:root {
  --bg: #0f1419;
  --bg-accent: #141c24;
  --surface: #1a222c;
  --surface-2: #243040;
  --line: rgba(232, 238, 244, 0.08);
  --text: #e8eef4;
  --muted: #8b9cb0;
  --accent: #3d9cf0;
  --accent-2: #5eead4;
  --voice: #34d399;
  --danger: #f07178;
  --shadow: 0 16px 50px rgba(0, 0, 0, 0.28);
  --radius: 18px;
  --font: "PingFang TC", "Microsoft JhengHei", "Noto Sans TC", "Source Han Sans TC", "Segoe UI", sans-serif;
  color-scheme: dark;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: var(--font);
  background:
    radial-gradient(1200px 500px at 10% -10%, rgba(61, 156, 240, 0.16), transparent 55%),
    radial-gradient(900px 420px at 100% 0%, rgba(94, 234, 212, 0.08), transparent 50%),
    var(--bg);
  color: var(--text);
  min-height: 100dvh;
}

button, input, textarea { font: inherit; color: inherit; }
button { cursor: pointer; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.btn {
  border: 0;
  border-radius: 12px;
  padding: 0.7rem 1rem;
  background: var(--surface-2);
  transition: transform 0.12s ease, background 0.12s ease, opacity 0.12s ease;
}
.btn:hover { background: #2c3a4d; }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: 0.6; cursor: not-allowed; }
.btn.primary { background: var(--accent); color: #061018; font-weight: 700; }
.btn.primary:hover { background: #62b0f5; }
.btn.ghost { background: transparent; border: 1px solid var(--line); }
.btn.voice-join { background: var(--voice); color: #062016; font-weight: 700; }
.btn.voice-join.is-on { background: #255348; color: #d1fae5; }
.btn.muted { background: #3a2a2c; color: #ffd4d6; }

.form-error { color: var(--danger); margin: 0.2rem 0 0; font-size: 0.92rem; }

.auth-wrap {
  min-height: 100dvh;
  display: grid;
  place-items: center;
  padding: 1.25rem;
}
.auth-card {
  width: min(420px, 100%);
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  border: 1px solid var(--line);
  border-radius: 24px;
  padding: 1.6rem 1.4rem 1.4rem;
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
}
.brand { text-align: center; margin-bottom: 1.2rem; }
.brand-mark {
  display: inline-block;
  width: 46px;
  height: 46px;
  border-radius: 14px;
  background:
    linear-gradient(160deg, #3d9cf0, #5eead4);
  margin-bottom: 0.7rem;
}
.brand h1 { margin: 0 0 0.35rem; font-size: 1.6rem; letter-spacing: 0.04em; }
.brand p { margin: 0; color: var(--muted); }

.tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.4rem;
  background: var(--bg);
  padding: 0.3rem;
  border-radius: 14px;
  margin-bottom: 1rem;
}
.tab {
  border: 0;
  background: transparent;
  color: var(--muted);
  border-radius: 11px;
  padding: 0.65rem;
  font-weight: 600;
}
.tab.is-active { background: var(--surface-2); color: var(--text); }

#auth-form { display: grid; gap: 0.8rem; }
#auth-form label { display: grid; gap: 0.35rem; font-size: 0.92rem; color: var(--muted); }
#auth-form input, #composer-input {
  width: 100%;
  border: 1px solid var(--line);
  background: var(--bg);
  border-radius: 12px;
  padding: 0.75rem 0.85rem;
  outline: none;
}
#auth-form input:focus, #composer-input:focus {
  border-color: color-mix(in srgb, var(--accent) 70%, white);
  box-shadow: 0 0 0 3px rgba(61, 156, 240, 0.2);
}

.app {
  height: 100dvh;
  display: grid;
  grid-template-rows: auto auto 1fr;
}
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.8rem 1rem;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--surface) 80%, transparent);
  backdrop-filter: blur(14px);
}
.topbar-title { display: flex; flex-direction: column; gap: 0.1rem; }
.topbar-title strong { font-size: 1.05rem; }
.online-count, .topbar-user { color: var(--muted); font-size: 0.88rem; }
.topbar-user { display: flex; align-items: center; gap: 0.6rem; }
#me-name { color: var(--text); font-weight: 600; }

.voice-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem 1rem;
  align-items: center;
  justify-content: space-between;
  padding: 0.7rem 1rem;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(52, 211, 153, 0.08), transparent 50%);
}
.voice-controls { display: flex; flex-wrap: wrap; align-items: center; gap: 0.55rem; }
.voice-status { margin: 0; color: var(--muted); font-size: 0.9rem; }
.voice-people {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin: 0;
  padding: 0;
}
.voice-people li {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.25rem 0.65rem 0.25rem 0.3rem;
  font-size: 0.86rem;
}
.avatar {
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-size: 0.7rem;
  font-weight: 700;
  background: #2a3b50;
}
.voice-people li.is-speaking {
  border-color: var(--accent-2);
  box-shadow: 0 0 0 3px rgba(94, 234, 212, 0.25);
}
.voice-people li.is-muted .avatar { background: #3a2a2c; color: #ffd4d6; }
.mic-icon { font-size: 0.78rem; color: var(--muted); }
.voice-people li.is-speaking .mic-icon { color: var(--accent-2); }

.chat-layout {
  min-height: 0;
  display: grid;
  grid-template-columns: 220px 1fr;
}
.sidebar {
  border-right: 1px solid var(--line);
  padding: 1rem 0.85rem;
  overflow: auto;
  background: color-mix(in srgb, var(--bg-accent) 80%, transparent);
}
.sidebar h2 { margin: 0 0 0.7rem; font-size: 0.82rem; color: var(--muted); font-weight: 600; letter-spacing: 0.06em; }
.sidebar ul, .voice-people { list-style: none; }
.sidebar ul { margin: 0; padding: 0; display: grid; gap: 0.35rem; }
.sidebar li {
  padding: 0.45rem 0.55rem;
  border-radius: 10px;
  background: var(--surface);
}

.chat-main { min-width: 0; display: grid; grid-template-rows: 1fr auto auto; }
.messages {
  overflow: auto;
  padding: 1rem 1rem 0.4rem;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}
.msg {
  max-width: min(72ch, 100%);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px 16px 16px 6px;
  padding: 0.55rem 0.75rem;
}
.msg.is-me {
  align-self: flex-end;
  background: #17324a;
  border-radius: 16px 16px 6px 16px;
}
.msg-meta { display: flex; gap: 0.6rem; align-items: baseline; margin-bottom: 0.15rem; }
.msg-user { font-weight: 700; font-size: 0.9rem; }
.msg-time { color: var(--muted); font-size: 0.75rem; }
.msg-body { white-space: pre-wrap; word-break: break-word; line-height: 1.5; }

.composer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.55rem;
  padding: 0.7rem 1rem calc(0.85rem + env(safe-area-inset-bottom));
  border-top: 1px solid var(--line);
  background: color-mix(in srgb, var(--surface) 88%, transparent);
}
#composer-input {
  resize: none;
  max-height: 8rem;
  min-height: 2.7rem;
  line-height: 1.45;
}
.composer-error { padding: 0 1rem 0.6rem; }

.empty-hint { color: var(--muted); text-align: center; margin: 2rem 0; }

@media (max-width: 720px) {
  .chat-layout { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .msg { max-width: 92%; }
  .topbar, .voice-bar { padding-left: 0.8rem; padding-right: 0.8rem; }
  .voice-bar { align-items: flex-start; }
}

.form-hint { color: var(--muted); margin: 0.15rem 0 0; font-size: 0.9rem; }
.badge-admin {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 0.05rem 0.45rem;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: #062016;
  background: var(--accent-2);
  vertical-align: middle;
}
.msg-user, .voice-people li, .sidebar li, .topbar-user {
  flex-wrap: wrap;
}
.msg-meta { flex-wrap: wrap; align-items: center; }
.msg-del {
  margin-left: auto;
  border: 0;
  background: transparent;
  color: var(--muted);
  padding: 0;
  font-size: 0.78rem;
}
.msg-del:hover { color: var(--danger); }
.name-row { display: inline-flex; align-items: center; gap: 0.35rem; }

.admin-panel {
  position: fixed;
  inset: 0;
  background: rgba(4, 8, 12, 0.55);
  display: grid;
  place-items: end center;
  z-index: 30;
  padding: 1rem;
}
.admin-panel[hidden] { display: none; }
.admin-sheet {
  width: min(560px, 100%);
  max-height: min(86dvh, 720px);
  overflow: auto;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 1rem 1rem 1.2rem;
  box-shadow: var(--shadow);
}
.admin-head { display: flex; justify-content: space-between; align-items: center; gap: 0.7rem; }
.admin-head h2 { margin: 0; font-size: 1.15rem; }
.admin-sheet h3 { margin: 1rem 0 0.5rem; font-size: 0.88rem; color: var(--muted); }
.admin-toggle { display: flex; align-items: center; gap: 0.55rem; margin-top: 0.9rem; }
.admin-users { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.45rem; }
.admin-users li {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  align-items: center;
  justify-content: space-between;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.55rem 0.7rem;
}
.admin-users .meta { display: flex; flex-wrap: wrap; gap: 0.35rem; align-items: center; }
.admin-users .actions { display: flex; flex-wrap: wrap; gap: 0.35rem; }
.admin-users .btn { padding: 0.35rem 0.65rem; font-size: 0.82rem; }
.status-off { color: var(--danger); font-size: 0.78rem; }
.status-on { color: var(--muted); font-size: 0.78rem; }

@media (max-width: 720px) {
  .admin-panel { place-items: end stretch; padding: 0; }
  .admin-sheet { width: 100%; border-radius: 20px 20px 0 0; }
}