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

#app {
  max-width: 800px;
  margin: 0 auto;
  padding: 20px 16px 40px;
}

#app-title {
  text-align: center;
  font-size: 28px;
  color: #1565C0;
  margin: 0 0 8px 0;
}

#app-subtitle {
  text-align: center;
  font-size: 15px;
  color: #607D8B;
  margin: 0 0 32px 0;
}

#calculator-body {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}

#input-area {
  flex: 1;
  min-width: 280px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.input-card {
  background: #F5F9FF;
  border: 1px solid #BBDEFB;
  border-radius: 12px;
  padding: 20px;
}

.input-card label {
  display: block;
  font-size: 16px;
  font-weight: 600;
  color: #0D47A1;
  margin-bottom: 12px;
}

#weight-input {
  width: 100%;
  height: 44px;
  border: 1px solid #90CAF9;
  border-radius: 8px;
  padding: 0 12px;
  font-size: 16px;
  box-sizing: border-box;
  outline: none;
  transition: border-color 0.2s;
}

#weight-input:focus {
  border-color: #1565C0;
}

#weight-unit-group {
  display: flex;
  gap: 16px;
  margin-top: 10px;
}

.unit-radio {
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  font-size: 14px;
  color: #455A64;
}

.unit-radio input[type="radio"] {
  accent-color: #1565C0;
}

.radio-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.option-radio {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  padding: 10px 12px;
  border: 1px solid #E3F2FD;
  border-radius: 8px;
  transition: background 0.2s, border-color 0.2s;
}

.option-radio:hover {
  background: #E3F2FD;
}

.option-radio input[type="radio"] {
  accent-color: #1565C0;
  flex-shrink: 0;
}

.option-title {
  font-size: 14px;
  font-weight: 600;
  color: #263238;
  min-width: 80px;
}

.option-desc {
  font-size: 12px;
  color: #90A4AE;
}

#calculate-btn {
  width: 100%;
  height: 48px;
  background: linear-gradient(135deg, #42A5F5, #1565C0);
  color: #fff;
  border: none;
  border-radius: 10px;
  font-size: 17px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s;
}

#calculate-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(21, 101, 192, 0.35);
}

#calculate-btn:active {
  transform: translateY(0);
}

#result-area {
  flex: 1;
  min-width: 280px;
}

#result-card {
  background: linear-gradient(135deg, #E3F2FD, #BBDEFB);
  border-radius: 16px;
  padding: 32px 24px;
  text-align: center;
  min-height: 320px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 16px;
}

#result-title {
  font-size: 18px;
  color: #0D47A1;
  margin: 0;
}

#result-value {
  display: flex;
  align-items: baseline;
  gap: 6px;
}

#result-water-ml {
  font-size: 48px;
  font-weight: 700;
  color: #0D47A1;
}

#result-unit {
  font-size: 16px;
  color: #1565C0;
}

#result-cups {
  font-size: 16px;
  color: #37474F;
}

#result-cup-count {
  font-size: 28px;
  font-weight: 700;
  color: #1565C0;
}

#result-tips {
  margin-top: 8px;
}

#tip-text {
  font-size: 14px;
  color: #607D8B;
  margin: 0;
  line-height: 1.6;
}

#__fork {
  text-align: center;
  margin: 40px 0 20px;
}

#__fork button {
  padding: 10px 28px;
  background: #fff;
  border: 1px solid #BBDEFB;
  border-radius: 8px;
  font-size: 14px;
  color: #1565C0;
  cursor: pointer;
  transition: background 0.2s;
}

#__fork button:hover {
  background: #E3F2FD;
}

#features {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 16px 30px;
}

#features h2 {
  font-size: 20px;
  color: #0D47A1;
  margin: 0 0 12px 0;
}

#features p {
  font-size: 15px;
  color: #455A64;
  line-height: 1.8;
  margin: 0;
}

#scenarios {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 16px 30px;
}

#scenarios h2 {
  font-size: 20px;
  color: #0D47A1;
  margin: 0 0 12px 0;
}

#scenarios ul {
  margin: 0;
  padding: 0 0 0 20px;
}

#scenarios li {
  font-size: 15px;
  color: #455A64;
  line-height: 1.8;
}

#FAQ {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 16px 40px;
}

#FAQ h2 {
  font-size: 20px;
  color: #0D47A1;
  margin: 0 0 12px 0;
}

#FAQ dl {
  margin: 0;
}

#FAQ dt {
  font-size: 15px;
  font-weight: 600;
  color: #263238;
  margin: 16px 0 6px 0;
}

#FAQ dd {
  font-size: 14px;
  color: #607D8B;
  line-height: 1.7;
  margin: 0 0 0 0;
}

.page-info {
  text-align: center;
  padding: 20px 16px;
  font-size: 13px;
  color: #90A4AE;
}

.page-info a {
  color: #1565C0;
  text-decoration: none;
}

.page-info a:hover {
  text-decoration: underline;
}

@media (max-width: 768px) {
  #calculator-body {
    flex-direction: column;
  }

  #app-title {
    font-size: 24px;
  }

  #result-water-ml {
    font-size: 40px;
  }

  #result-cup-count {
    font-size: 24px;
  }
}

@media (max-width: 480px) {
  #app {
    padding: 16px 12px 30px;
  }

  #app-title {
    font-size: 22px;
  }

  .input-card {
    padding: 16px;
  }

  #result-card {
    padding: 24px 16px;
    min-height: 260px;
  }

  #result-water-ml {
    font-size: 36px;
  }

  #result-cup-count {
    font-size: 22px;
  }
}