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

:root {
  --bg-primary: #0f1117;
  --bg-secondary: #161822;
  --bg-card: #1b1e2c;
  --bg-card-hover: #212538;
  --border: #2a2d3d;
  --text-primary: #e4e6ed;
  --text-secondary: #9497a5;
  --text-muted: #6b6e7d;
  --accent: #4f8eff;
  --accent-hover: #6ba3ff;
  --accent-dim: rgba(79, 142, 255, 0.15);
  --success: #34c77b;
  --warning: #f5a623;
  --danger: #f54c4c;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow: 0 2px 8px rgba(0,0,0,0.3);
  --transition: 0.2s ease;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
}

/* ====== Login Page ====== */
.login-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  background: radial-gradient(ellipse at center, #1a1f35 0%, var(--bg-primary) 70%);
}

.login-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 48px 40px;
  width: 420px;
  max-width: 90vw;
  box-shadow: 0 8px 32px rgba(0,0,0,0.4);
}

.login-header {
  text-align: center;
  margin-bottom: 36px;
}

.login-header .logo {
  width: 56px;
  height: 56px;
  background: var(--accent-dim);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  font-size: 28px;
}

.login-header h1 {
  font-size: 22px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.login-header p {
  font-size: 13px;
  color: var(--text-secondary);
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.form-group input {
  width: 100%;
  padding: 12px 16px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-primary);
  font-size: 15px;
  transition: border-color var(--transition);
  outline: none;
}

.form-group input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

.form-group input::placeholder {
  color: var(--text-muted);
}

.password-wrapper {
  position: relative;
}

.password-wrapper input {
  padding-right: 48px;
}

.password-toggle {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 14px;
  padding: 4px;
  line-height: 1;
}

.password-toggle:hover {
  color: var(--text-secondary);
}

.login-btn {
  width: 100%;
  padding: 12px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition);
  margin-top: 8px;
}

.login-btn:hover {
  background: var(--accent-hover);
}

.login-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.error-msg {
  background: rgba(245, 76, 76, 0.1);
  border: 1px solid rgba(245, 76, 76, 0.3);
  border-radius: var(--radius);
  padding: 10px 14px;
  color: var(--danger);
  font-size: 13px;
  margin-bottom: 16px;
  display: none;
}

.error-msg.visible {
  display: block;
}

/* ====== Dashboard Layout ====== */
.dashboard-container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* Top Nav */
.navbar {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-shrink: 0;
}

.nav-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.nav-logo {
  width: 32px;
  height: 32px;
  background: var(--accent-dim);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
}

.nav-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  white-space: nowrap;
}

.nav-center {
  display: flex;
  align-items: center;
  gap: 16px;
}

.status-indicator {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--text-secondary);
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--success);
}

.status-dot.warning { background: var(--warning); }
.status-dot.critical { background: var(--danger); }
.status-dot.no_data { background: var(--text-muted); }

.nav-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

.nav-time {
  font-size: 13px;
  color: var(--text-secondary);
  font-variant-numeric: tabular-nums;
}

.logout-btn {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 6px 14px;
  border-radius: var(--radius);
  font-size: 13px;
  cursor: pointer;
  transition: all var(--transition);
  margin-left: 8px;
}

.logout-btn:hover {
  color: var(--text-primary);
  border-color: var(--danger);
}

.chpwd-btn {
  border-color: transparent;
}

.chpwd-btn:hover {
  border-color: var(--accent);
}

/* Summary Bar */
.summary-bar {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
  padding: 16px 24px;
  flex-shrink: 0;
}

.summary-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  display: flex;
  align-items: center;
  gap: 14px;
}

.summary-icon {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  flex-shrink: 0;
}

.summary-icon.cpu { background: rgba(79,142,255,0.15); color: var(--accent); }
.summary-icon.mem { background: rgba(52,199,123,0.15); color: var(--success); }
.summary-icon.disk { background: rgba(245,166,35,0.15); color: var(--warning); }
.summary-icon.net { background: rgba(168,85,247,0.15); color: #a855f7; }

.summary-info {
  min-width: 0;
}

.summary-label {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 2px;
}

.summary-value {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-primary);
  font-variant-numeric: tabular-nums;
}

.summary-unit {
  font-size: 13px;
  font-weight: 400;
  color: var(--text-secondary);
}

/* Time Range Selector */
.time-range-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px 12px;
  flex-shrink: 0;
}

.time-range-label {
  font-size: 13px;
  color: var(--text-secondary);
}

.time-range-btns {
  display: flex;
  gap: 4px;
}

.time-btn {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 6px 14px;
  border-radius: var(--radius);
  font-size: 13px;
  cursor: pointer;
  transition: all var(--transition);
}

.time-btn:hover {
  color: var(--text-primary);
  border-color: var(--text-muted);
}

.time-btn.active {
  background: var(--accent-dim);
  border-color: var(--accent);
  color: var(--accent);
}

/* Charts Grid */
.charts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(420px, 1fr));
  gap: 16px;
  padding: 0 24px 24px;
  flex: 1;
}

.chart-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition);
  cursor: pointer;
}

.chart-card:hover {
  border-color: var(--text-muted);
  box-shadow: var(--shadow);
}

.chart-card.expanded {
  grid-column: 1 / -1;
  cursor: default;
}

.chart-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px 12px;
}

.chart-card-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.chart-card-title .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}

.chart-card-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.expand-btn {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 16px;
  padding: 4px;
  line-height: 1;
  transition: color var(--transition);
}

.expand-btn:hover {
  color: var(--text-primary);
}

.chart-card-body {
  padding: 0 12px 16px;
  position: relative;
  height: 240px;
}

.chart-card.expanded .chart-card-body {
  height: 400px;
}

.chart-card-footer {
  padding: 8px 20px 14px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border);
  font-size: 12px;
  color: var(--text-muted);
}

/* Expanded detail section */
.chart-detail {
  display: none;
  padding: 0 20px 20px;
  border-top: 1px solid var(--border);
}

.chart-card.expanded .chart-detail {
  display: block;
}

.detail-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

.detail-table th {
  text-align: left;
  color: var(--text-muted);
  font-weight: 500;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
}

.detail-table td {
  padding: 8px 12px;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border);
  font-variant-numeric: tabular-nums;
}

.detail-table tr:last-child td {
  border-bottom: none;
}

.detail-table tr:hover td {
  background: var(--bg-secondary);
}

/* Loading & empty states */
.loading-overlay {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  color: var(--text-muted);
  font-size: 13px;
}

.spinner {
  width: 24px;
  height: 24px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin-right: 10px;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.empty-state {
  text-align: center;
  padding: 48px 24px;
  color: var(--text-muted);
}

.empty-state .icon {
  font-size: 48px;
  margin-bottom: 12px;
}

/* Toast message */
.toast {
  position: fixed;
  top: 20px;
  right: 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 20px;
  color: var(--text-primary);
  font-size: 14px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.4);
  z-index: 9999;
  transform: translateX(120%);
  transition: transform 0.3s ease;
}

.toast.show {
  transform: translateX(0);
}

.toast.error {
  border-color: var(--danger);
}

.toast.success {
  border-color: var(--success);
}

/* Modal */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  z-index: 1000;
  align-items: center;
  justify-content: center;
}

.modal-overlay.visible {
  display: flex;
}

.modal {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  width: 400px;
  max-width: 90vw;
  box-shadow: 0 12px 40px rgba(0,0,0,0.5);
}

.modal h2 {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.modal .modal-subtitle {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.modal .form-group {
  margin-bottom: 20px;
}

.modal .form-group label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.modal .form-group input {
  width: 100%;
  padding: 10px 14px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-primary);
  font-size: 14px;
  outline: none;
  transition: border-color var(--transition);
}

.modal .form-group input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

.modal-actions {
  display: flex;
  gap: 10px;
  justify-content: flex-end;
  margin-top: 8px;
}

.modal-actions button {
  padding: 8px 20px;
  border-radius: var(--radius);
  font-size: 14px;
  cursor: pointer;
  transition: all var(--transition);
}

.btn-cancel {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  color: var(--text-secondary);
}

.btn-cancel:hover {
  color: var(--text-primary);
}

.btn-primary {
  background: var(--accent);
  border: 1px solid var(--accent);
  color: #fff;
  font-weight: 500;
}

.btn-primary:hover {
  background: var(--accent-hover);
}

.modal .error-msg {
  margin-bottom: 12px;
}

/* Responsive */
@media (max-width: 768px) {
  .charts-grid {
    grid-template-columns: 1fr;
  }
  .summary-bar {
    grid-template-columns: repeat(2, 1fr);
  }
  .nav-center {
    display: none;
  }
}