body { font-family: system-ui, sans-serif; background: #f9fafb; color: #222; margin:0; padding:0;}
header { background:#1d4ed8; color:white; padding:1rem; text-align:center; }
header nav button { margin:0.5rem; padding:0.5rem 1rem; background:white; color:#1d4ed8; border:none; border-radius:6px; cursor:pointer; font-size:1rem; transition:0.2s; }
header nav button:hover { background:#e0e7ff; }
main { max-width:800px; margin:2rem auto; padding:0 1rem; }
.course-card, .assignment-card, .quiz-card, .announcement-card { background:white; border-radius:10px; padding:1rem; margin:0.75rem 0; box-shadow:0 2px 6px rgba(0,0,0,0.05); transition:transform 0.2s;}
.course-card:hover, .assignment-card:hover, .quiz-card:hover { transform:translateY(-3px);}
.course-card h3, .assignment-card h3, .quiz-card h3 { margin-top:0; }
button.action { background:#1d4ed8; color:white; border:none; padding:0.4rem 0.75rem; border-radius:4px; cursor:pointer; margin-top:0.5rem; }
button.action:hover { background:#2563eb; }
footer { text-align:center; padding:1rem; color:#666; font-size:0.85rem; }
.error { color:red; }
input, textarea { width:100%; padding:0.5rem; margin:0.5rem 0; border-radius:4px; border:1px solid #ccc; font-family:inherit;}