:root {
  --primary: #4A90D9;
  --primary-light: #6BA5E7;
  --primary-dark: #3A7BC8;
  --success: #52C41A;
  --success-light: #73D13D;
  --warning: #FAAD14;
  --warning-light: #FFC53D;
  --danger: #FF4D4F;
  --danger-light: #FF7875;
  --text: #1F2937;
  --text-secondary: #6B7280;
  --bg: #F0F2F5;
  --card-bg: #FFFFFF;
  --border: #E5E7EB;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.12);
  --radius: 12px;
  --radius-sm: 8px;
  --font: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", system-ui, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Consolas", monospace;
}

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

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.6;
}

/* Navigation */
#app-nav {
  background: var(--card-bg);
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-inner {
  max-width: 960px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  padding: 0 20px;
  height: 56px;
  gap: 24px;
}

.nav-brand {
  font-size: 18px;
  font-weight: 700;
  color: var(--primary);
  white-space: nowrap;
}

.nav-tabs {
  display: flex;
  gap: 4px;
  flex: 1;
  justify-content: center;
}

.nav-tab {
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}

.nav-tab:hover {
  background: var(--bg);
  color: var(--text);
}

.nav-tab.active {
  background: var(--primary);
  color: #fff;
}

.nav-logout {
  font-size: 14px;
  color: var(--text-secondary);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  transition: all 0.2s;
}

.nav-logout:hover {
  background: var(--danger);
  color: #fff;
}

/* Main content */
#app-root {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px 20px;
}

/* Toast */
#toast-container {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 9999;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  pointer-events: none;
}

.toast {
  background: var(--text);
  color: #fff;
  padding: 10px 24px;
  border-radius: 24px;
  font-size: 14px;
  animation: toastIn 0.3s ease;
  pointer-events: auto;
  box-shadow: var(--shadow-lg);
}

.toast-fade-out {
  animation: toastOut 0.3s ease forwards;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateY(-12px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes toastOut {
  from { opacity: 1; transform: translateY(0); }
  to { opacity: 0; transform: translateY(-12px); }
}

/* Modal overlay */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.45);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.modal {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 28px;
  width: 90%;
  max-width: 440px;
  box-shadow: var(--shadow-lg);
  animation: modalIn 0.25s ease;
}

@keyframes modalIn {
  from { opacity: 0; transform: scale(0.95) translateY(8px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}

.modal h3 {
  font-size: 18px;
  margin-bottom: 20px;
  color: var(--text);
}

.modal label {
  display: block;
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 6px;
  margin-top: 16px;
}

.modal label:first-of-type {
  margin-top: 0;
}

.modal input[type="text"],
.modal textarea {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-family: var(--font);
  outline: none;
  transition: border-color 0.2s;
}

.modal input[type="text"]:focus,
.modal textarea:focus {
  border-color: var(--primary);
}

.modal textarea {
  resize: vertical;
  min-height: 60px;
}

.modal-actions {
  display: flex;
  gap: 12px;
  justify-content: flex-end;
  margin-top: 24px;
}

/* Buttons */
.btn {
  padding: 8px 20px;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-family: var(--font);
  cursor: pointer;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

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

.btn-secondary {
  background: var(--bg);
  color: var(--text);
}

.btn-secondary:hover {
  background: var(--border);
}

.btn-danger {
  background: var(--danger);
  color: #fff;
}

.btn-danger:hover {
  background: #e04344;
}

/* Range slider */
.range-container {
  display: flex;
  align-items: center;
  gap: 12px;
}

.range-container input[type="range"] {
  flex: 1;
  accent-color: var(--primary);
  height: 6px;
}

.range-value {
  font-size: 16px;
  font-weight: 600;
  color: var(--primary);
  min-width: 60px;
  text-align: center;
}

/* Suggestion dropdown */
.suggest-wrap {
  position: relative;
}

.suggest-list {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-top: none;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
  max-height: 160px;
  overflow-y: auto;
  z-index: 10;
  box-shadow: var(--shadow);
}

.suggest-item {
  padding: 8px 12px;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.15s;
}

.suggest-item:hover {
  background: var(--bg);
}

/* Summary stats */
.stat-card {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}

.stat-item {
  background: var(--card-bg);
  border-radius: var(--radius-sm);
  padding: 16px 20px;
  flex: 1;
  min-width: 140px;
  box-shadow: var(--shadow);
}

.stat-label {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 4px;
}

.stat-value {
  font-size: 22px;
  font-weight: 700;
}

.stat-value.productive { color: var(--success); }
.stat-value.interruption { color: var(--danger); }
.stat-value.other { color: var(--primary); }

/* Responsive */
@media (max-width: 640px) {
  .nav-inner {
    flex-wrap: wrap;
    height: auto;
    padding: 12px 16px;
    gap: 8px;
  }
  .nav-tabs {
    order: 3;
    width: 100%;
    justify-content: space-around;
  }
  .nav-tab {
    font-size: 13px;
    padding: 6px 10px;
  }
  #app-root {
    padding: 16px;
  }
}