body { background:#000; color:f9f9f9; padding:10px; } #algorithm { label { width:250px; display:inline-block; } } .hidden { display:none !important; } .running:before { display:inline-block; content: ' '; border-radius: 50%; border: .5rem solid rgba(0,0,0,0.25); border-top-color: #fff; animation: spin 1s infinite linear; width:16px; height:16px; } @keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } } #drop-area { border: 2px dashed #ccc; border-radius: 20px; max-width:480px; width: 50%; font-family: sans-serif; margin: 10px 0; padding: 20px; &.highlight { border-color: purple; } } .button { display: inline-block; padding: 10px; color:#000; background: #ccc; cursor: pointer; border-radius: 5px; border: 1px solid #ccc; &:hover { background: #ddd; } } #fileElem { display: none; }