:root{
  --bg:#f6f7fb;
  --card:#ffffff;
  --accent:#2b6cb0;
  --muted:#666;
}
*{box-sizing:border-box}
body{font-family:Segoe UI, Roboto, Arial, sans-serif;background:var(--bg);color:#222;margin:0}
.container{max-width:980px;margin:0 auto;padding:20px}
.site-header{background:var(--card);box-shadow:0 1px 4px rgba(0,0,0,.06);}
.site-header .container{display:flex;align-items:center;justify-content:space-between}
.site-header h1{font-size:20px;margin:12px 0}
.site-header nav a{margin-left:12px;color:var(--accent);text-decoration:none}
h2,h3,h4,h5{color:#123}
#filters{margin-top:18px}
.filters button{margin:4px;border:1px solid #ddd;padding:8px 12px;background:#fff;border-radius:6px;cursor:pointer}
.filters button.active{background:var(--accent);color:white;border-color:var(--accent)}
.subject{background:var(--card);padding:14px;margin:12px 0;border-radius:8px;box-shadow:0 1px 3px rgba(0,0,0,.04)}
.subject h4{margin:0 0 8px}
.details{margin-top:8px;color:var(--muted)}
.week-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:10px;margin:14px 0}
.day{
    background:var(--card);
    padding:14px;
    border-radius:8px;
    text-align:center;
    cursor:pointer;
    border:2px solid #e6e6e6;
    transition: all 0.2s ease;
    user-select: none;
    font-weight: 500;
    position: relative;
    overflow: hidden;
}
.day:hover{
    box-shadow:0 4px 12px rgba(0,0,0,.1);
    border-color: var(--accent);
    transform: translateY(-2px);
}
.day:active {
    transform: translateY(1px);
}
.day.active{
    background:var(--accent);
    color:white;
    border-color:var(--accent);
    box-shadow:0 4px 12px rgba(43,108,176,.2);
}
.day-details{background:var(--card);padding:20px;border-radius:8px;margin-top:12px}
.day-details h4{margin:16px 0 8px}
.day-details ul{margin:0;padding-left:20px}
.day-details li{margin:4px 0}
.day-details p{color:var(--muted);font-style:italic;margin:8px 0}
@media(max-width:640px){.week-grid{grid-template-columns:repeat(2,1fr)}.site-header .container{flex-direction:column;align-items:flex-start}}

/* Footer and contact */
footer{margin-top:30px;padding:18px 0;text-align:center;color:var(--muted)}

/* Accessibility helper */
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}

/* small util spacing */
.mt-8{margin-top:8px}
.mb-8{margin-bottom:8px}