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4px;opacity:.85}.join-class-teacher{font-size:13px;margin:0;opacity:.8}.join-code-badge{text-align:center;font-size:13px;color:#888;background:#f3f4f6;border-radius:8px;padding:6px 12px;margin-bottom:20px;letter-spacing:1px}.join-code-badge strong{color:#667eea;font-family:monospace;font-size:15px}.join-toggle{display:flex;border:2px solid #e5e7eb;border-radius:12px;overflow:hidden;margin-bottom:20px}.join-toggle-btn{flex:1;padding:10px;border:none;background:transparent;cursor:pointer;font-size:14px;font-weight:500;color:#888;transition:all .2s}.join-toggle-btn.active{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;font-weight:700}.join-submit-btn{margin-top:8px;background:linear-gradient(135deg,#667eea,#764ba2);font-size:16px;padding:14px}.join-back{text-align:center;margin-top:16px;font-size:14px;color:#888}.join-error-card{text-align:center;max-width:360px}.spinner{width:36px;height:36px;border:4px solid #e5e7eb;border-top-color:#667eea;border-radius:50%;animation:spin .8s linear infinite;margin:0 auto}@keyframes spin{to{transform:rotate(360deg)}}