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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #f0f4f8;
  color: #333;
  min-height: 100vh;
}

.container {
  max-width: 640px;
  margin: 0 auto;
  padding: 16px;
}

h1 {
  font-size: 1.5rem;
  color: #2c5282;
  margin-bottom: 16px;
  text-align: center;
}

h2 {
  font-size: 1rem;
  color: #4a6fa5;
  margin-bottom: 12px;
  padding-bottom: 6px;
  border-bottom: 2px solid #e2e8f0;
}

.card {
  background: #fff;
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 16px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.07);
}

.form-group {
  margin-bottom: 12px;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  color: #666;
  margin-bottom: 4px;
}

.form-group input {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid #cbd5e0;
  border-radius: 8px;
  font-size: 1rem;
  color: #333;
  background: #f7fafc;
  transition: border-color 0.2s;
}

.form-group input:focus {
  outline: none;
  border-color: #5b9bd5;
  background: #fff;
}

.form-row {
  display: flex;
  gap: 12px;
}

.form-row .form-group {
  flex: 1;
}

.btn-primary {
  width: 100%;
  padding: 10px;
  background: #5b9bd5;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
}

.btn-primary:hover {
  background: #4a85bc;
}

.stats-grid {
  display: flex;
  gap: 16px;
}

.stat-item {
  flex: 1;
  text-align: center;
  background: #f0f7ff;
  border-radius: 8px;
  padding: 12px;
}

.stat-value {
  font-size: 1.6rem;
  font-weight: bold;
  color: #2c5282;
}

.stat-label {
  font-size: 0.8rem;
  color: #666;
  margin-top: 4px;
}

#sleepChart {
  width: 100%;
  display: block;
}

#recordList {
  list-style: none;
}

#recordList li {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 0;
  border-bottom: 1px solid #f0f0f0;
  gap: 8px;
}

#recordList li:last-child {
  border-bottom: none;
}

.record-main {
  flex: 1;
}

.record-date {
  font-size: 0.85rem;
  color: #888;
}

.record-times {
  font-size: 0.95rem;
  color: #333;
  margin: 2px 0;
}

.record-duration {
  font-weight: bold;
  color: #2c5282;
}

.record-note {
  font-size: 0.8rem;
  color: #999;
}

.record-badge {
  padding: 3px 8px;
  border-radius: 20px;
  font-size: 0.78rem;
  font-weight: bold;
  white-space: nowrap;
}

.badge-good { background: #c6f6d5; color: #276749; }
.badge-ok   { background: #fef3c7; color: #92400e; }
.badge-bad  { background: #fed7d7; color: #9b2c2c; }

.delete-btn {
  background: none;
  border: none;
  color: #cbd5e0;
  font-size: 1.1rem;
  cursor: pointer;
  padding: 4px;
  transition: color 0.2s;
}

.delete-btn:hover {
  color: #e53e3e;
}

.empty-msg {
  text-align: center;
  color: #aaa;
  padding: 24px 0;
  font-size: 0.9rem;
}

@media (max-width: 400px) {
  h1 { font-size: 1.3rem; }
  .stat-value { font-size: 1.3rem; }
}