:root{--primary-color: #1a73e8;--secondary-color: #34a853;--danger-color: #ea4335;--warning-color: #fbbc04;--background: #f5f5f5;--surface: #ffffff;--text-primary: #202124;--text-secondary: #5f6368;--border-color: #dadce0;--shadow: 0 1px 3px rgba(0, 0, 0, .12), 0 1px 2px rgba(0, 0, 0, .24)}*{margin:0;padding:0;box-sizing:border-box}body{font-family:Google Sans,Roboto,Arial,sans-serif;background-color:var(--background);color:var(--text-primary);line-height:1.6}.container{max-width:1200px;margin:0 auto;padding:0 20px}.header{background:var(--surface);box-shadow:var(--shadow);padding:20px 0;margin-bottom:30px}.header .container{display:flex;justify-content:space-between;align-items:center}.header h1{color:var(--primary-color);font-size:24px}#auth-section{display:flex;align-items:center;gap:15px}.user-info{display:flex;align-items:center;gap:10px}.avatar{width:36px;height:36px;border-radius:50%}.btn{padding:10px 20px;border:none;border-radius:4px;font-size:14px;font-weight:500;cursor:pointer;transition:all .2s}.btn-primary{background-color:var(--primary-color);color:#fff}.btn-primary:hover{background-color:#1557b0}.btn-secondary{background-color:transparent;color:var(--primary-color);border:1px solid var(--primary-color)}.btn-secondary:hover{background-color:#1a73e81a}.btn-large{padding:15px 30px;font-size:16px}.btn:disabled{opacity:.5;cursor:not-allowed}.hidden{display:none!important}.loading{text-align:center;padding:40px}.spinner{border:4px solid var(--border-color);border-top:4px solid var(--primary-color);border-radius:50%;width:40px;height:40px;animation:spin 1s linear infinite;margin:0 auto 20px}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.message-box{background:var(--surface);padding:40px;border-radius:8px;box-shadow:var(--shadow);max-width:600px;margin:40px auto}.message-box h2{color:var(--primary-color);margin-bottom:20px}.message-box ul{margin:20px 0;padding-left:20px}.message-box li{margin:10px 0}.tabs{display:flex;gap:5px;border-bottom:2px solid var(--border-color);margin-bottom:30px;overflow-x:auto}.tab-btn{padding:12px 24px;background:none;border:none;border-bottom:3px solid transparent;color:var(--text-secondary);font-weight:500;cursor:pointer;transition:all .2s;white-space:nowrap}.tab-btn:hover{background-color:#1a73e80d}.tab-btn.active{color:var(--primary-color);border-bottom-color:var(--primary-color)}.tab-pane{display:none}.tab-pane.active{display:block}.stats-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:20px;margin-bottom:30px}.stat-card{background:var(--surface);padding:24px;border-radius:8px;box-shadow:var(--shadow)}.stat-card h3{font-size:14px;color:var(--text-secondary);margin-bottom:10px}.stat-number{font-size:36px;font-weight:700;color:var(--primary-color)}.recent-activity{background:var(--surface);padding:24px;border-radius:8px;box-shadow:var(--shadow)}.recent-activity h3{margin-bottom:20px}.action-bar{display:flex;gap:10px;margin-bottom:20px}.card{background:var(--surface);padding:20px;border-radius:8px;box-shadow:var(--shadow);margin-bottom:15px}.card h3{color:var(--primary-color);margin-bottom:10px}.card p{color:var(--text-secondary);margin:5px 0}.grading-panel{background:var(--surface);padding:30px;border-radius:8px;box-shadow:var(--shadow);margin-bottom:30px}.select-container{margin-bottom:20px}.select-container label{display:block;margin-bottom:8px;font-weight:500;color:var(--text-primary)}.select-input,.text-input{width:100%;padding:12px;border:1px solid var(--border-color);border-radius:4px;font-size:14px}.select-input:disabled{background-color:var(--background);cursor:not-allowed}.ai-options{margin:30px 0;padding:20px;background-color:var(--background);border-radius:4px}.ai-options h3{margin-bottom:15px}.checkbox-label{display:flex;align-items:center;gap:10px;margin:10px 0;cursor:pointer}.checkbox-label input[type=checkbox]{width:18px;height:18px;cursor:pointer}.grading-progress{background:var(--surface);padding:30px;border-radius:8px;box-shadow:var(--shadow)}.grading-progress h3{margin-bottom:20px}.progress-bar{width:100%;height:24px;background-color:var(--background);border-radius:12px;overflow:hidden;margin-bottom:15px}.progress-fill{height:100%;background-color:var(--secondary-color);transition:width .3s ease;width:0%}#grading-status{margin-bottom:20px;font-weight:500}#grading-results .result-item{padding:15px;margin:10px 0;background-color:var(--background);border-radius:4px;border-left:4px solid var(--secondary-color)}#grading-results .result-item.error{border-left-color:var(--danger-color)}.settings-section{background:var(--surface);padding:24px;border-radius:8px;box-shadow:var(--shadow);margin-bottom:20px}.settings-section h3{margin-bottom:20px;color:var(--primary-color)}.form-group{margin-bottom:20px}.form-group label{display:block;margin-bottom:8px;font-weight:500}.form-group small{display:block;margin-top:5px;color:var(--text-secondary);font-size:12px}.footer{background:var(--surface);padding:20px 0;margin-top:50px;text-align:center;color:var(--text-secondary);box-shadow:0 -1px 3px #0000001f}@media (max-width: 768px){.header .container{flex-direction:column;gap:15px}.tabs{overflow-x:scroll}.stats-grid{grid-template-columns:1fr}.action-bar{flex-direction:column}}