body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  padding: 20px;
  background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
  min-height: 100vh;
  margin: 0;
  color: #334155;
  line-height: 1.6;
}

h1 {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  text-align: center;
  font-size: 2.5rem;
  font-weight: 700;
  color: #1e293b;
  margin-bottom: 2rem;
  letter-spacing: -0.025em;
}

.disclaimer {
  font-weight: 600;
  font-style: italic;
  color: #64748b;
}

#bra-calculator {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  padding: 2.5rem;
  max-width: 650px;
  margin: 3rem auto 2rem;
  text-align: center;
  border-radius: 20px;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 
              0 10px 10px -5px rgba(0, 0, 0, 0.04);
  border: 1px solid rgba(226, 232, 240, 0.5);
}

.title {
  font-size: 1.75rem;
  font-weight: 600;
  margin-bottom: 2rem;
  color: #1e293b;
  letter-spacing: -0.025em;
}

.half {
  width: calc(50% - 2rem);
  float: left;
  padding: 0 1rem;
  margin-bottom: 1.5rem;
}

label {
  font-size: 1rem;
  font-weight: 500;
  display: block;
  margin: 1rem auto 0.5rem;
  color: #475569;
  text-align: left;
}

.error-message {
  font-size: 0.875rem;
  margin: 0.75rem auto;
  text-align: left;
  font-weight: 500;
  color: #dc2626;
  display: none;
  background: rgba(254, 226, 226, 0.8);
  padding: 0.5rem 0.75rem;
  border-radius: 8px;
  border-left: 4px solid #dc2626;
}

.error-message.show {
  display: block;
  animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

input[type=number] {
  border: 2px solid #e2e8f0;
  border-radius: 12px;
  font-size: 1.125rem;
  padding: 0.875rem 1rem;
  outline: none;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  width: 100%;
  background: #ffffff;
  transition: all 0.2s ease;
  box-sizing: border-box;
}

input[type=number]:focus {
  border-color: #3b82f6;
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

input[type=number]:hover {
  border-color: #cbd5e1;
}

input[type=number].error {
  border-color: #dc2626;
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.1);
}

input[type=submit] {
  background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
  color: white;
  border: none;
  border-radius: 12px;
  padding: 1.25rem 2rem;
  font-size: 1.25rem;
  font-weight: 600;
  margin-top: 2rem;
  cursor: pointer;
  letter-spacing: 0.025em;
  outline: none;
  width: 100%;
  transition: all 0.2s ease;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 
              0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

input[type=submit]:hover {
  background: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
  transform: translateY(-2px);
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 
              0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

input[type=submit]:active {
  transform: translateY(0);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 
              0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

#bra-results {
  font-size: 1.875rem;
  margin-top: 2rem;
  padding: 1.5rem;
  border-radius: 12px;
  background: linear-gradient(135deg, #ecfdf5 0%, #d1fae5 100%);
  border: 1px solid #a7f3d0;
  animation: fadeIn 0.5s ease-out;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: scale(0.95);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

#bra-results.show {
  display: block;
}

#bra-results span {
  font-weight: 700;
  color: #065f46;
  font-size: 2.25rem;
  display: block;
  margin-top: 0.5rem;
}

/* Article Styles */
#article {
  padding: 4rem 10% 2rem;
  max-width: 900px;
  margin: 0 auto;
  background: rgba(255, 255, 255, 0.7);
  border-radius: 20px;
  margin-top: 4rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

#article h2 {
  color: #1e293b;
  font-weight: 600;
  font-size: 1.5rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
}

#article p, #article li {
  color: #475569;
  font-size: 1rem;
  line-height: 1.7;
}

#article ul, #article ol {
  margin: 1rem 0;
  padding-left: 1.5rem;
}

#article hr {
  border: none;
  height: 1px;
  background: linear-gradient(90deg, transparent, #e2e8f0, transparent);
  margin: 2rem 0;
}

@media screen and (max-width: 767px) {
  body {
    padding: 1rem;
  }

  h1 {
    font-size: 2rem;
  }

  #bra-calculator {
    padding: 2rem 1.5rem;
    margin: 2rem auto 1rem;
  }

  .title {
    font-size: 1.5rem;
  }

  .half {
    float: none;
    width: 100%;
    padding: 0;
    margin-bottom: 1.5rem;
  }

  input[type=number] {
    width: 100%;
  }

  input[type=submit] {
    font-size: 1.125rem;
    padding: 1rem 1.5rem;
  }

  #bra-results {
    font-size: 1.5rem;
  }

  #bra-results span {
    font-size: 1.875rem;
  }

  #article {
    padding: 2rem 5%;
    margin-top: 2rem;
  }
}

@media screen and (max-width: 480px) {
  #article {
    padding: 1.5rem;
  }
}