body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  color: #333;
  min-height: 100vh;
  position: relative;
  display: flex;
  flex-direction: column;
}

main.container {
  flex: 1 0 auto;
}

footer {
  flex-shrink: 0;
  background: transparent !important;
  /* Loại bỏ màu nền trắng, giữ trong suốt */
}

body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('../img/background.png') no-repeat center center fixed;
  background-size: cover;
  z-index: -2;
}

body:not(.login)::after {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(255, 255, 255, 0.8);
  z-index: -1;
}

body.login .greeting,
body.login .dropdown {
  display: none !important;
}


.greeting {
  text-align: right;
  font-weight: bold;
  font-size: 1.1rem;
  margin-bottom: 15px;
}

.session-card {
  background-color: rgba(255, 255, 255, 0.85);
  border: none;
  margin-bottom: 20px;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.session-header {
  background-color: rgba(247, 211, 210, 0.9);
  color: rgb(237, 98, 98);
  padding: 10px 15px;
  font-weight: 600;
  border-top-left-radius: 8px;
  border-top-right-radius: 8px;
  cursor: pointer;
}

.quiz-item {
  padding: 10px 15px;
  border-top: 1px solid #eee;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: #fffaf9;
  transition: background-color 0.2s ease-in-out;
}

.quiz-item:hover {
  background-color: #e2c2c2;
  cursor: pointer;
}

.quiz-star {
  color: #f6a4a1;
  font-size: 1.2rem;
}

.card.login-card {
  background-color: rgba(255, 255, 255, 0.85);
  border: none;
}

.login-card .card-header {
  background-color: rgba(246, 164, 161, 0.85);
  color: white;
}

.btn-custom-pink {
  background-color: rgba(246, 164, 161, 0.95);
  border: none;
  color: white;
}

.btn-custom-pink:hover {
  background-color: rgba(246, 130, 127, 0.95);
}