:root {
  --bg: #0f1115;
  --bg-soft: #161a21;
  --bg-elev: #1d222b;
  --line: #2a303c;
  --fg: #e6e9ef;
  --fg-dim: #8b94a7;
  --accent: #4f8cff;
  --danger: #ff5d5d;
  --radius: 12px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--fg);
  font: 15px/1.6 system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
}

#app {
  display: flex;
  height: 100dvh;
  overflow: hidden;
}

/* ---------- 侧栏 ---------- */
#sidebar {
  width: 264px;
  flex: 0 0 264px;
  display: flex;
  flex-direction: column;
  background: var(--bg-soft);
  border-right: 1px solid var(--line);
}

.side-head {
  display: flex;
  gap: 8px;
  padding: 12px;
}

#convList {
  flex: 1;
  overflow-y: auto;
  padding: 0 8px 8px;
}

.conv {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 10px;
  margin-bottom: 2px;
  border-radius: 8px;
  cursor: pointer;
  color: var(--fg-dim);
  font-size: 14px;
}

.conv:hover { background: var(--bg-elev); color: var(--fg); }
.conv.active { background: var(--bg-elev); color: var(--fg); }

.conv span {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.conv .del {
  opacity: 0;
  border: 0;
  background: none;
  color: var(--fg-dim);
  cursor: pointer;
  font-size: 14px;
  padding: 0 2px;
}

.conv:hover .del { opacity: 1; }
.conv .del:hover { color: var(--danger); }

.side-foot {
  padding: 8px 14px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  color: var(--fg-dim);
}

.status.err { color: var(--danger); }

/* ---------- 主区 ---------- */
#main {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

#topbar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--line);
}

#topbar h1 {
  flex: 1;
  margin: 0;
  font-size: 15px;
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#model {
  background: var(--bg-elev);
  color: var(--fg);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 6px 8px;
  font-size: 13px;
  max-width: 220px;
}

#messages {
  flex: 1;
  overflow-y: auto;
  padding: 20px 16px 8px;
  scroll-behavior: smooth;
}

.msg {
  max-width: 780px;
  margin: 0 auto 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.msg .who {
  font-size: 12px;
  color: var(--fg-dim);
}

.msg .body {
  padding: 12px 14px;
  border-radius: var(--radius);
  background: var(--bg-soft);
  border: 1px solid var(--line);
  white-space: pre-wrap;
  word-break: break-word;
}

.msg.user .body {
  background: #1b2739;
  border-color: #24344d;
}

.msg .body pre {
  background: #0b0e13;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 12px;
  overflow-x: auto;
  margin: 8px 0;
  white-space: pre;
}

.msg .body code {
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: 13px;
}

.msg .body :not(pre) > code {
  background: #0b0e13;
  padding: 1px 5px;
  border-radius: 4px;
}

.cursor::after {
  content: "▍";
  color: var(--accent);
  animation: blink 1s steps(1) infinite;
}

@keyframes blink { 50% { opacity: 0; } }

.empty {
  max-width: 780px;
  margin: 12vh auto 0;
  text-align: center;
  color: var(--fg-dim);
}

.empty h2 { color: var(--fg); font-size: 20px; margin-bottom: 8px; }

/* ---------- 输入 ---------- */
#composer {
  display: flex;
  gap: 10px;
  align-items: flex-end;
  padding: 12px 16px 16px;
  border-top: 1px solid var(--line);
  max-width: 812px;
  margin: 0 auto;
  width: 100%;
}

#input {
  flex: 1;
  resize: none;
  max-height: 40vh;
  padding: 11px 13px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--bg-soft);
  color: var(--fg);
  font: inherit;
}

#input:focus { outline: none; border-color: var(--accent); }

button {
  font: inherit;
  cursor: pointer;
  border-radius: 9px;
  border: 1px solid var(--line);
  padding: 9px 14px;
  background: var(--bg-elev);
  color: var(--fg);
}

button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  font-weight: 600;
}

button.primary:disabled { opacity: .5; cursor: default; }
button.ghost { background: transparent; }

/* ---------- 设置弹窗 ---------- */
dialog {
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--bg-soft);
  color: var(--fg);
  padding: 0;
  width: min(92vw, 460px);
}

dialog::backdrop { background: rgba(0,0,0,.6); }

.dlg { padding: 20px; display: flex; flex-direction: column; gap: 14px; }
.dlg h2 { margin: 0; font-size: 17px; }

.dlg label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 13px;
  color: var(--fg-dim);
}

.dlg input {
  padding: 10px 12px;
  border-radius: 9px;
  border: 1px solid var(--line);
  background: var(--bg);
  color: var(--fg);
  font: inherit;
}

.dlg input:focus { outline: none; border-color: var(--accent); }
.hint { margin: 0; font-size: 12px; color: var(--fg-dim); }
.dlg menu { display: flex; justify-content: flex-end; gap: 8px; margin: 4px 0 0; padding: 0; }

.only-mobile { display: none; }

@media (max-width: 760px) {
  .only-mobile { display: inline-block; }
  #sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    z-index: 20;
    transform: translateX(-100%);
    transition: transform .2s;
    box-shadow: 8px 0 24px rgba(0,0,0,.4);
  }
  #sidebar.open { transform: none; }
  #messages { padding: 14px 12px 4px; }
  #composer { padding: 10px 12px 14px; }
}