body {
  font-family: 'Segoe UI', sans-serif;
  margin: 0;
  background: #f4f4f4;
  color: #001737;
  padding: 20px;
}

.container {
  max-width: 600px;
  margin: auto;
  background: #fff;
  border-radius: 12px;
  padding: 24px;
  box-shadow: 0 0 15px rgba(0, 0, 0, 0.1);
}

.title {
  text-align: center;
  font-size: 28px;
  margin-bottom: 30px;
}

.gradient {
  background: linear-gradient(to right, #20c997, #138d75, #001f3f);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 700;
}

.course {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 15px;
}

.course input {
  flex: 1 1 30%;
  padding: 10px;
  border: 1px solid #aaa;
  border-radius: 6px;
  background: #ffffff;
}

.buttons,
.export-buttons {
  text-align: center;
  margin: 15px 0;
}

button {
  padding: 10px 20px;
  margin: 5px;
  border: none;
  font-weight: bold;
  cursor: pointer;
  border-radius: 8px;
}

.primary {
  background-color: #20c997;
  color: white;
}

.primary:hover {
  background-color: #138d75;
}

.secondary {
  background-color: #001f3f;
  color: white;
}

.secondary:hover {
  background-color: #001737;
}

.result-box {
  text-align: center;
  padding: 15px;
  background: #e6f9f2;
  border: 1px solid #20c997;
  border-radius: 10px;
  font-size: 20px;
  font-weight: bold;
  margin-top: 15px;
}

.hidden {
  display: none;
}

@media (max-width: 600px) {
  .course input {
    flex: 1 1 100%;
  }
}