:root{--primary-bg: #ffffff;--secondary-bg: #f5f5f5;--border-color: #e0e0e0;--text-color: #333333;--accent-color: #4a90e2;--toolbar-height: 60px}*{box-sizing:border-box;margin:0;padding:0}body{font-family:Arial,sans-serif;color:var(--text-color);background-color:var(--primary-bg);height:100vh;overflow:hidden}#app{display:flex;flex-direction:column;height:100vh;width:100vw}button{cursor:pointer;border:none;background:none;font-family:inherit}button:focus{outline:none}.toolbar-btn{padding:8px 16px;margin:0 4px;background-color:var(--secondary-bg);border-radius:4px;font-size:14px;transition:background-color .2s}.toolbar-btn:hover{background-color:var(--border-color)}.toolbar-btn:disabled{opacity:.5;cursor:not-allowed}input[type=text]{padding:8px;border:1px solid var(--border-color);border-radius:4px;font-size:14px;width:200px}input[type=text]:focus{outline:none;border-color:var(--accent-color)}.canvas-container{flex:1;position:relative;overflow:hidden;background-color:var(--primary-bg);cursor:crosshair}#drawing-canvas{position:absolute;top:0;left:0;width:100%;height:100%;touch-action:none}.canvas-container:before{content:"";position:absolute;top:0;left:0;right:0;bottom:0;background-image:linear-gradient(to right,rgba(0,0,0,.05) 1px,transparent 1px),linear-gradient(to bottom,rgba(0,0,0,.05) 1px,transparent 1px);background-size:20px 20px;pointer-events:none}.toolbar{display:flex;align-items:center;padding:0 20px;height:var(--toolbar-height);background-color:var(--secondary-bg);border:1px solid var(--border-color)}.top-toolbar{justify-content:space-between;border-bottom:1px solid var(--border-color)}@media (min-width: 1200px){.top-toolbar{padding:0 max(20px,calc((100% - 1200px)/2))}}.bottom-toolbar{justify-content:space-between;border-top:1px solid var(--border-color)}.whiteboard-name{flex:0 0 auto;min-width:200px}.utility-controls{display:flex;align-items:center;margin-left:auto}.color-picker,.tool-picker{display:flex;gap:10px}.color-btn{width:30px;height:30px;border-radius:50%;border:2px solid var(--border-color);transition:transform .2s,border-color .2s}.color-btn:hover{transform:scale(1.1)}.color-btn.active{border-color:var(--accent-color);transform:scale(1.1)}.tool-btn{padding:8px 16px;background-color:var(--secondary-bg);border:1px solid var(--border-color);border-radius:4px;font-size:14px;transition:background-color .2s,transform .2s}.tool-btn:hover{background-color:var(--border-color)}.tool-btn.active{background-color:var(--accent-color);color:#fff;transform:scale(1.05)}.color-btn[data-color=black]{background-color:#000}.color-btn[data-color=white]{background-color:#fff}.color-btn[data-color=red]{background-color:#e74c3c}.color-btn[data-color=green]{background-color:#2ecc71}.color-btn[data-color=blue]{background-color:#3498db}.color-btn[data-color=yellow]{background-color:#f1c40f}.modal-overlay{position:fixed;top:0;left:0;right:0;bottom:0;background-color:#00000080;display:flex;align-items:center;justify-content:center;z-index:1000}.modal-content{background-color:#fff;border-radius:8px;width:80%;max-width:800px;max-height:80vh;overflow:hidden;display:flex;flex-direction:column;box-shadow:0 4px 12px #00000026}.modal-header{display:flex;justify-content:space-between;align-items:center;padding:16px 20px;border-bottom:1px solid var(--border-color)}.modal-header h2{margin:0;font-size:20px;color:var(--text-color)}.close-btn{background:none;border:none;font-size:24px;cursor:pointer;color:var(--text-color);opacity:.7;transition:opacity .2s}.close-btn:hover{opacity:1}.action-bar{display:flex;justify-content:space-between;align-items:center;padding:12px 20px;border-bottom:1px solid var(--border-color);background-color:var(--secondary-bg)}.search-container{flex:1;max-width:400px}#search-input{width:100%;padding:8px 12px;border:1px solid var(--border-color);border-radius:4px;font-size:14px}.button-container{display:flex;gap:8px}.modal-body{flex:1;overflow-y:auto;padding:0}.file-list{width:100%;border-collapse:collapse}.file-list th,.file-list td{padding:12px 20px;text-align:left;border-bottom:1px solid var(--border-color)}.file-list th{background-color:var(--secondary-bg);font-weight:600;color:var(--text-color)}.file-list tr:hover{background-color:#00000005}.file-name{font-weight:500}.file-date{color:#666;white-space:nowrap}.file-actions{white-space:nowrap;text-align:right}.action-btn{padding:6px 12px;background-color:var(--secondary-bg);border:1px solid var(--border-color);border-radius:4px;font-size:14px;cursor:pointer;transition:background-color .2s}.action-btn:hover{background-color:var(--border-color)}.open-btn{background-color:var(--accent-color);color:#fff;border-color:var(--accent-color)}.open-btn:hover{background-color:#3a80d1;border-color:#3a80d1}.action-menu-btn{padding:6px 10px;margin-left:8px;background-color:var(--secondary-bg);border:1px solid var(--border-color);border-radius:4px;font-size:14px;cursor:pointer;transition:background-color .2s}.action-menu-btn:hover{background-color:var(--border-color)}.action-menu{position:absolute;right:20px;background-color:#fff;border:1px solid var(--border-color);border-radius:4px;box-shadow:0 2px 8px #0000001a;z-index:10;display:none}.action-menu-item{display:block;width:100%;text-align:left;padding:8px 16px;background:none;border:none;cursor:pointer;font-size:14px;transition:background-color .2s}.action-menu-item:hover{background-color:var(--secondary-bg)}.delete-item{color:#e74c3c}.delete-item:hover{background-color:#fee}.empty-state{padding:40px 20px;text-align:center;color:#666;font-style:italic}.toast-container{position:fixed;bottom:20px;right:20px;z-index:1000;display:flex;flex-direction:column;gap:10px}.toast{background-color:var(--accent-color);color:#fff;padding:12px 20px;border-radius:4px;box-shadow:0 2px 10px #0000001a;display:flex;align-items:center;justify-content:space-between;min-width:250px;max-width:350px;animation:toast-in .3s ease-out forwards;opacity:0;transform:translateY(20px)}.toast.success{background-color:#2ecc71}.toast.error{background-color:#e74c3c}.toast.info{background-color:var(--accent-color)}.toast-message{flex:1;margin-right:10px}.toast-close{background:none;border:none;color:#fff;font-size:16px;cursor:pointer;opacity:.7;transition:opacity .2s}.toast-close:hover{opacity:1}@keyframes toast-in{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}@keyframes toast-out{0%{opacity:1;transform:translateY(0)}to{opacity:0;transform:translateY(-20px)}}.toast.removing{animation:toast-out .3s ease-in forwards}