:root{color-scheme:light dark;--border: #d8d3c9;--bg: #fdfcf9;--panel-bg: #ffffff;--text: #2a2620;--muted: #837c6d;--accent: #a8763e;--accent-bg: #f4e8d6}*{box-sizing:border-box}body{margin:0;font-family:-apple-system,BlinkMacSystemFont,Helvetica Neue,PingFang TC,Noto Sans TC,sans-serif;background:var(--bg);color:var(--text)}.layout{display:flex;height:100vh}.chat-panel,.book-panel{height:100%;overflow:hidden;display:flex;flex-direction:column}.chat-panel{position:relative;flex:1 1 40%;border-right:1px solid var(--border);min-width:320px}.chat-panel>*{position:relative;z-index:1}.book-panel{position:relative;flex:1 1 60%;background:var(--panel-bg);min-width:320px}.book-panel:before{content:"";position:absolute;top:0;right:0;bottom:0;left:0;background:url(https://cdn.tatlerasia.com/tatlerasia/i/2025/06/16120629-batch-during-practice-5_cover_1067x1600.jpg) center / cover no-repeat;opacity:1;transition:opacity .8s ease;z-index:0}.book-panel.has-book:before{opacity:0}.book-panel>*{position:relative;z-index:1}header{padding:1rem 1.25rem;border-bottom:1px solid var(--border)}header h1{margin:0;font-size:1.1rem;font-weight:600}header h1.home-link{display:inline-block;cursor:pointer}.messages{flex:1;overflow-y:auto;padding:1rem 1.25rem;display:flex;flex-direction:column;gap:1rem}.message{max-width:90%;line-height:1.6;white-space:pre-wrap}.message.user{align-self:flex-end;background:var(--accent-bg);padding:.5rem .75rem}.message.assistant{align-self:flex-start;background:var(--panel-bg);border:1px solid var(--border);padding:.6rem .9rem}.message.pending{color:var(--muted);font-style:italic}.point{margin-bottom:.9rem}.point:last-child{margin-bottom:0}.point-header{margin:0 0 .25rem;font-size:1rem;font-weight:600;color:var(--text)}.suggestions{margin:auto 0;display:flex;flex-direction:column;align-items:flex-start;gap:.6rem}.suggestions-label{margin:0 0 .2rem;color:var(--muted);font-size:.9rem}.suggestion{text-align:left;padding:.55rem .9rem;border:1px solid var(--border);background:var(--panel-bg);color:var(--text);cursor:pointer;font-size:.95rem;line-height:1.4}.suggestion:hover{border-color:var(--accent);background:var(--accent-bg)}.citation-line{display:block;margin:.3rem 0 .6rem;color:var(--accent);font-size:.85rem;cursor:pointer;text-decoration:underline dotted}.citation-line:hover{color:var(--text);background:var(--accent-bg)}.ask-form{display:flex;gap:.5rem;padding:1rem 1.25rem;border-top:1px solid var(--border)}.ask-form input{flex:1;padding:.6rem .75rem;border:1px solid var(--border);font-size:1rem;background:var(--panel-bg);color:var(--text)}.ask-form button{padding:.6rem 1rem;border:none;background:var(--accent);color:#fff;cursor:pointer;font-size:1rem}.ask-form button:disabled{opacity:.5;cursor:default}.book-view{height:100%;display:flex;flex-direction:column;background:var(--panel-bg);animation:book-view-fade-in .8s ease}@keyframes book-view-fade-in{0%{opacity:0}to{opacity:1}}.book-caption{padding:.75rem 1.25rem;border-bottom:1px solid var(--border);display:flex;align-items:center;gap:.75rem;font-size:.9rem;color:var(--muted)}.book-cover{width:36px;height:50px;object-fit:cover;border:1px solid var(--border);flex-shrink:0}.book-caption-text{flex:1;display:flex;justify-content:space-between;gap:1rem}.book-caption #book-title{color:var(--text);font-weight:600}.book-pdf-wrap{flex:1;min-height:0}