.btn {
  font-family: "Nunito", "Inter", sans-serif;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  border: none;
  border-radius: 6px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s ease;
  text-decoration: none;
  letter-spacing: 0.025em;
  position: relative;
  overflow: hidden;
}
.btn::before {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.2),
    transparent
  );
  transition: left 0.5s ease;
}

.btn:hover::before {
  left: 100%;
}

.btn-primary {
  background-color: #3498db;
  color: white;
}

.btn-primary:hover {
  background-color: #2980b9;
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
}

.btn-secondary {
  background: transparent;
  color: #009fc9;
  border: 2px solid #009fc9;
}

.btn-secondary:hover {
  background: #009fc9;
  color: white;
  transform: translateY(-2px);
}

.btn-white {
  background: white;
  color: #009fc9;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.btn-white:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.15);
}

.btn-outline {
  background: transparent;
  color: #009fc9;
  border: 2px solid #009fc9;
}

.btn-outline:hover {
  background: #009fc9;
  color: white;
  transform: translateY(-2px);
}

.btn-success {
  background-color: #27ae60;
  color: white;
}

.btn-success:hover {
  background-color: #219a52;
}

.course-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px; /* ← GIẢM TỪ 12px 24px XUỐNG 10px 20px */
  background: linear-gradient(135deg, #009fc9, #3498db);
  color: white;
  text-decoration: none;
  border-radius: 12px;
  font-weight: 600;
  font-size: 13px; /* ← GIẢM TỪ 14px XUỐNG 13px */
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
  white-space: nowrap;
}

.course-btn::before {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.2),
    transparent
  );
  transition: left 0.5s ease;
}

.course-btn:hover::before {
  left: 100%;
}

.course-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0, 159, 201, 0.4);
}

.course-btn i {
  transition: transform 0.3s ease;
}

.course-btn:hover i {
  transform: translateX(4px);
}