body.dark-mode {
  background: #111;
  color: white;
}

.gpa-tool-container {
  display: flex;
  justify-content: center;
  padding: 40px;
}

.theme-toggle {
  position: absolute;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  padding: 10px 20px;
  border-radius: 30px;
  border: none;
  cursor: pointer;
  background: #444;
  color: white;
  transition: 0.3s;
}

.gpa-card {
  width: 420px;
  background: white;
  padding: 30px;
  border-radius: 20px;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

body.dark-mode .gpa-card {
  background: #1e1e1e;
  color: white;
}

input, select {
  width: 100%;
  padding: 12px;
  margin-top: 8px;
  border-radius: 10px;
  border: 1px solid #aaa;
}

.calculate-btn {
  width: 100%;
  margin-top: 20px;
  padding: 14px;
  background: #4a39f0;
  color: white;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  font-size: 17px;
  position: relative;
  overflow: hidden;
}

.calculate-btn:active::after {
  content: "";
  position: absolute;
  width: 300%;
  height: 300%;
  background: rgba(255,255,255,0.3);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0);
  border-radius: 50%;
  animation: ripple 0.5s linear;
}

@keyframes ripple {
  to {
    transform: translate(-50%, -50%) scale(1);
    opacity: 0;
  }
}

.result-text {
  margin-top: 20px;
  font-size: 20px;
  font-weight: bold;
}