/* ==============================
   Layout básico
   ============================== */
body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: #0b2b66;
  color: #fff;
  text-align: center;
}

/* ==============================
   Header superior (grid de 4 colunas)
   ============================== */
.top-header {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  padding: 16px;
  background: #0b2b66;
  position: sticky;
  top: 0;
  z-index: 30;
}

/* ==============================
   Estilo base dos botões superiores
   ============================== */
.btn {
  border: 0;
  border-radius: 12px;
  padding: 10px;
  font-weight: bold;
  font-size: 15px;
  color: #fff;
  cursor: pointer;
  text-align: center;
  text-decoration: none;
  box-shadow: 2px 4px 10px rgba(0,0,0,.45);
  transition: transform .1s ease, box-shadow .1s ease;
  text-shadow: 1px 1px 3px rgba(0,0,0,0.9);
}
.btn:hover {
  transform: scale(1.05);
}
.btn:active {
  transform: translateY(1px);
}

/* ==============================
   Cores individuais dos botões
   ============================== */
.btn-links   { background: linear-gradient(135deg,#2aa4ff,#0b5be8); }
.btn-contato { background: linear-gradient(135deg,#ffd24d,#f7a300); }
.btn-sobre   { background: linear-gradient(135deg,#3ed477,#118a3a); }
.btn-avisos  { background: linear-gradient(135deg,#666,#444); color:#ccc; }

/* ==============================
   Extra: fonte e sombra
   ============================== */
.btn-font {
  font-family: Arial, Helvetica, sans-serif;
}
.btn-shadow {
  box-shadow: 0px 3px 8px rgba(0,0,0,0.6);
}

/* ==============================
   Avisos ativos (pulso)
   ============================== */
.btn-avisos.ativo {
  background: linear-gradient(135deg,#ffcc00,#ff9900);
  color: #fff;
  box-shadow: 0 0 15px #ffcc00, 0 0 30px #ff9900;
  animation: pulse 1.5s infinite;
}
@keyframes pulse {
  0% { transform: scale(1); box-shadow: 0 0 12px #ffcc00; }
  50% { transform: scale(1.08); box-shadow: 0 0 20px #ffcc00, 0 0 35px #ff9900; }
  100% { transform: scale(1); box-shadow: 0 0 12px #ffcc00; }
}