@import url("https://fonts.googleapis.com/css2?family=Noto+Sans+KR:wght@300;400;500;700&display=swap");

:root {
  --primary-color: #4db6ac;
  --bg-color: #f0f2f5;
  --text-main: #333;
  --text-sub: #666;
  --card-bg: #ffffff;
  --shadow: 0 10px 30px rgba(0,0,0,0.05);
  --border-radius: 24px;
  --font-family: "Noto Sans KR", sans-serif;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-color);
  color: var(--text-main);
  margin: 0;
  padding: 0;
  line-height: 1.6;
}

nav {
  background: white;
  padding: 1rem 2rem;
  box-shadow: 0 2px 10px rgba(0,0,0,0.05);
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

nav .logo {
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--primary-color);
  text-decoration: none;
}

nav .nav-links a {
  margin-left: 1.5rem;
  text-decoration: none;
  color: var(--text-sub);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

nav .nav-links a:hover { color: var(--primary-color); }

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem;
}

header { text-align: center; padding: 3rem 0; }
header h1 { font-size: 2.2rem; color: var(--primary-color); margin-bottom: 1rem; font-weight: 700; }
header p { color: var(--text-sub); }

.card {
  background: var(--card-bg);
  padding: 2.5rem;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  margin-bottom: 2rem;
}

.form-group { margin-bottom: 1.5rem; text-align: left; }
.form-group label { display: block; font-weight: 700; margin-bottom: 0.5rem; color: var(--text-main); }

.gender-selector { display: flex; gap: 1rem; }
.gender-selector input[type="radio"] { display: none; }
.gender-selector label {
  flex: 1;
  padding: 0.8rem;
  background: #f8f9fa;
  border: 1px solid #eee;
  border-radius: 12px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s;
  font-weight: 500;
}

.gender-selector input[type="radio"]:checked + label {
  background: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
}

input[type="date"], input[type="number"] {
  width: 100%;
  padding: 1rem;
  border: 1px solid #eee;
  border-radius: 12px;
  font-family: inherit;
  font-size: 1rem;
  box-sizing: border-box;
}

.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }

#calculate-btn {
  width: 100%;
  padding: 1.2rem;
  background: var(--primary-color);
  color: white;
  border: none;
  border-radius: 50px;
  font-size: 1.2rem;
  font-weight: 700;
  cursor: pointer;
  margin-top: 1rem;
  transition: all 0.3s;
}

#calculate-btn:hover { background: #3d968e; transform: translateY(-3px); box-shadow: 0 10px 20px rgba(77, 182, 172, 0.2); }

.result-display {
  background: white;
  padding: 2.5rem;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  margin-bottom: 2rem;
  animation: fadeIn 0.4s ease-out;
}

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

.result-header { margin-bottom: 2rem; border-bottom: 1px solid #f0f0f0; padding-bottom: 1rem; }
.result-header h2 { color: var(--primary-color); margin-bottom: 0.5rem; }

.percentile-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 2rem; }
.percentile-item { text-align: center; padding: 1.5rem; background: #f8f9fa; border-radius: 20px; }
.percentile-label { font-size: 0.9rem; color: var(--text-sub); margin-bottom: 0.5rem; }
.percentile-value { font-size: 1.8rem; font-weight: 700; color: var(--text-main); }
.percentile-rank { font-size: 0.9rem; margin-top: 0.5rem; font-weight: 500; }

.rank-normal { color: #388e3c; }
.rank-caution { color: #f57c00; }
.rank-danger { color: #d32f2f; }

.home-link { display: block; text-align: center; margin-top: 3rem; color: var(--text-sub); text-decoration: none; font-size: 0.95rem; }
.home-link:hover { color: var(--primary-color); }

footer { text-align: center; padding: 4rem 2rem; color: var(--text-sub); font-size: 0.85rem; }

@media (max-width: 600px) {
  .form-row, .percentile-grid { grid-template-columns: 1fr; }
}