word;
  box-shadow: var(--shadow);
}
@media (prefers-color-scheme: dark) { .bubble-user { color: #0f171c; font-weight: 500; } }

.bubble-ai {
  white-space: pre-wrap;
  word-break: break-word;
  padding: 2px 0;
}
.bubble-ai strong { font-weight: 650; }

/* ── 工具執行卡片 ─────────────────────────────────── */

.tool {
  display: flex;
  align-items: flex-start;
  gap: 9px;
  font-size: 13.5px;
  color: var(--ink-2);
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 8px 12px;
  margin: 8px 0;
}
.tool .dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--ink-3);
  margin-top: 8px;
  flex: none;
}
.tool.running .dot { background: var(--accent); animation: pulse 1.1s ease-in-out infinite; }
.tool.ok .dot { background: var(--ok); }
.tool.fail .dot { background: var(--err); }
.tool .body { min-width: 0; flex: 1; }
.tool .body b { font-weight: 600; color: var(--ink); }
.tool .body .detail {
  display: block;
  font-size: 12.5px;
  color: var(--ink-3);
  white-space: pre-wrap;
  margin-top: 2px;
  word-break: break-word;
}

@keyframes pulse { 0%,100% { opacity: 1; } 50% { opacity: .25; } }

/* ── 產出檔案卡片 ─────────────────────────────────── */

.artifact {
  display: flex;
  align-items: center;
  gap: 12px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  background: var(--surface);
  border-radius: 11px;
  padding: 12px 14px;
  margin: 10px 0;
  box-shadow: var(--shadow);
}
.artifact .icon {
  width: 34px; height: 34px;
  display: grid; place-items: center;
  border-radius: 8px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 15px;
  flex: none;
}
.artifact .meta { flex: 1; min-width: 0; }
.artifact .name {
  font-weight: 600; font-size: 14px;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.artifact .where { font-size: 12px; color: var(--ink-3); }
.artifact a {
  font-size: 13px;
  color: var(--accent);
  text-decoration: none;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 5px 11px;
  white-space: nowrap;
}
.artifact a:hover { background: var(--accent-soft); border-color: var(--accent); }

/* ── 狀態與錯誤 ───────────────────────────────────── */

.status { font-size: 13.5px; color: var(--ink-3); margin: 6px 0; }
.status::after {
  content: "";
  display: inline-block;
  width: 3px; height: 3px;
  border-radius: 50%;
  background: currentColor;
  margin-left: 6px;
  vertical-align: middle;
  animation: pulse .9s ease-in-out infinite;
}

.error {
  border: 1px solid color-mix(in srgb, var(--err) 40%, var(--line));
  background: color-mix(in srgb, var(--err) 8%, var(--surface));
  border-radius: 10px;
  padding: 11px 14px;
  font-size: 13.5px;
  margin: 8px 0;
  white-space: pre-wrap;
}

/* ── 輸入區 ───────────────────────────────────────── */

.composer {
  border-top: 1px solid var(--line);
  background: var(--surface);
  padding: 12px 20px calc(12px + env(safe-area-inset-bottom));
}

.composer-inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  align-items: flex-end;
  gap: 9px;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 7px 7px 7px 14px;
  transition: border-color .15s;
}
.composer-inner:focus-within { border-color: var(--accent); }

textarea {
  flex: 1;
  font: inherit;
  color: var(--ink);
  background: none;
  border: none;
  resize: none;
  outline: none;
  max-height: 200px;
  padding: 6px 0;
  line-height: 1.6;
}

#send {
  width: 36px; height: 36px;
  display: grid; place-items: center;
  border: none;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  flex: none;
  transition: .14s;
}
@media (prefers-color-scheme: dark) { #send { color: #0f171c; } }
#send:hover:not(:disabled) { filter: brightness(1.1); }
#send:disabled { opacity: .4; cursor: not-allowed; }

.hint {
  max-width: var(--max);
  margin: 7px auto 0;
  font-size: 11.5px;
  color: var(--ink-3);
  text-align: center;
}

@media (max-width: 640px) {
  .topbar { padding: 10px 14px; }
  .chat { padding: 18px 14px 8px; }
  .composer { padding: 10px 14px calc(10px + env(safe-area-inset-bottom)); }
  .welcome { margin-top: 2vh; }
  .welcome h1 { font-size: 22px; }
  select, .ghost { max-width: 150px; }
}