@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap');

* {
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
}

body {
  margin: 0;
  min-height: 100vh;
  background: linear-gradient(135deg, #fdfbfb, #ebedee);
  display: flex;
  justify-content: center;
  align-items: center;
  transition: background 0.3s;
}

body.dark {
  background: linear-gradient(135deg, #1e1e2f, #121212);
}

.app {
  background: white;
  width: 100%;
  max-width: 520px;
  padding: 30px;
  border-radius: 20px;
  box-shadow: 0 20px 40px rgba(0,0,0,0.1);
  transition: background 0.3s, color 0.3s;
}

body.dark .app {
  background: #1f1f2e;
  color: #eee;
}

.top {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.subtitle {
  text-align: center;
  color: #777;
  margin-bottom: 25px;
}

body.dark .subtitle {
  color: #aaa;
}

.section {
  margin-bottom: 18px;
}

label {
  font-size: 14px;
  display: block;
  margin-bottom: 6px;
}

input, select {
  width: 100%;
  padding: 10px;
  border-radius: 10px;
  border: 1px solid #ddd;
}

body.dark input,
body.dark select {
  background: #2a2a3d;
  border-color: #444;
  color: #eee;
}

.subject-row {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 10px;
  margin-bottom: 10px;
}

.buttons {
  display: flex;
  gap: 10px;
  margin-top: 20px;
}

button {
  flex: 1;
  padding: 12px;
  border-radius: 12px;
  border: none;
  cursor: pointer;
  background: #f0f0f0;
}

button.primary {
  background: #7b9acc;
  color: white;
}

#themeToggle {
  background: none;
  font-size: 18px;
}

#result {
  margin-top: 25px;
  text-align: center;
  font-weight: 600;
}