:root {
  color-scheme: dark;
  --bg: #0d0f14;
  --panel: #11141c;
  --panel-2: #171b25;
  --text: #eef2ff;
  --muted: #9aa4b2;
  --border: rgba(255,255,255,.09);
  --accent: #6d5dfc;
  --accent-2: #8a7cff;
  --danger: #ff6b6b;
  --ok: #18c58f;
  --shadow: 0 18px 60px rgba(0,0,0,.35);
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background: radial-gradient(circle at top left, rgba(109,93,252,.18), transparent 35%), var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button, input, textarea, select { font: inherit; }
button { cursor: pointer; }

.app-shell {
  display: grid;
  grid-template-columns: 310px 1fr;
  height: 100vh;
  min-height: 100vh;
}

.sidebar {
  background: rgba(17,20,28,.94);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.sidebar-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 18px;
  border-bottom: 1px solid var(--border);
}

.sidebar-header span {
  display: block;
  color: var(--muted);
  font-size: 12px;
  margin-top: 2px;
}

.app-logo, .brand-dot {
  width: 42px;
  height: 42px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: white;
  font-weight: 800;
  box-shadow: var(--shadow);
}

.new-chat {
  margin: 16px;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 13px 14px;
  background: var(--accent);
  color: white;
  font-weight: 750;
}
.new-chat:hover { background: var(--accent-2); }

.search-wrap { padding: 0 16px 12px; }
.search-wrap input {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(255,255,255,.05);
  color: var(--text);
  outline: none;
  padding: 12px 13px;
}
.search-wrap input:focus { border-color: rgba(138,124,255,.7); }

.chat-list {
  overflow-y: auto;
  padding: 0 10px 12px;
  flex: 1;
}

.chat-item {
  width: 100%;
  border: 1px solid transparent;
  border-radius: 12px;
  background: transparent;
  color: var(--text);
  text-align: left;
  padding: 11px 12px;
  margin: 3px 0;
  display: grid;
  gap: 4px;
}
.chat-item:hover { background: rgba(255,255,255,.05); }
.chat-item.active {
  background: rgba(109,93,252,.16);
  border-color: rgba(109,93,252,.36);
}
.chat-name {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  font-weight: 650;
}
.chat-date { color: var(--muted); font-size: 12px; }
.empty-list { color: var(--muted); padding: 12px; font-size: 14px; }

.sidebar-footer {
  border-top: 1px solid var(--border);
  padding: 14px 16px;
}
.sidebar-footer a { color: var(--muted); text-decoration: none; }
.sidebar-footer a:hover { color: var(--text); }

.chat-main {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
}

.topbar {
  height: 72px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 12px 18px;
  background: rgba(13,15,20,.72);
  backdrop-filter: blur(14px);
}
.top-title { flex: 1; min-width: 0; }
.top-title strong {
  display: block;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.top-title span { color: var(--muted); font-size: 12px; }

.icon-btn {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(255,255,255,.05);
  color: var(--text);
}

#modelSelect {
  max-width: 260px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #171b25;
  color: var(--text);
  padding: 10px 12px;
  outline: none;
  color-scheme: dark;
  appearance: auto;
}

#modelSelect:focus {
  border-color: rgba(138,124,255,.7);
  box-shadow: 0 0 0 3px rgba(109,93,252,.18);
}

#modelSelect option,
#modelSelect optgroup {
  background-color: #171b25;
  color: #eef2ff;
}

#modelSelect option:checked {
  background-color: #6d5dfc;
  color: #ffffff;
}

#modelSelect option:disabled {
  color: #7d8797;
}

.messages {
  flex: 1;
  overflow-y: auto;
  padding: 26px max(18px, 8vw);
  scroll-behavior: smooth;
}

.welcome {
  min-height: 70%;
  display: grid;
  place-content: center;
  text-align: center;
  gap: 12px;
  color: var(--muted);
}
.welcome-logo {
  width: 68px;
  height: 68px;
  border-radius: 24px;
  display: grid;
  place-items: center;
  margin: 0 auto 8px;
  color: white;
  font-size: 28px;
  background: linear-gradient(135deg, var(--accent), #00d4ff);
  box-shadow: var(--shadow);
}
.welcome h1 { margin: 0; color: var(--text); font-size: clamp(26px, 4vw, 42px); }
.welcome p { margin: 0; }
.setup-warning {
  margin-top: 12px;
  border: 1px solid rgba(255,193,7,.25);
  color: #ffd36e;
  background: rgba(255,193,7,.08);
  border-radius: 14px;
  padding: 12px 14px;
}

.msg-row {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 12px;
  margin: 18px 0;
  align-items: flex-start;
}
.avatar {
  width: 42px;
  height: 42px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: rgba(255,255,255,.08);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 12px;
  font-weight: 800;
}
.msg-row.user .avatar { background: rgba(109,93,252,.22); }
.msg-row.assistant .avatar { background: rgba(24,197,143,.15); color: #aaf7df; }

.bubble {
  max-width: 920px;
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 15px 16px;
  background: rgba(255,255,255,.045);
  line-height: 1.58;
  overflow-wrap: anywhere;
}
.msg-row.user .bubble { background: rgba(109,93,252,.12); }
.content code {
  background: rgba(255,255,255,.1);
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: 1px 5px;
}
pre {
  position: relative;
  white-space: pre-wrap;
  background: #090b10;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
  overflow-x: auto;
}
pre code {
  background: transparent !important;
  border: 0 !important;
  padding: 0 !important;
}
.copy-code {
  position: absolute;
  right: 10px;
  top: 10px;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: rgba(255,255,255,.08);
  color: var(--text);
  padding: 6px 9px;
  font-size: 12px;
}
.thinking { color: var(--muted); }
.error-text { color: var(--danger); }

.composer-wrap {
  padding: 14px max(18px, 8vw) 16px;
  border-top: 1px solid var(--border);
  background: rgba(13,15,20,.86);
}
.composer {
  display: grid;
  grid-template-columns: 1fr 48px;
  gap: 10px;
  align-items: end;
  max-width: 980px;
  margin: 0 auto;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: rgba(255,255,255,.06);
  padding: 10px;
}
.composer textarea {
  width: 100%;
  resize: none;
  border: 0;
  outline: none;
  background: transparent;
  color: var(--text);
  padding: 12px 10px;
  max-height: 180px;
}
.composer button {
  width: 48px;
  height: 48px;
  border: 0;
  border-radius: 16px;
  background: var(--accent);
  color: white;
  font-weight: 800;
}
.composer button:disabled { opacity: .55; cursor: not-allowed; }
.composer-wrap small {
  display: block;
  max-width: 980px;
  margin: 8px auto 0;
  color: var(--muted);
  text-align: center;
}

.overlay { display: none; }

.login-body {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 20px;
}
.login-card {
  width: min(430px, 100%);
  background: rgba(17,20,28,.88);
  border: 1px solid var(--border);
  border-radius: 26px;
  box-shadow: var(--shadow);
  padding: 28px;
}
.login-card h1 { margin: 16px 0 6px; }
.login-card p { color: var(--muted); margin: 0 0 22px; }
.login-card label { display: block; margin-bottom: 8px; color: var(--muted); }
.login-card input {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: rgba(255,255,255,.06);
  color: var(--text);
  padding: 14px;
  outline: none;
}
.login-card button {
  width: 100%;
  margin-top: 14px;
  border: 0;
  border-radius: 14px;
  padding: 14px;
  background: var(--accent);
  color: white;
  font-weight: 800;
}
.login-card small { display: block; color: var(--muted); margin-top: 18px; line-height: 1.45; }
.alert {
  border: 1px solid rgba(255,107,107,.3);
  background: rgba(255,107,107,.1);
  color: #ffb4b4;
  border-radius: 12px;
  padding: 10px 12px;
  margin-bottom: 14px;
}

@media (max-width: 850px) {
  .app-shell { grid-template-columns: 1fr; }
  .sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    width: min(86vw, 320px);
    z-index: 40;
    transform: translateX(-105%);
    transition: transform .22s ease;
    box-shadow: var(--shadow);
  }
  .sidebar.open { transform: translateX(0); }
  .icon-btn { display: grid; place-items: center; }
  .overlay.show {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,.5);
    z-index: 30;
  }
  #modelSelect { max-width: 150px; font-size: 13px; }
  .topbar { padding: 10px 12px; height: 64px; }
  .messages { padding: 18px 14px; }
  .msg-row { grid-template-columns: 34px 1fr; gap: 9px; }
  .avatar { width: 34px; height: 34px; border-radius: 11px; font-size: 10px; }
  .bubble { padding: 13px; border-radius: 16px; }
  .composer-wrap { padding: 10px 10px 12px; }
  .composer { border-radius: 18px; grid-template-columns: 1fr 44px; }
  .composer button { width: 44px; height: 44px; border-radius: 14px; }
}