* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Arial", sans-serif;
}

body {
  line-height: 1.6;
  color: #333;
}

.homepage {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.gradepage,
.percentagepage {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background-color: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

nav ul {
  display: flex;
  justify-content: center;
  align-items: center;
  list-style: none;
  padding: 1rem;
  gap: 2rem;
}

nav a {
  text-decoration: none;
  color: #333;
  padding: 0.5rem 1rem;
  border-radius: 25px;
  transition: all 0.3s ease;
  font-weight: 500;
}

nav a:hover {
  background-color: #667eea;
  color: white;
  transform: translateY(-2px);
}

.h1 {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  flex: 1;
  text-align: center;
  padding: 2rem;
  color: white;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.h1 h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  font-weight: 700;
}

.percentage-form {
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-radius: 20px;
  padding: 3rem;
  margin: 2rem auto;
  max-width: 500px;
  width: 90%;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

input {
  padding: 1rem;
  border: 2px solid #ddd;
  border-radius: 10px;
  font-size: 1rem;
  transition: border-color 0.3s ease;
  text-align: center;
}

input:focus {
  outline: none;
  border-color: #667eea;
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

input::placeholder {
  color: #999;
  font-style: italic;
}

#btn {
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: white;
  border: none;
  padding: 1rem 2rem;
  border-radius: 25px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 600;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

#btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

#btn:active {
  transform: scale(0.98);
}

.output {
  display: none;
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: white;
  padding: 1rem;
  border-radius: 10px;
  text-align: center;
  font-weight: 600;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

/* Mobile responsiveness */
@media (max-width: 768px) {
  nav ul {
    flex-direction: column;
    gap: 1rem;
  }

  .h1 h1 {
    font-size: 2rem;
  }

  .percentage-form {
    margin: 1rem auto;
    padding: 2rem;
  }

  input {
    padding: 0.8rem;
  }

  #btn {
    padding: 0.8rem 1.5rem;
  }
}

@media (max-width: 480px) {
  .h1 h1 {
    font-size: 1.5rem;
  }

  .percentage-form {
    padding: 1.5rem;
  }
}