@media(max-width:900px){
  .chat-sidebar{position:fixed;inset:0 auto 0 0;transform:translateX(-102%);transition:transform .2s ease;box-shadow:var(--shadow)}
  .chat-sidebar.open{transform:translateX(0)}.sidebar-head #sidebarClose{display:block}.sidebar-backdrop{position:fixed;inset:0;background:rgba(0,0,0,.38);z-index:25}.sidebar-backdrop.open{display:block}
  .mobile-chat-header{display:flex;height:58px;align-items:center;justify-content:space-between;padding:8px 12px;border-bottom:1px solid var(--border);background:var(--surface)}
  .mobile-brand{display:flex;align-items:center;gap:7px;text-decoration:none;font-weight:700}.mobile-brand img{width:29px;height:29px}
  .empty-state{min-height:calc(100vh - 280px)}.empty-state h1{font-size:30px}
  .composer-zone{padding-left:10px;padding-right:10px}.message-list{padding-top:20px}.message-user .message-inner{max-width:88%}
  .jump-latest{left:50%}
}
@media(max-width:520px){
  .conversation-column{width:calc(100% - 22px)}.empty-state h1{font-size:27px}.composer{border-radius:17px}.composer textarea{font-size:16px}.model-selector-btn{max-width:160px}.model-selector-btn #selectedModelName{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.quick-actions{justify-content:flex-start;overflow:auto;flex-wrap:nowrap;padding-bottom:3px}.quick-actions button{white-space:nowrap}.message-text{font-size:15px}.message-user .message-inner{max-width:92%}.settings-card{padding:20px;border-radius:16px}
}