:root {
  --bg: #0d1117;
  --bg-soft: #161b22;
  --bg-card: #1c2128;
  --bg-elevated: #22272e;
  --bg-input: #1a1f26;
  --border: #2d333b;
  --border-soft: #21262d;
  --text: #e6edf3;
  --text-muted: #768390;
  --text-faint: #636c76;
  --primary: #5cadff;
  --primary-soft: rgba(92, 173, 255, 0.14);
  --primary-hover: #79c2ff;
  --accent: #a371f7;
  --green: #6adb95;
  --red: #f76d8d;
  --orange: #f7a878;
  --bubble-me: linear-gradient(135deg, var(--primary), var(--accent));
  --radius: 14px;
  --radius-sm: 10px;
  --radius-xs: 7px;
  --shadow-sm: 0 1px 0 rgba(255,255,255,0.04) inset, 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.35);
  --shadow-glow: 0 0 0 1px var(--border), 0 8px 32px rgba(0,0,0,0.4), 0 0 40px rgba(92,173,255,0.06);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }

body {
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(92,173,255,0.07), transparent 60%),
    radial-gradient(900px 500px at -10% 20%, rgba(163,113,247,0.05), transparent 55%),
    var(--bg);
  color: var(--text);
  font-family: "Inter", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 8px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-faint); }

button { font-family: inherit; cursor: pointer; }
input, textarea { font-family: inherit; }
[hidden] { display: none !important; }

/* ===== Auth ===== */
.auth {
  display: grid;
  place-items: center;
  height: 100%;
  padding: 24px;
}
.auth-card {
  width: 100%;
  max-width: 400px;
  background: linear-gradient(180deg, rgba(255,255,255,0.018), transparent), var(--bg-soft);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow-glow);
}
.auth-head { text-align: center; margin-bottom: 24px; }
.auth-logo {
  width: 52px; height: 52px;
  margin: 0 auto 14px;
  display: grid; place-items: center;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff; font-size: 22px;
  box-shadow: 0 6px 20px rgba(92,173,255,0.35);
}
.auth-card h1 { font-size: 26px; font-weight: 700; letter-spacing: .3px; }
.auth-sub { color: var(--text-muted); font-size: 13px; margin-top: 4px; }

.tabs {
  display: flex; gap: 4px;
  background: var(--bg-elevated);
  padding: 4px;
  border-radius: 10px;
  margin-bottom: 18px;
}
.tab {
  flex: 1; padding: 8px 12px;
  border: 0; background: transparent;
  color: var(--text-muted); font-size: 14px; font-weight: 500;
  border-radius: 7px;
  transition: all .18s;
}
.tab.active {
  background: var(--bg-card);
  color: var(--text);
  box-shadow: var(--shadow-sm);
}

.field { display: block; margin-bottom: 14px; }
.field span {
  display: block;
  font-size: 12px;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 6px;
  letter-spacing: .2px;
}
.field input {
  width: 100%;
  padding: 11px 14px;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 9px;
  color: var(--text);
  font-size: 14px;
  outline: none;
  transition: border-color .18s, box-shadow .18s;
}
.field input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-soft);
}

.btn-primary {
  width: 100%;
  padding: 11px 16px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  border: 0;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 600;
  transition: transform .1s, box-shadow .18s, filter .18s;
}
.btn-primary:hover { box-shadow: 0 6px 18px rgba(92,173,255,0.32); filter: brightness(1.05); }
.btn-primary:active { transform: translateY(1px); }
.btn-primary:disabled { opacity: .5; cursor: not-allowed; }

.auth-error {
  background: rgba(247,109,141,0.12);
  border: 1px solid rgba(247,109,141,0.3);
  color: var(--red);
  padding: 9px 12px;
  border-radius: 8px;
  font-size: 13px;
  margin-bottom: 12px;
}

/* ===== Chat Layout ===== */
.chat {
  display: grid;
  grid-template-columns: 280px 1fr;
  height: 100%;
}
.sidebar {
  background: var(--bg-soft);
  border-right: 1px solid var(--border-soft);
  display: flex;
  flex-direction: column;
  min-height: 0;
}
.sidebar-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 18px;
  border-bottom: 1px solid var(--border-soft);
}
.logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 16px; }
.logo-icon {
  display: grid; place-items: center;
  width: 28px; height: 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff; font-size: 12px;
  box-shadow: 0 3px 12px rgba(92,173,255,0.32);
}

.icon-btn {
  width: 32px; height: 32px;
  display: grid; place-items: center;
  background: transparent; border: 0;
  color: var(--text-muted);
  border-radius: 8px;
  font-size: 16px;
  transition: background .18s, color .18s;
}
.icon-btn:hover { background: var(--bg-elevated); color: var(--text); }

.online-list {
  flex: 1;
  overflow-y: auto;
  padding: 12px 10px;
}
.online-list .empty-online {
  color: var(--text-faint);
  text-align: center;
  padding: 24px 12px;
  font-size: 13px;
}
.online-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  border-radius: 9px;
  cursor: default;
  transition: background .15s;
}
.online-item.me { background: var(--primary-soft); }
.online-item:hover { background: var(--bg-elevated); }
.online-item .avatar {
  width: 32px; height: 32px; flex-shrink: 0;
}
.online-item .nm { font-size: 14px; color: var(--text); font-weight: 500; }
.online-item .nm .me-tag {
  color: var(--text-faint); font-size: 11px; margin-left: 4px;
  font-weight: 400;
}
.online-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 6px var(--green);
  margin-left: auto;
  flex-shrink: 0;
}

.sidebar-foot {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  border-top: 1px solid var(--border-soft);
}
.me-meta { flex: 1; min-width: 0; }
.me-name { font-size: 14px; font-weight: 500; display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.link-btn {
  background: transparent; border: 0;
  color: var(--primary); font-size: 12px; padding: 0;
  cursor: pointer;
}
.link-btn:hover { text-decoration: underline; }

/* ===== Main ===== */
.main {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
}
.chat-head {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-soft);
  background: linear-gradient(180deg, rgba(255,255,255,0.022), transparent), var(--bg-soft);
}
.back-btn { display: none; }
.room-name { font-size: 17px; font-weight: 600; }
.online-count {
  color: var(--text-faint);
  font-size: 13px;
  padding: 4px 10px;
  background: var(--bg-elevated);
  border-radius: 999px;
}

.messages {
  flex: 1;
  overflow-y: auto;
  padding: 18px 22px 8px;
  min-height: 0;
}
.load-more-wrap { text-align: center; padding: 8px 0 18px; }
.load-more {
  background: var(--bg-elevated);
  border: 1px solid var(--border-soft);
  color: var(--text-muted);
  padding: 7px 18px;
  border-radius: 999px;
  font-size: 13px;
  transition: all .18s;
}
.load-more:hover { color: var(--text); border-color: var(--primary); }

.msg-group {
  margin-bottom: 14px;
  display: flex;
  gap: 10px;
  align-items: flex-start;
  animation: fadeUp .25s ease;
}
.msg-group.me { flex-direction: row-reverse; }

.msg-group .avatar { width: 36px; height: 36px; flex-shrink: 0; }
.msg-body { display: flex; flex-direction: column; min-width: 0; max-width: min(75%, 620px); }
.msg-group.me .msg-body { align-items: flex-end; }

.msg-meta {
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin-bottom: 5px;
}
.msg-name { font-size: 12px; font-weight: 600; color: var(--text-muted); }
.msg-time { font-size: 11px; color: var(--text-faint); }

.bubble {
  padding: 9px 14px;
  background: var(--bg-card);
  border: 1px solid var(--border-soft);
  border-radius: 14px 14px 14px 4px;
  color: var(--text);
  font-size: 14px;
  line-height: 1.5;
  word-break: break-word;
  white-space: pre-wrap;
  box-shadow: var(--shadow-sm);
  max-width: 100%;
}
.msg-group.me .bubble {
  background: var(--bubble-me);
  color: #fff;
  border-color: transparent;
  border-radius: 14px 14px 4px 14px;
}
.msg-group.me .msg-name { color: rgba(255,255,255,.7); }

.typing {
  padding: 4px 8px 12px;
  font-size: 12px;
  color: var(--text-faint);
  font-style: italic;
  min-height: 22px;
}

/* Composer */
.composer {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  border-top: 1px solid var(--border-soft);
  background: var(--bg-soft);
}
.composer input {
  flex: 1;
  padding: 11px 14px;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--text);
  font-size: 14px;
  outline: none;
  transition: border-color .18s, box-shadow .18s;
}
.composer input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-soft);
}
.send-btn {
  width: auto;
  padding: 10px 22px;
  border-radius: 999px;
}

/* Avatar */
.avatar {
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  font-weight: 700;
  font-size: 14px;
  user-select: none;
  letter-spacing: -.5px;
}

/* Modal */
.modal {
  position: fixed; inset: 0;
  background: rgba(1,4,9,.7);
  backdrop-filter: blur(6px);
  display: grid; place-items: center;
  z-index: 100;
  padding: 20px;
}
.modal-card {
  width: 100%;
  max-width: 380px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-md);
}
.modal-card h3 { margin-bottom: 18px; font-size: 18px; }
.modal-foot { display: flex; gap: 10px; justify-content: flex-end; margin-top: 18px; }
.btn-ghost {
  padding: 9px 16px;
  background: var(--bg-elevated);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  transition: border-color .18s;
}
.btn-ghost:hover { border-color: var(--primary); }
.color-picker {
  display: flex; gap: 8px; flex-wrap: wrap;
}
.color-swatch {
  width: 28px; height: 28px;
  border-radius: 50%;
  cursor: pointer;
  border: 2px solid transparent;
  transition: transform .12s, border-color .18s;
}
.color-swatch:hover { transform: scale(1.1); }
.color-swatch.active { border-color: #fff; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Responsive */
@media (max-width: 860px) {
  .chat { grid-template-columns: 1fr; }
  .sidebar {
    position: fixed; inset: 0 auto 0 0;
    width: 280px; max-width: 85vw;
    z-index: 30;
    transform: translateX(-100%);
    transition: transform .22s ease;
  }
  .sidebar.open { transform: translateX(0); }
  .back-btn { display: grid; }
  .messages { padding: 14px 14px 6px; }
  .msg-body { max-width: 85%; }
  .composer { padding: 10px 12px; }
  #menuBtn { display: grid; }
}