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

body {
  font-family: 'Helvetica Neue', Arial, 'Hiragino Kaku Gothic ProN', sans-serif;
  background: #f5f5f5;
  color: #333;
  line-height: 1.7;
}

header {
  background: #fff;
  border-bottom: 1px solid #e0e0e0;
  padding: 1rem 0;
}

.header-inner {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.logo {
  font-size: 1.2rem;
  font-weight: bold;
  color: #1a73e8;
  text-decoration: none;
}

main {
  max-width: 800px;
  margin: 2rem auto;
  padding: 0 1.5rem;
}

h1 {
  font-size: 1.8rem;
  font-weight: bold;
  margin-bottom: 0.5rem;
}

.description {
  color: #666;
  margin-bottom: 1.5rem;
}

.tabs {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.tab {
  padding: 0.6rem 1.2rem;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  background: #fff;
  cursor: pointer;
  font-size: 0.95rem;
  color: #666;
  transition: all 0.2s;
}

.tab:hover {
  background: #f0f4ff;
  color: #1a73e8;
}

.tab.active {
  background: #1a73e8;
  color: #fff;
  border-color: #1a73e8;
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

.card {
  background: #fff;
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  border: 1px solid #e0e0e0;
}

.input-group {
  margin-bottom: 1.2rem;
}

.input-group label {
  display: block;
  font-size: 0.875rem;
  color: #666;
  margin-bottom: 0.4rem;
}

.input-group input[type=date],
.input-group input[type=number] {
  width: 100%;
  padding: 0.6rem 0.8rem;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  font-size: 1rem;
  color: #333;
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 0.7rem 2rem;
  background: #1a73e8;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
}

.btn:hover {
  background: #1557b0;
}

.result-area {
  margin-top: 1rem;
}

.metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.metric {
  background: #fff;
  border-radius: 12px;
  padding: 1.2rem;
  border: 1px solid #e0e0e0;
  text-align: center;
}

.metric-label {
  font-size: 0.8rem;
  color: #666;
  margin-bottom: 0.5rem;
}

.metric-value {
  font-size: 1.3rem;
  font-weight: bold;
}

.metric-value.highlight {
  color: #1a73e8;
}

.info-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.info-table th {
  text-align: left;
  padding: 0.6rem 0.8rem;
  color: #666;
  font-weight: normal;
  border-bottom: 1px solid #f0f0f0;
  width: 40%;
}

.info-table td {
  padding: 0.6rem 0.8rem;
  border-bottom: 1px solid #f0f0f0;
  font-weight: 500;
}

footer {
  text-align: center;
  padding: 2rem;
  color: #999;
  font-size: 0.875rem;
}

@media (max-width: 600px) {
  .metrics {
    grid-template-columns: 1fr;
  }

  h1 {
    font-size: 1.4rem;
  }

  .tabs {
    flex-wrap: wrap;
  }
}

footer a {
  color: #999;
  text-decoration: none;
  margin: 0 0.5rem;
}

footer a:hover {
  color: #1a73e8;
}

footer p {
  margin-bottom: 0.3rem;
}