:root {
  /* Light theme (default) */
  --bg: #f7f7f5;
  --panel: #ffffff;
  --text: #111111;
  --muted: #555555;
  --border: rgba(0, 0, 0, 0.10);
  --danger: #b00020;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #101010;
    --panel: #151515;
    --text: #f2f2f2;
    --muted: #b7b7b7;
    --border: rgba(255, 255, 255, 0.10);
    --danger: #ff5a6a;
    --shadow: 0 18px 60px rgba(0, 0, 0, 0.50);
  }
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
  margin: 0;
  color: var(--text);
  background: var(--bg);
  font: 14px/1.35 system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
}

body {
  /* Prevent "whole page scrolls a few px" — only the chats list + messages should scroll */
  overflow: hidden;
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
}

code { font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace; }

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
  flex: 0 0 auto;
}

.icon-btn {
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text);
  border-radius: 10px;
  padding: 8px 10px;
  cursor: pointer;
  line-height: 1;
}
.icon-btn:hover { box-shadow: var(--shadow); }

.brand {
  display: flex;
  gap: 10px;
  align-items: center;
}
.brand-title { font-weight: 760; letter-spacing: 0.2px; }

.topbar-actions { display: flex; gap: 10px; }

.layout {
  display: grid;
  grid-template-columns: var(--sidebar-width, 340px) var(--sidebar-resizer-width, 6px) 1fr;
  flex: 1 1 auto;
  min-height: 0; /* critical for nested scroll containers */
}

.sidebar {
  border-right: 1px solid var(--border);
  background: var(--panel);
  padding: 8px;
  overflow: hidden;
  min-height: 0;
  display: flex;
  flex-direction: column;
}
.sidebar.collapsed {
  padding: 8px 8px;
  align-items: center;
}
.sidebar-resizer {
  cursor: col-resize;
  background: var(--panel);
  border-left: none;
  border-right: 1px solid var(--border);
}
.sidebar-resizer:hover {
  background: rgba(0, 0, 0, 0.06);
}
.sidebar-resizer.hidden { display: none; }
.sidebar-header {
  display: flex;
  gap: 6px;
  margin-bottom: 6px;
  align-items: center;
}
.spacer { flex: 1 1 auto; }
.chats {
  overflow: auto;
  flex: 1 1 auto;
  min-height: 0;
  padding-right: 4px;
}
.sidebar.collapsed .chats { display: none; }
.sidebar.collapsed #btn-new-chat { display: none; }
.sidebar.collapsed .spacer { display: none; }
.sidebar.collapsed .sidebar-header { justify-content: center; }

.sidebar .icon-btn {
  padding: 6px 8px;
  border-radius: 10px;
}

.chat {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-height: 0;
}

.chat-settings-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
  flex: 0 0 auto;
}
.chat-settings-title {
  font-weight: 760;
  letter-spacing: 0.2px;
}
.chat-settings-right { display: flex; gap: 10px; align-items: center; }

.status {
  margin: 12px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--muted);
  background: var(--panel);
}
.hidden { display: none; }

.messages {
  overflow: auto;
  padding: 16px;
  min-height: 0;
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
}

.composer {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 10px;
  padding: 16px;
  border-top: 1px solid var(--border);
  background: var(--panel);
  flex: 0 0 auto;
}

.prompt {
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text);
  padding: 12px 12px;
  border-radius: 12px;
  outline: none;
  width: 100%;
  resize: none;
  overflow-y: hidden;
  min-height: 44px;
  max-height: 240px; /* ~10-ish lines depending on font metrics */
  line-height: 1.35;
  font: inherit;
}
.prompt:focus { border-color: rgba(0, 0, 0, 0.22); }

.btn {
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text);
  font-weight: 720;
  padding: 10px 12px;
  border-radius: 12px;
  cursor: pointer;
}
.btn.secondary {
  background: var(--panel);
  color: var(--text);
}
.btn.danger {
  background: var(--panel);
  color: var(--danger);
  border-color: var(--danger);
}
.btn:hover { box-shadow: var(--shadow); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: 0.55; cursor: not-allowed; }

.toasts {
  position: fixed;
  top: 12px;
  right: 12px;
  z-index: 1000;
  display: grid;
  gap: 10px;
  pointer-events: none;
}
.toast {
  pointer-events: auto;
  width: min(420px, calc(100vw - 24px));
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--panel);
  box-shadow: var(--shadow);
  padding: 10px 12px;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  align-items: start;
  transform: translateX(16px);
  opacity: 0;
  animation: toast-in 180ms ease-out forwards;
}
.toast[data-kind="error"] {
  border-color: rgba(176, 0, 32, 0.35);
}
.toast-msg { color: var(--text); white-space: pre-wrap; }
.toast-close {
  border: 1px solid var(--border);
  background: transparent;
  color: var(--muted);
  border-radius: 10px;
  padding: 6px 8px;
  cursor: pointer;
  line-height: 1;
}
.toast-close:hover { box-shadow: var(--shadow); }
@keyframes toast-in {
  from { transform: translateX(16px); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

.chat-item {
  display: grid;
  gap: 6px;
  padding: 6px 8px;
  border-radius: 12px;
  border: 1px solid transparent;
  cursor: pointer;
}
.chat-item:hover { background: rgba(0, 0, 0, 0.04); }
.chat-item.active { background: rgba(0, 0, 0, 0.06); border-color: rgba(0, 0, 0, 0.12); }
.chat-title { font-weight: 700; }
.chat-meta { color: var(--muted); font-size: 12px; display: flex; gap: 8px; }

.msg-row {
  display: flex;
  margin-bottom: 12px;
}
.msg-row.user { justify-content: flex-end; }
.msg-row.assistant { justify-content: flex-start; }

.msg {
  max-width: min(860px, 82%);
  margin: 0;
  padding: 12px 12px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--panel);
}
.msg.user { background: rgba(0, 0, 0, 0.03); }
.msg.assistant { background: var(--panel); }
.msg-role { color: var(--muted); font-size: 12px; margin-bottom: 6px; }

.msg-content {
  /* Markdown output */
  line-height: 1.45;
}
.msg-content > :first-child { margin-top: 0; }
.msg-content > :last-child { margin-bottom: 0; }
.msg-content p { margin: 8px 0; }
.msg-content ul, .msg-content ol { margin: 8px 0 8px 22px; padding: 0; }
.msg-content li { margin: 4px 0; }
.msg-content a { color: inherit; text-decoration: underline; text-underline-offset: 2px; }
.msg-content blockquote {
  margin: 10px 0;
  padding: 8px 10px;
  border-left: 3px solid var(--border);
  color: var(--muted);
}
.msg-content pre {
  margin: 10px 0;
  padding: 10px 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: rgba(0, 0, 0, 0.04);
  overflow: auto;
}
.msg-content code {
  background: rgba(0, 0, 0, 0.05);
  border: 1px solid var(--border);
  padding: 1px 6px;
  border-radius: 10px;
}
.msg-content pre code {
  background: transparent;
  border: none;
  padding: 0;
}

.model-list {
  display: grid;
  gap: 8px;
  max-height: min(56vh, 520px);
  min-height: 220px;
  overflow: auto;
  padding-right: 4px;
}
.model-sections { display: grid; gap: 14px; }
.model-section-title { font-weight: 720; margin: 6px 0 6px 0; }
.model-item {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  padding: 10px 10px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--panel);
  cursor: pointer;
  text-align: left;
}
.model-item:hover { box-shadow: var(--shadow); }
.model-item-title { font-weight: 720; }
.model-item-sub { color: var(--muted); font-size: 12px; }
.model-item-main { display: grid; gap: 4px; }
.model-item-actions { display: flex; align-items: start; gap: 8px; }
.bookmark-btn {
  border: 1px solid var(--border);
  background: transparent;
  color: var(--muted);
  border-radius: 10px;
  padding: 6px 8px;
  cursor: pointer;
  line-height: 1;
}
.bookmark-btn[data-active="1"] { color: var(--text); }
.bookmark-btn:hover { box-shadow: var(--shadow); }

.dialog::backdrop {
  background: rgba(0, 0, 0, 0.6);
}
.dialog {
  border: 1px solid var(--border);
  border-radius: 18px;
  width: min(640px, calc(100vw - 28px));
  background: var(--panel);
  color: var(--text);
  box-shadow: var(--shadow);
}
.dialog-inner { padding: 16px; }
.dialog-title { font-size: 16px; font-weight: 760; margin-bottom: 12px; }
.label { display: grid; gap: 6px; margin: 12px 0; }
.label-title { font-weight: 680; }
.input {
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text);
  padding: 10px 10px;
  border-radius: 12px;
  outline: none;
}
.hint { color: var(--muted); font-size: 12px; }
.dialog-actions { display: flex; justify-content: flex-end; gap: 10px; margin-top: 14px; }

@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar-resizer { display: none; }
  .sidebar { height: 240px; border-right: none; border-bottom: 1px solid var(--border); }
}