*{margin:0;padding:0;box-sizing:border-box}:root{--primary: #6366f1;--primary-dark: #4f46e5;--primary-light: #818cf8;--secondary: #10b981;--secondary-dark: #059669;--warning: #f59e0b;--danger: #ef4444;--bg: #f8fafc;--bg-dark: #1e293b;--surface: #ffffff;--text: #1e293b;--text-light: #64748b;--text-lighter: #94a3b8;--border: #e2e8f0;--shadow: 0 1px 3px 0 rgb(0 0 0 / .1), 0 1px 2px -1px rgb(0 0 0 / .1);--shadow-md: 0 4px 6px -1px rgb(0 0 0 / .1), 0 2px 4px -2px rgb(0 0 0 / .1);--shadow-lg: 0 10px 15px -3px rgb(0 0 0 / .1), 0 4px 6px -4px rgb(0 0 0 / .1);--radius: 8px;--radius-lg: 12px}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Hiragino Sans GB,Microsoft 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var(--primary)}.btn-outline:hover{background:var(--primary);color:#fff}.btn-danger{background:var(--danger);color:#fff}.btn-danger:hover{background:#dc2626}.btn-ghost{background:transparent;color:var(--text-light)}.btn-ghost:hover{background:#f1f5f9;color:var(--text)}.btn-sm{padding:6px 12px;font-size:13px}.btn-lg{padding:14px 28px;font-size:16px}.btn:disabled{opacity:.5;cursor:not-allowed;transform:none!important}.input,.select,.textarea{width:100%;padding:10px 14px;border:1.5px solid var(--border);border-radius:var(--radius);font-size:14px;transition:all .2s;background:#fff}.input:focus,.select:focus,.textarea:focus{border-color:var(--primary);box-shadow:0 0 0 3px #6366f11a}.textarea{resize:vertical;min-height:80px}.label{display:block;margin-bottom:6px;font-size:14px;font-weight:500;color:var(--text)}.card{background:var(--surface);border-radius:var(--radius-lg);padding:24px;box-shadow:var(--shadow)}.badge{display:inline-block;padding:4px 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20px;text-align:left;font-size:14px}.table th{background:#f8fafc;font-weight:600;color:var(--text-light);font-size:13px;text-transform:uppercase;letter-spacing:.5px;border-bottom:1px solid var(--border)}.table td{border-bottom:1px solid #f1f5f9}.table tr:last-child td{border-bottom:none}.table tr:hover td{background:#f8fafc}.table-actions{display:flex;gap:8px}.empty-state{text-align:center;padding:60px 20px;color:var(--text-light)}.empty-state .empty-icon{font-size:64px;margin-bottom:16px}.empty-state h3{font-size:18px;color:var(--text);margin-bottom:8px}.modal-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#00000080;display:flex;align-items:center;justify-content:center;z-index:1000;padding:20px}.modal{background:#fff;border-radius:var(--radius-lg);width:100%;max-width:560px;max-height:90vh;overflow-y:auto;box-shadow:0 25px 50px -12px #00000040}.modal-header{padding:20px 24px;border-bottom:1px solid var(--border);display:flex;justify-content:space-between;align-items:center}.modal-header h2{font-size:20px}.modal-close{background:transparent;font-size:24px;color:var(--text-lighter);cursor:pointer;padding:4px 8px;border-radius:4px}.modal-close:hover{background:#f1f5f9;color:var(--text)}.modal-body{padding:24px}.modal-footer{padding:16px 24px;border-top:1px solid var(--border);display:flex;justify-content:flex-end;gap:12px}.form-row{margin-bottom:18px}.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}.word-library-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:20px;margin-bottom:24px}.library-card{background:#fff;border-radius:var(--radius-lg);padding:24px;box-shadow:var(--shadow);transition:all .2s;border:2px solid transparent}.library-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg);border-color:var(--primary-light)}.library-card 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.2s;font-size:16px;text-align:center}.match-item:hover{border-color:var(--primary-light);background:#f5f3ff}.match-item.selected{border-color:var(--primary);background:#eef2ff;color:var(--primary-dark);font-weight:500}.match-item.matched{border-color:var(--secondary);background:#ecfdf5;color:var(--secondary-dark);opacity:.7;cursor:not-allowed}.match-item.wrong{border-color:var(--danger);background:#fef2f2;animation:shake .4s}@keyframes shake{0%,to{transform:translate(0)}25%{transform:translate(-6px)}75%{transform:translate(6px)}}.classroom-layout{display:grid;grid-template-columns:1fr 320px;gap:20px;height:calc(100vh - 120px)}.classroom-main{background:#fff;border-radius:var(--radius-lg);padding:32px;box-shadow:var(--shadow);display:flex;flex-direction:column;overflow:hidden}.classroom-sidebar{display:flex;flex-direction:column;gap:16px;overflow:hidden}.classroom-panel{background:#fff;border-radius:var(--radius-lg);padding:20px;box-shadow:var(--shadow);flex:1;display:flex;flex-direction:column;overflow:hidden}.classroom-panel h3{font-size:15px;margin-bottom:16px;display:flex;align-items:center;gap:8px}.classroom-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:24px;padding-bottom:16px;border-bottom:1px solid var(--border)}.classroom-code{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;padding:10px 20px;border-radius:var(--radius);font-size:18px;font-weight:700;letter-spacing:2px}.student-list{display:flex;flex-direction:column;gap:8px;margin-bottom:16px}.student-item{display:flex;align-items:center;gap:10px;padding:10px 12px;background:#f8fafc;border-radius:var(--radius);font-size:14px}.student-item .status-dot{width:8px;height:8px;border-radius:50%;background:var(--secondary)}.chat-messages{flex:1;overflow-y:auto;margin-bottom:12px;padding-right:8px;display:flex;flex-direction:column;gap:10px}.chat-message{max-width:85%;padding:8px 12px;border-radius:12px;font-size:13px;line-height:1.5}.chat-message.teacher{background:#eef2ff;color:var(--primary-dark);align-self:flex-start;border-bottom-left-radius:4px}.chat-message.student{background:#f0f9ff;color:#075985;align-self:flex-end;border-bottom-right-radius:4px}.chat-message .sender{font-size:11px;opacity:.7;margin-bottom:2px}.chat-input{display:flex;gap:8px}.teacher-controls{display:flex;gap:10px;flex-wrap:wrap;padding:16px 0;border-top:1px solid var(--border);margin-top:auto}.mode-switcher{display:flex;background:#f1f5f9;border-radius:var(--radius);padding:4px;gap:2px}.mode-btn{padding:8px 14px;border-radius:6px;background:transparent;font-size:13px;font-weight:500;color:var(--text-light);transition:all .2s}.mode-btn.active{background:#fff;color:var(--primary);box-shadow:var(--shadow)}.classroom-word-area{flex:1;display:flex;align-items:center;justify-content:center}.annotation-area{margin-top:16px;padding:16px;background:#fffbeb;border-radius:var(--radius);border-left:4px solid var(--warning)}.annotation-area h4{font-size:13px;color:#b45309;margin-bottom:8px}.annotation-text{font-size:14px;color:#92400e;line-height:1.6}@media (max-width: 1024px){.classroom-layout{grid-template-columns:1fr;height:auto}}@media (max-width: 768px){.sidebar{transform:translate(-100%);transition:transform .3s}.sidebar.open{transform:translate(0)}.main-content{margin-left:0;padding:20px 16px}.role-cards{flex-direction:column}.form-grid{grid-template-columns:1fr}.matching-grid{gap:20px}.flashcard{height:320px}.flashcard-front .word{font-size:40px}}