body {
  font-family: 'Segoe UI', 'Microsoft YaHei', 'PingFang SC', 'Noto Sans CJK SC', 'WenQuanYi Micro Hei', Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f5f5f5;
}

.container {
  width: 400px;
  padding: 20px;
  background-color: #fff;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  border-radius: 10px;
}

h1 {
  font-size: 20px;
  color: #333;
  margin-top: 0;
  margin-bottom: 20px;
  text-align: center;
}

.input-group {
  margin-bottom: 15px;
}

label {
  display: block;
  margin-bottom: 5px;
  font-weight: 500;
  color: #555;
}

input[type="number"],
input[type="text"],
input[type="password"],
select {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid #ddd;
  border-radius: 4px;
  font-size: 14px;
  box-sizing: border-box;
  transition: border-color 0.2s;
}

input[type="number"]:focus,
input[type="text"]:focus,
input[type="password"]:focus,
select:focus {
  border-color: #4d90fe;
  outline: none;
}

input::placeholder {
  color: #999;
}

button {
  display: block;
  width: 100%;
  padding: 10px;
  background-color: #4285f4;
  color: white;
  border: none;
  border-radius: 4px;
  font-size: 16px;
  cursor: pointer;
  margin-bottom: 20px;
  transition: background-color 0.2s, opacity 0.2s;
}

button:hover { background-color: #3367d6; }
button:disabled { background-color: #ccc; cursor: not-allowed; opacity: 0.6; }
button:active:not(:disabled) { transform: translateY(1px); }

.result-container {
  background-color: #f9f9f9;
  border: 1px solid #eee;
  border-radius: 4px;
  padding: 15px;
  margin-bottom: 15px;
  min-height: 50px;
}

.result-item { margin-bottom: 8px; }
.result-title { font-weight: bold; margin-bottom: 5px; }
.error { color: #d32f2f; font-weight: bold; }
.success { color: #388e3c; }

/* Simple results table */
.results-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.results-table th, .results-table td { border: 1px solid #eee; padding: 6px 8px; text-align: right; }
.results-table th { background: #fafafa; text-align: center; }
.results-table td.label { text-align: left; }
.muted { color: #666; font-size: 12px; }

.formula-container { font-size: 12px; color: #666; border-top: 1px solid #eee; padding-top: 15px; }
.formula-container p { margin: 5px 0; }

.auth-form { margin-top: 10px; animation: fadeIn 0.3s ease-in; }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

.error-message { padding: 10px; margin-bottom: 15px; border-radius: 4px; font-size: 14px; text-align: center; animation: slideDown 0.3s ease-out; }
@keyframes slideDown { from { opacity: 0; transform: translateY(-10px);} to { opacity: 1; transform: translateY(0);} }
.error-message.error { background-color: #ffebee; color: #d32f2f; border: 1px solid #ef9a9a; }
.error-message.success { background-color: #e8f5e9; color: #388e3c; border: 1px solid #a5d6a7; }

.switch-link { text-align: center; font-size: 14px; color: #666; margin-top: 15px; }
.switch-link a { color: #4285f4; text-decoration: none; font-weight: 500; transition: color 0.2s; }
.switch-link a:hover { text-decoration: underline; color: #3367d6; }

.user-info { display: flex; justify-content: space-between; align-items: center; padding: 10px 0; margin-bottom: 15px; border-bottom: 1px solid #eee; font-size: 14px; color: #555; }
.user-info span { font-weight: 500; }
#username-display { color: #4285f4; font-weight: 600; }
.logout-btn { padding: 6px 12px; background-color: #f44336; color: white; border: none; border-radius: 4px; font-size: 14px; cursor: pointer; transition: background-color 0.2s, transform 0.1s; width: auto; margin: 0; }
.logout-btn:hover { background-color: #d32f2f; }
.logout-btn:active { transform: translateY(1px); }

/* Quota UI */
.quota-bar { display:flex; gap:10px; align-items:center; justify-content:flex-end; margin:-5px 0 10px; font-size:13px; color:#444; }
.quota-topup-btn { width:auto; padding:6px 10px; background:#6a9efc; border-radius:4px; font-size:13px; }
.quota-topup-btn:hover { background:#4f84f0; }

.quota-modal.hidden { display:none; }
.quota-modal { position: fixed; inset:0; z-index: 9999; }
.quota-modal-backdrop { position:absolute; inset:0; background:rgba(0,0,0,0.35); }
.quota-modal-content { position:absolute; left:50%; top:50%; transform:translate(-50%,-50%); width: 280px; background:#fff; border-radius:8px; box-shadow:0 8px 30px rgba(0,0,0,.2); padding:16px; }
.quota-modal-title { font-weight:600; margin-bottom:10px; text-align:center; }
.quota-packages { display:flex; gap:10px; justify-content:space-between; margin:10px 0; }
.quota-pack { flex:1; padding:8px; background:#eef3ff; border:1px solid #c9d8ff; border-radius:6px; cursor:pointer; }
.quota-pack:hover { background:#e0eaff; }
.quota-modal-actions { text-align:center; }
.quota-close { width:auto; padding:6px 12px; background:#ddd; color:#333; }
.quota-notes { font-size:12px; color:#666; line-height:1.6; margin:6px 0 10px; }
.quota-notes ul { margin:6px 0 0 18px; padding:0; }
.quota-notes li { list-style: disc; margin: 2px 0; }
.quota-notes-title { font-weight:600; color:#333; margin-bottom:4px; }

.quota-toast.hidden { display:none; }
.quota-toast { position: fixed; left:50%; bottom: 20px; transform: translateX(-50%); background: rgba(0,0,0,0.8); color:#fff; padding:8px 12px; border-radius:16px; font-size:12px; z-index:10000; }

/* Home tool navigation */
.home-subtitle {
  text-align:center;
  margin:0 0 16px;
  font-size:14px;
  color:#666;
}

.tool-card {
  background: linear-gradient(135deg, #eef2ff, #dde7ff);
  border-radius: 12px;
  padding: 12px;
  box-shadow: 0 4px 16px rgba(83, 109, 254, 0.15);
}

.tool-card-header {
  display:flex;
  align-items:center;
  gap:8px;
  margin-bottom:10px;
  font-weight:600;
  color:#374151;
}

.tool-card-icon {
  font-size:16px;
}

.tool-card-title {
  font-size:15px;
}

.tool-list {
  display:flex;
  flex-direction:column;
  gap:8px;
}

.tool-item {
  display:flex;
  align-items:center;
  gap:8px;
  padding:8px 10px;
  border-radius:8px;
  background:#f7f9ff;
  text-decoration:none;
  color:#374151;
  font-size:14px;
  border:1px solid transparent;
  transition: background 0.15s, transform 0.05s, border-color 0.15s;
}

.tool-item-icon {
  width:20px;
  text-align:center;
}

.tool-item:hover {
  background:#e8efff;
  border-color:#a5b4fc;
  transform:translateY(-1px);
}

.tool-item-text {
  flex:1;
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
}

/* Top nav for calculators */
.tool-nav {
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:10px;
  padding:4px 0 10px;
  border-bottom:1px solid #eee;
  margin-bottom:10px;
}

.tool-nav-tabs {
  display:flex;
  gap:8px;
  flex-wrap:wrap;
}

.tool-nav-tab {
  padding:6px 10px;
  border-radius:6px;
  background:#f3f4ff;
  font-size:13px;
  color:#374151;
  text-decoration:none;
  border:1px solid transparent;
  white-space:nowrap;
}

.tool-nav-tab:hover {
  background:#e0e7ff;
  border-color:#a5b4fc;
}

.tool-nav-tab.active {
  background:#4285f4;
  color:#fff;
  border-color:#3367d6;
}

.tool-nav-home {
  font-size:13px;
  color:#4285f4;
  text-decoration:none;
}

.tool-nav-home:hover {
  text-decoration:underline;
}

/* RFI calculator */
.section-title-strong {
  margin:14px 0 8px;
  font-weight:600;
  color:#374151;
  border-left:3px solid #22c55e;
  padding-left:6px;
  font-size:14px;
}

.btn-row {
  display:flex;
  gap:10px;
  margin-top:10px;
  margin-bottom:15px;
}

.btn-row button {
  flex:1;
  margin-bottom:0;
}

.btn-secondary {
  background-color:#e5e7eb;
  color:#374151;
}

.btn-secondary:hover {
  background-color:#d1d5db;
}

/* Filter calculator diagrams */
.diagram-row {
  display:flex;
  align-items:stretch;
  gap:10px;
  margin-bottom:10px;
  flex-wrap:wrap;
}

.diagram-box {
  flex:1;
  min-height:120px;
  background:#ffffff;
  border:1px solid #eee;
  border-radius:6px;
  display:flex;
  align-items:center;
  justify-content:center;
  overflow:hidden;
}

.diagram-box svg {
  width:100%;
  height:100%;
}