body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: #f9f9f9;
  color: #333;
}

header {
  background: #0074D9;
  color: white;
  padding: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.site-title {
  font-size: 1.2rem;
}

.nav-bar {
  background: #0074D9;
  display: none;
  justify-content: space-around;
  align-items: center;
}

.nav-link {
  background: #0074D9;
  padding: 0.75rem 1rem;
  display: flex;
  white-space: nowrap;
  color: white;
  text-decoration: none;
  max-width: 100%;
  overflow: hidden;
  justify-content: center;
  align-items: center;
  flex: 1;
  text-align: center;
}

.hamburger {
  font-size: 1.5rem;
  cursor: pointer;
}

.form-area {
  max-width: 400px;
  margin: 2rem auto;
  padding: 2rem;
  background: #fff;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
  border-radius: 8px;
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

.form-area label {
  font-weight: bold;
  margin-bottom: 0.3rem;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.form-area label input[type="checkbox"] {
  /* width: auto; */
  margin-right: 0.5em;
  accent-color: #0074D9;
  vertical-align: middle;
  display: inline-block;
}

.form-area button {
  margin-top: 1rem;
}

input[type="number"], input[type="text"], input[type="email"], input[type="password"], input[type="search"], input[type="tel"], input[type="url"], input[type="date"], input[type="time"], input[type="datetime-local"], input[type="month"], input[type="week"], select {
  padding: 0.6rem 1rem;
  font-size: 1rem;
  border: 1px solid #ccc;
  border-radius: 8px;
  width: 100%;
  box-sizing: border-box;
  background-color: #fff;
  margin-top: 0.2rem;
}

input[type="checkbox"]{
  accent-color: #0074D9;
  width: 1.1em;
  height: 1.1em;
  margin-right: 0.5em;
  vertical-align: middle;
}

button, #calcBtn {
  background-color: #0074D9;
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  border-radius: 8px;
  cursor: pointer;
  margin-top: 1rem;
  transition: background-color 0.2s ease;
}
button:hover, #calcBtn:hover {
  background-color: #005fa3;
}

#resultBoxEGFR {
  margin: 2rem auto 1rem auto;
  /* text-align: center; */
  font-size: 1.2rem;
  font-weight: bold;
  color: #0074D9;
}
#resultBoxCCR {
  margin: 2rem auto 1rem auto;
  /* text-align: center; */
  font-size: 1.2rem;
  font-weight: bold;
  color: #0074D9;
}

footer {
  text-align: center;
  padding: 1rem;
  font-size: 0.9rem;
  background: #eee;
  color: #555;
}

.section.description, section.description {
  max-width: 600px;
  margin: 2.5rem auto 1.5rem auto;
  padding: 1.5rem 2rem;
  background: #eaf6ff;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  text-align: center;
}

.section.description p, section.description p {
  margin: 0.7em 0;
  font-size: 1.08em;
}

.section.description .caution, section.description .caution {
  color: #d9534f;
  font-weight: bold;
  margin-top: 1.2em;
}

.nav-bar.open {
    display: flex;
    flex-direction: column;
    background: #0074D9;
    position: absolute;
    top: 60px;
    left: 0;
    width: 200px;
    z-index: 1000;
}

@media (min-width: 768px) {
  .nav-bar {
    display: flex !important;
    position: static;
    background: none;
  }
  .hamburger {
    display: none;
  }
  .nav-link {
    padding: 0.75rem 1rem;
    display: block;
    white-space: nowrap;
    color: white;
    text-decoration: none;
  }
}

@media (max-width: 768px) {
  .form-area {
    margin: 1rem auto;
    padding: 1rem;
    max-width: 95vw;
    min-width: 0;
    box-sizing: border-box;
  }
} 
.explanation-link {
  display: inline-block;
  margin: 2rem auto 1rem auto;
  background: #fff;
  color: #0074D9;
  border: 2px solid #0074D9;
  border-radius: 5px;
  padding: 0.75rem 2rem;
  text-decoration: none;
  font-weight: bold;
  transition: background 0.2s, color 0.2s;
  text-align: center;
}
.explanation-link:hover {
  background: #0074D9;
  color: #fff;}