/* ================= Body Style ================= */
body {
  font-family: 'Segoe UI', sans-serif;
  margin: 0;
  padding: 0;
  background: #0d1b2a;
}

/* ================= Header Section ================= */
.main-header {
  height: 60px;
  background: linear-gradient(135deg, #003366, #005580);
  display: flex;                  
  justify-content: space-between; 
  align-items: center;            
  padding: 0px 30px;
  color: white;
  position: sticky;              
  top: 0;
  z-index: 1000;                  
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  backdrop-filter: blur(6px);    
}

.logo-title {
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo-title h1 {
  font-size: 1.8rem;
  font-weight: bold;
  letter-spacing: 1px;
  padding-bottom: 5px;
}

.logo-title h1 span {
  color: #00bcd4;
}

.nav-links a {
  margin-left: 25px;
  text-decoration: none;
  color: white;
  font-weight: 500;
  transition: color 0.3s, border-bottom 0.3s;
  position: relative;
}

/*=== Underline effect on hover ===*/
.nav-links a::after {
  content: "";
  display: block;
  height: 2px;
  width: 0%;
  background: #00bcd4;
  position: absolute;
  bottom: -5px;
  left: 0;
  transition: 0.3s;
}

.nav-links a:hover {
  color: #00bcd4;
}

.nav-links a:hover::after {
  width: 100%;
}

/* ================= RESPONSIVE HEADER ================= */
@media (max-width: 768px) {
  .main-header {
    flex-direction: column;   
    align-items: flex-start;  
  }

  .nav-links {
    display: flex;
    flex-wrap: wrap;          
  }

  .nav-links a {
    margin: 10px 15px 0 0;   
  }
}

/* ================= QUESTION SECTION ================= */
label {
  display: block;
  margin: 8px 0;
  padding: 5px;
  border-radius: 5px;
  background: #e0f0ff;
  transition: background 0.3s;
}

label:hover {
  background: #315e8f;
  cursor: pointer;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.question {
  max-width: 700px;           
  width: 90%;                 
  display: none;             
  background: #1b263b;
  padding: 20px;
  border-radius: 8px;
  margin: 20px auto;          
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.question.active {
  display: block;
}

/* Responsive question adjustments */
@media (max-width: 600px) {
  .question {
    width: 95%;               
    padding: 15px;           
  }

  legend {
    font-size: 20px;         
  }
}

legend {
  font-size: 25px;
  font-weight: bold;
  color: #00bcd4;
}

.feedback {
  margin-top: 10px;
  font-weight: bold;
  color: #fff;
}

.correct {
  color: green;
}

.incorrect {
  color: red;
}

.nav-buttons {
  margin-top: 10px;
  display: flex;
  flex-wrap: wrap;           
}

.nav-buttons button {
  margin: 5px 10px 0 0;
  padding: 5px 10px;
  background-color: #005580;
  border: none;
  color: white;
  border-radius: 5px;
}

.nav-buttons button:hover {
  background-color: #002244;
  cursor: pointer;
}

/* ================= FOOTER SECTION ================= */
.footer {
  background-color: #002244;
  color: white;
  padding: 20px 20px 10px;
  margin-top: 20px;
}

.footer-flex {
  display: flex;
  justify-content: space-around;
  flex-wrap: wrap;           
  text-align: left;
  margin-bottom: 20px;
  gap: 20px;
}

.footer-block {
  max-width: 255px;
}

.footer-contact-heading,
.footer-mathverse-heading,
.footer-nav-heading {
  color: #00bcd4;
}

.footer-block a {
  display: block;
  color: white;
  text-decoration: none;
  margin: 5px 0;
}

.footer-block a:hover {
  color: #00bcd4;
}

.footer-bottom {
  text-align: center;
  font-size: 0.9rem;
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  padding-top: 10px;
}

/* ================= RESPONSIVE FOOTER ================= */
@media (max-width: 768px) {
  .footer-flex {
    flex-direction: column;   
    align-items: center;
    text-align: center;
  }

  .footer-block {
    max-width: 100%;         
  }
}