* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #0f172a;
  color: white;
  font-family:
    Pretendard,
    -apple-system,
    BlinkMacSystemFont,
    sans-serif;
}

.container {
  width: 100%;
  max-width: 520px;
  margin: 0 auto;
  padding: 20px;
}

.header {
  margin-bottom: 24px;
}

.header h1 {
  margin: 0;
  font-size: 32px;
}

.header p {
  color: #94a3b8;
  margin-top: 8px;
}

.card {
  background: #1e293b;
  border-radius: 24px;
  padding: 20px;
  box-shadow:
    0 10px 30px rgba(0,0,0,0.3);
}

label {
  display: block;
  margin-bottom: 8px;
  margin-top: 18px;
  font-size: 14px;
  color: #cbd5e1;
}

input,
select {
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: 14px;
  background: #334155;
  color: white;
  font-size: 16px;
}

input::placeholder {
  color: #94a3b8;
}

.row {
  display: flex;
  gap: 10px;
}

.row button {
  width: 110px;
}

.grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

button {
  border: none;
  border-radius: 14px;
  padding: 14px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: 0.2s;
}

button:hover {
  opacity: 0.9;
}

.primary {
  width: 100%;
  margin-top: 24px;
  background: #3b82f6;
  color: white;
}

.row button {
  background: #475569;
  color: white;
}

#result {
  margin-top: 24px;
}

.timetable {
  background: #1e293b;
  border-radius: 24px;
  padding: 20px;
}

.period-card {
  display: flex;
  justify-content: space-between;
  align-items: center;

  background: #334155;

  border-radius: 16px;

  padding: 16px;

  margin-bottom: 12px;
}

.period {
  width: 60px;
  height: 60px;

  border-radius: 18px;

  background: #3b82f6;

  display: flex;
  align-items: center;
  justify-content: center;

  font-size: 22px;
  font-weight: bold;
}

.subject {
  flex: 1;
  margin-left: 16px;
  font-size: 18px;
  font-weight: 600;
}

.empty {
  text-align: center;
  color: #94a3b8;
  padding: 40px 0;
}

@media (max-width: 600px) {

  .container {
    padding: 14px;
  }

  .header h1 {
    font-size: 28px;
  }

  .card,
  .timetable {
    border-radius: 20px;
  }

}