*{
margin:0;
padding:0;
box-sizing:border-box;
font-family: "Segoe UI", Arial, sans-serif;
}

body{
background: linear-gradient(135deg,#667eea,#764ba2);
min-height:100vh;
display:flex;
flex-direction:column;
}

/* Header */

header{
text-align:center;
padding:50px 20px;
color:white;
}

header h1{
font-size:40px;
margin-bottom:10px;
letter-spacing:1px;
}

header p{
font-size:18px;
opacity:0.9;
}

/* Container */

.container{
width:90%;
max-width:1100px;
margin:auto;
display:grid;
grid-template-columns:repeat(auto-fit,minmax(200px,1fr));
gap:30px;
padding:40px 0;
}

/* Card tuần */

.week{
background:rgba(255,255,255,0.15);
backdrop-filter:blur(10px);
padding:40px;
text-align:center;
font-size:22px;
font-weight:600;
text-decoration:none;
color:white;
border-radius:15px;
border:1px solid rgba(255,255,255,0.3);
transition:all 0.3s ease;
box-shadow:0 10px 20px rgba(0,0,0,0.2);
}

/* Hover */

.week:hover{
transform:translateY(-10px) scale(1.05);
background:white;
color:#333;
box-shadow:0 15px 30px rgba(0,0,0,0.3);
}

/* Footer */

footer{
margin-top:auto;
text-align:center;
padding:20px;
color:white;
opacity:0.8;
}