:root {
  --color-primary: #1a73e8;
  --color-primary-light: #e8f0fe;
  --color-bg: #f5f5f5;
  --color-card: #ffffff;
  --color-text: #202124;
  --color-text-secondary: #5f6368;
  --color-border: #dadce0;
  --color-border-focus: #1a73e8;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08), 0 4px 16px rgba(0, 0, 0, 0.06);
}

html, body, main, header, footer {
  padding: 0px;
  margin: 0px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  display: flex;
  justify-content: center;
  padding: 16px 16px 0;
}

main {
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 24px 16px 40px;
}

footer {
  display: flex;
  justify-content: center;
  padding: 16px;
}

div#app {
  width: 100%;
  max-width: 480px;
}

.converter-card {
  background: var(--color-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.card-title {
  font-size: 22px;
  font-weight: 600;
  text-align: center;
  color: var(--color-text);
  margin: 0 0 4px;
}

.converter-row {
  display: flex;
  align-items: center;
  gap: 12px;
}

.unit-label {
  flex-shrink: 0;
  width: 44px;
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text-secondary);
  text-align: right;
}

.unit-input {
  flex: 1;
  height: 44px;
  padding: 0 14px;
  font-size: 16px;
  border: 2px solid var(--color-border);
  border-radius: 8px;
  outline: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
  box-sizing: border-box;
  color: var(--color-text);
  background: #fafafa;
}

.unit-input:focus {
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px var(--color-primary-light);
  background: #fff;
}

.unit-input::placeholder {
  color: #bdc1c6;
}

.clear-btn {
  align-self: center;
  padding: 8px 32px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text-secondary);
  background: #f1f3f4;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.2s ease;
  margin-top: 4px;
}

.clear-btn:hover {
  background: #e8eaed;
}

.clear-btn:active {
  background: #dadce0;
}

.info-section {
  background: var(--color-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px 28px;
  margin-top: 20px;
}

.info-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--color-text);
  margin: 0 0 12px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-primary-light);
}

.info-text {
  font-size: 14px;
  line-height: 1.8;
  color: var(--color-text-secondary);
  margin: 0;
}

.scenario-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.scenario-list li {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-text-secondary);
  padding: 8px 12px;
  background: #fafafa;
  border-radius: 8px;
  border-left: 3px solid var(--color-primary);
}

.scenario-list li strong {
  color: var(--color-text);
}

@media (max-width: 768px) {
  .converter-card {
    padding: 24px 18px;
  }

  .card-title {
    font-size: 20px;
  }

  .unit-label {
    width: 36px;
    font-size: 14px;
  }

  .unit-input {
    height: 42px;
    font-size: 15px;
    padding: 0 10px;
  }
}