:root{
  --green:#007A3D;
  --red:#CE1126;
  --yellow:#FCD116;
  --bg:#f3f4f6;
  --card:#ffffff;
  --text:#222;
}

*{box-sizing:border-box;margin:0;padding:0;font-family:Segoe UI, Arial, sans-serif;}
body{background:var(--bg); color:var(--text);}

header{
  background:linear-gradient(90deg,var(--green),var(--red),var(--yellow));
  color:#fff; padding:18px; text-align:center;
  box-shadow:0 3px 10px rgba(0,0,0,.15);
}

.nav{
  display:flex; justify-content:center; gap:20px; margin-top:8px; flex-wrap:wrap;
}
.nav button{
  background:#fff; color:var(--green); border:none; padding:8px 14px; border-radius:6px;
  cursor:pointer; font-weight:600;
}

.section{display:none; padding:24px 16px;}
.section.active{display:block;}

.container{
  max-width:1000px; margin:0 auto; background:var(--card); padding:24px;
  border-radius:14px; box-shadow:0 6px 18px rgba(0,0,0,.15);
}

h2{color:var(--green); margin-bottom:12px;}
h3{color:var(--red); margin-top:18px;}

.grid{
  display:grid; grid-template-columns:repeat(auto-fit,minmax(240px,1fr)); gap:16px; margin-top:16px;
}

.card{
  background:#fff; border-left:6px solid var(--green);
  padding:16px; border-radius:10px; box-shadow:0 4px 10px rgba(80, 90, 90, 0.12);
  transition:.3s; border-color: #222;
}
.card:hover{transform:translateY(-6px);}

input,select{
  width:100%; padding:10px; margin:8px 0; border-radius:6px; border:1px solid #ccc;
}

button.primary{
  background:var(--green); color:#fff; border:none; padding:12px 18px; border-radius:6px;
  cursor:pointer; font-weight:600; margin-top:10px;
}
button.primary:hover{background:var(--red);}

.bulletin{
  margin-top:20px; animation:fade .6s ease;
}
.student-info{
  background:#36eb09; border:1px solid #ddd; padding:12px; border-radius:8px; margin-bottom:14px; border-color: #CE1126;
}

table{width:100%; border-collapse:collapse; margin-top:12px;}
th{background:var(--green); color:#fff; padding:10px;}
td{padding:8px; border:1px solid #ddd; text-align:center;}

.result{
  margin-top:16px; padding:14px; border-radius:10px; background:var(--yellow);
  font-weight:bold;
}

footer{
  text-align:center; padding:16px; margin-top:30px; font-size:14px; color:#555;
}

@keyframes fade{
  from{opacity:0; transform:translateY(20px);}
  to{opacity:1;}
}

#C1{
  background-color: #36eb09;
}
#C2{
  background-color: #e93e0a;
}#C3{
  background-color: #e8f80b;
}#C4{
  background-color: #0920eb;
}