html {
  min-height: 100%;
}

body {
  font-family: Arial, sans-serif;
  min-height: 100vh;
  margin: 0;
  padding: 0;
  color: white;
  text-align: center;
  background-image: url("../assets/images/lp.png");
  background-repeat: no-repeat;
  background-position: center center;
  background-attachment: fixed;
  background-size: cover;
  background-color: #0d1530;
  background-blend-mode: lighten;
  position: relative;
}

body::before {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.22);
  pointer-events: none;
}

.contenedor {
  position: relative;
  z-index: 1;
  max-width: 550px;
  margin: 40px auto;
  background: rgba(0, 0, 0, 0.18);
  padding: 26px;
  border-radius: 24px;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.25);
  backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

input[type="text"], input[type="password"] {
  width: 80%;
  padding: 12px;
  border-radius: 10px;
  border: none;
  font-size: 16px;
  margin-bottom: 20px;
}

button {
  background: #ffcc00;
  color: rgb(68, 42, 42);
  padding: 12px 25px;
  border: none;
  border-radius: 12px;
  font-size: 16px;
  cursor: pointer;
  font-weight: bold;
  margin: 10px;
}

button:hover { background: #ffd633; }

a { text-decoration: none; }

.tarjetas {
  display: flex;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
}

.tarjeta {
  background: rgba(255, 255, 255, 0.78);
  color: black;
  width: 195px;
  padding: 14px;
  border-radius: 18px;
  cursor: pointer;
  transition: transform .2s, box-shadow .2s;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.55);
}
.tarjeta:hover {
  transform: scale(1.04);
  box-shadow: 0 14px 32px rgba(0, 0, 0, 0.18);
}

.avatar-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 5px;
  margin-top: 20px;
}

.avatar-item {
  background: white;
  border-radius: 15px;
  padding: 10px;
  color: black;
  cursor: pointer;
  transition: .2s;
}
.avatar-item:hover { transform: scale(1.03); }
.avatar-item .emoji {
  font-size: 60px;
}

.lista-alumnos {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 15px;
  margin-top: 20px;
}

.alumno-card {
  background: rgba(255,255,255,0.9);
  color: black;
  border-radius: 15px;
  padding: 15px;
}
.alumno-card .emoji { font-size: 42px; }

.opcion {
  background: white;
  color: black;
  margin: 12px 0;
  padding: 15px;
  border-radius: 12px;
  text-align: left;
}