* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg-dark: #1a1a2e;
  --bg-darker: #16213e;
  --bg-accent: #0f3460;
  --green: #4CAF50;
  --green-hover: #45a049;
  --red: #e94560;
  --gold: #FFD700;
  --blue: #4fc3f7;
  --purple: #b388ff;
  --text: #e0e0e0;
  --text-dim: #8a8a9a;
  --border: rgba(15, 52, 96, 0.4);
  --radius: 10px;
}

body {
  font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
  background: var(--bg-dark);
  color: var(--text);
  overflow: hidden;
  height: 100vh;
  user-select: none;
}

/* Titlebar */
.titlebar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 36px;
  background: #111128;
  border-bottom: 1px solid var(--border);
  -webkit-app-region: drag;
  padding: 0 8px;
}
.titlebar-drag {
  display: flex;
  align-items: center;
  gap: 8px;
}
.titlebar-icon { font-size: 14px; }
.titlebar-title { font-size: 12px; color: var(--text-dim); }
.titlebar-controls {
  display: flex;
  -webkit-app-region: no-drag;
}
.tb-btn {
  background: none;
  border: none;
  color: var(--text-dim);
  width: 36px;
  height: 36px;
  font-size: 12px;
  cursor: pointer;
  transition: background 0.15s;
}
.tb-btn:hover { background: rgba(255,255,255,0.1); }
.tb-close:hover { background: var(--red); color: #fff; }

/* App Layout */
.app {
  display: flex;
  height: calc(100vh - 36px);
}

/* Sidebar */
.sidebar {
  width: 220px;
  background: var(--bg-darker);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
}
.sidebar-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 16px;
  border-bottom: 1px solid var(--border);
}
.logo-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--green), #2e7d32);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Press Start 2P', monospace;
  font-size: 16px;
  color: #fff;
}
.logo-name {
  font-weight: 700;
  font-size: 14px;
  color: var(--green);
  display: block;
}
.logo-sub {
  font-size: 10px;
  color: var(--text-dim);
  display: block;
  margin-top: 2px;
}
.sidebar-status {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  font-size: 12px;
  color: var(--text-dim);
  border-bottom: 1px solid var(--border);
}
.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}
.status-dot.online { background: var(--green); box-shadow: 0 0 6px var(--green); }
.status-dot.offline { background: var(--red); }
.sidebar-nav {
  list-style: none;
  padding: 12px 8px;
  flex: 1;
}
.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 13px;
  color: var(--text-dim);
  cursor: pointer;
  transition: all 0.2s;
  margin-bottom: 2px;
}
.nav-item:hover {
  background: rgba(15, 52, 96, 0.4);
  color: var(--text);
}
.nav-item.active {
  background: rgba(76, 175, 80, 0.15);
  color: var(--green);
  border: 1px solid rgba(76, 175, 80, 0.3);
}
.nav-icon { font-size: 16px; }
.sidebar-footer {
  padding: 12px;
  text-align: center;
  font-size: 10px;
  color: var(--text-dim);
  border-top: 1px solid var(--border);
}

/* Content */
.content {
  flex: 1;
  overflow-y: auto;
  padding: 28px 32px;
}
.content::-webkit-scrollbar { width: 6px; }
.content::-webkit-scrollbar-track { background: transparent; }
.content::-webkit-scrollbar-thumb { background: var(--bg-accent); border-radius: 3px; }

/* Pages */
.page { display: none; }
.page.active { display: block; animation: fadeIn 0.2s ease; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: translateY(0); } }

.page-title { font-size: 22px; font-weight: 700; margin-bottom: 4px; }
.page-desc { font-size: 13px; color: var(--text-dim); margin-bottom: 24px; }
.page-header { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 24px; }

/* Card */
.card {
  background: var(--bg-darker);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

/* Form */
.form-group { margin-bottom: 16px; }
.form-group label {
  display: block;
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 6px;
  font-weight: 500;
}
.form-row { display: flex; gap: 16px; }
.form-row .form-group { flex: 1; }
.form-hint { font-size: 11px; color: var(--text-dim); margin-top: 4px; display: block; }

.input {
  width: 100%;
  padding: 10px 14px;
  background: var(--bg-dark);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 13px;
  outline: none;
  transition: border-color 0.2s;
}
.input:focus { border-color: var(--green); }
.input::placeholder { color: #555; }
select.input { cursor: pointer; }

/* Buttons */
.btn {
  padding: 10px 20px;
  border: none;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--green); color: #fff; }
.btn-primary:hover { background: var(--green-hover); }
.btn-secondary { background: var(--bg-accent); color: var(--text); }
.btn-secondary:hover { background: #1a4a7a; }
.btn-danger { background: var(--red); color: #fff; }
.btn-danger:hover { background: #d63050; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* Messages */
.msg {
  margin-top: 12px;
  font-size: 13px;
  min-height: 20px;
}
.msg.error { color: var(--red); }
.msg.success { color: var(--green); }

/* Server Info */
.server-info { margin-top: 20px; }
.server-info h3 {
  font-size: 14px;
  margin-bottom: 12px;
  color: var(--green);
}
.info-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}
.info-item {
  background: var(--bg-dark);
  border-radius: 8px;
  padding: 10px 14px;
}
.info-item .label {
  font-size: 11px;
  color: var(--text-dim);
  margin-bottom: 4px;
}
.info-item .value {
  font-size: 14px;
  font-weight: 600;
}

/* Rooms Grid */
.rooms-grid { display: flex; flex-direction: column; gap: 12px; }
.room-card {
  background: var(--bg-darker);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: border-color 0.2s;
}
.room-card:hover { border-color: rgba(76, 175, 80, 0.4); }
.room-left { display: flex; align-items: center; gap: 14px; }
.room-icon {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: rgba(76, 175, 80, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
}
.room-name { font-weight: 600; font-size: 14px; }
.room-meta { font-size: 11px; color: var(--text-dim); margin-top: 3px; }
.room-right { display: flex; align-items: center; gap: 10px; }
.room-players {
  font-size: 12px;
  color: var(--blue);
  background: rgba(79, 195, 247, 0.1);
  padding: 4px 10px;
  border-radius: 20px;
}
.room-version {
  font-size: 12px;
  color: var(--purple);
  background: rgba(179, 136, 255, 0.1);
  padding: 4px 10px;
  border-radius: 20px;
}
.room-btn-join {
  padding: 6px 14px;
  background: var(--green);
  border: none;
  border-radius: 6px;
  color: #fff;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}
.room-btn-join:hover { background: var(--green-hover); }

/* Empty State */
.empty-state {
  text-align: center;
  padding: 48px 0;
  color: var(--text-dim);
}
.empty-icon { font-size: 48px; display: block; margin-bottom: 12px; }

/* Room Result */
.room-result {
  margin-top: 20px;
  background: var(--bg-dark);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
}
.result-title { font-size: 18px; font-weight: 700; color: var(--green); margin-bottom: 12px; }
.result-room-id {
  font-family: 'Press Start 2P', monospace;
  font-size: 22px;
  color: var(--gold);
  letter-spacing: 2px;
  margin: 16px 0;
}
.result-hint { font-size: 12px; color: var(--text-dim); margin-bottom: 16px; }

/* Join Status */
.join-status { margin-top: 16px; }
.status-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px;
  border-radius: var(--radius);
  background: rgba(76, 175, 80, 0.1);
  border: 1px solid rgba(76, 175, 80, 0.3);
}
.status-emoji { font-size: 28px; }
.status-title { font-weight: 600; font-size: 14px; color: var(--green); }
.status-detail { font-size: 12px; color: var(--text-dim); margin-top: 4px; }
.status-detail strong { color: var(--gold); }

/* About */
.about-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 24px;
}
.about-logo {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--green), #2e7d32);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Press Start 2P', monospace;
  font-size: 22px;
  color: #fff;
}
.about-header h3 { font-size: 18px; }
.about-header p { font-size: 13px; color: var(--text-dim); margin-top: 2px; }
.about-section { margin-top: 20px; }
.about-section h4 { font-size: 14px; margin-bottom: 12px; color: var(--green); }
.about-section p { font-size: 13px; color: var(--text-dim); margin-bottom: 6px; }

.steps { display: flex; flex-direction: column; gap: 12px; }
.step {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: var(--bg-dark);
  border-radius: 8px;
  padding: 14px;
}
.step-num {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: rgba(76, 175, 80, 0.2);
  color: var(--green);
  font-weight: 700;
  font-size: 13px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.step strong { font-size: 13px; display: block; margin-bottom: 3px; }
.step p { font-size: 12px; color: var(--text-dim); }

/* Utility */
.hidden { display: none !important; }

/* Loading spinner */
.spinner {
  display: inline-block;
  width: 16px;
  height: 16px;
  border: 2px solid rgba(255,255,255,0.3);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }