*,*:before,*:after{box-sizing:border-box}html,body{margin:0;padding:0;height:100vh;overflow:hidden;background:#fff}#app{height:100%}.root[data-v-2d7ad3e3]{height:100vh;display:flex;flex-direction:column;background:#fff;color:#111;font-family:-apple-system,sans-serif}.header[data-v-2d7ad3e3]{display:flex;align-items:center;justify-content:space-between;padding:0 20px;height:56px;background:#fff;border-bottom:1px solid #e5e5e5;flex-shrink:0}.logo[data-v-2d7ad3e3]{font-size:22px}.header h1[data-v-2d7ad3e3]{font-size:16px;font-weight:700;margin:0}.search-input[data-v-2d7ad3e3]{background:#f5f5f5;border:1px solid #eee;border-radius:8px;padding:6px 12px;font-size:13px;width:240px;outline:none}.new-btn[data-v-2d7ad3e3]{background:#0d9488;color:#fff;border:none;border-radius:8px;padding:7px 14px;font-size:13px;cursor:pointer}.layout[data-v-2d7ad3e3]{flex:1;display:grid;grid-template-columns:280px 1fr;overflow:hidden}.sidebar[data-v-2d7ad3e3]{background:#fafafa;border-right:1px solid #e5e5e5;display:flex;flex-direction:column;overflow:hidden}.tabs[data-v-2d7ad3e3]{display:flex;gap:0;border-bottom:1px solid #e5e5e5}.tabs button[data-v-2d7ad3e3]{flex:1;background:transparent;border:none;padding:10px;font-size:13px;color:#666;cursor:pointer}.tabs button.active[data-v-2d7ad3e3]{color:#0d9488;font-weight:700;border-bottom:2px solid #0d9488}.msg-list[data-v-2d7ad3e3],.contact-list[data-v-2d7ad3e3]{overflow-y:auto;flex:1}.chat-item[data-v-2d7ad3e3]{display:flex;align-items:center;gap:10px;padding:10px 12px;cursor:pointer;border-bottom:1px solid #f0f0f0}.chat-item[data-v-2d7ad3e3]:hover{background:#f5f5f5}.chat-item.active[data-v-2d7ad3e3]{background:#f0fdfa}.chat-avatar[data-v-2d7ad3e3]{width:36px;height:36px;border-radius:50%;color:#fff;font-size:13px;font-weight:700;display:flex;align-items:center;justify-content:center;flex-shrink:0}.chat-info[data-v-2d7ad3e3]{flex:1;overflow:hidden}.chat-name[data-v-2d7ad3e3]{display:block;font-size:14px;font-weight:600}.chat-preview[data-v-2d7ad3e3]{display:block;font-size:12px;color:#999;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.chat-badge[data-v-2d7ad3e3]{background:#ef4444;color:#fff;font-size:10px;font-weight:700;padding:2px 6px;border-radius:100px}.contact-item[data-v-2d7ad3e3]{display:flex;align-items:center;gap:10px;padding:10px 12px;border-bottom:1px solid #f0f0f0}.contact-avatar[data-v-2d7ad3e3]{width:32px;height:32px;border-radius:50%;color:#fff;font-size:12px;font-weight:700;display:flex;align-items:center;justify-content:center}.contact-name[data-v-2d7ad3e3]{display:block;font-size:14px}.contact-student[data-v-2d7ad3e3]{display:block;font-size:11px;color:#999}.content[data-v-2d7ad3e3]{display:flex;flex-direction:column;overflow:hidden}.chat-header[data-v-2d7ad3e3]{padding:12px 16px;border-bottom:1px solid #e5e5e5}.chat-title[data-v-2d7ad3e3]{font-size:15px;font-weight:700}.chat-subtitle[data-v-2d7ad3e3]{font-size:12px;color:#999;margin-left:8px}.chat-messages[data-v-2d7ad3e3]{flex:1;overflow-y:auto;padding:16px;display:flex;flex-direction:column;gap:10px}.msg-bubble[data-v-2d7ad3e3]{max-width:70%;padding:10px 14px;border-radius:12px;font-size:14px;line-height:1.5}.msg-bubble[data-v-2d7ad3e3]:not(.self){background:#f5f5f5;align-self:flex-start}.msg-bubble.self[data-v-2d7ad3e3]{background:#0d9488;color:#fff;align-self:flex-end}.msg-time[data-v-2d7ad3e3]{display:block;font-size:11px;color:#999;margin-top:4px}.msg-bubble.self .msg-time[data-v-2d7ad3e3]{color:#ffffffb3}.composer[data-v-2d7ad3e3]{display:flex;gap:8px;padding:12px 16px;border-top:1px solid #e5e5e5}.composer-input[data-v-2d7ad3e3]{flex:1;background:#f5f5f5;border:1px solid #eee;border-radius:8px;padding:10px 14px;font-size:14px;outline:none}.send-btn[data-v-2d7ad3e3]{background:#0d9488;color:#fff;border:none;border-radius:8px;padding:10px 20px;font-size:14px;cursor:pointer}