:root{color-scheme:light;--bg:#f4efe6;--panel:rgba(255,252,247,0.92);--panel-strong:#fffdf8;--ink:#231815;--muted:#6d5c4d;--line:rgba(78,52,31,0.12);--accent:#c96c2d;--accent-deep:#8f3f14;--green:#2f7d57;--yellow:#b17a10;--red:#aa4c32;--shadow:0 18px 40px rgba(87,47,22,0.12);--radius:24px;--font-heading:Georgia,"Times New Roman",serif;--font-body:"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif}*{box-sizing:border-box}html{min-height:100%;background:radial-gradient(circle at top left,rgba(241,198,156,.45),transparent 28%),radial-gradient(circle at top right,rgba(236,224,186,.35),transparent 32%),linear-gradient(180deg,#f8f1e8,#efe4d6)}body{margin:0;min-height:100vh;color:var(--ink);font-family:var(--font-body)}a{color:inherit;text-decoration:none}button,input,select{font:inherit}.shell{width:min(1180px,calc(100% - 32px));margin:0 auto;padding:24px 0 48px}.hero{background:linear-gradient(145deg,rgba(255,248,240,.92),rgba(253,245,234,.84));border:1px solid var(--line);border-radius:32px;box-shadow:var(--shadow);padding:28px}.hero h1,.section-title,.word-text{font-family:var(--font-heading)}.hero h1{margin:0;font-size:clamp(2rem,4vw,3.5rem);line-height:1.02}.hero p{color:var(--muted);max-width:58ch;line-height:1.7}.grid{display:grid;grid-gap:20px;gap:20px}.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}.panel{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:22px}.panel-soft{background:rgba(255,255,255,.58)}.stats{display:grid;grid-gap:14px;gap:14px;grid-template-columns:repeat(4,minmax(0,1fr));margin-top:18px}.stat-card{padding:18px;border-radius:22px;background:rgba(255,255,255,.7);border:1px solid var(--line)}.stat-card strong{display:block;font-size:1.9rem;margin-bottom:6px}.chip-row{display:flex;gap:10px;flex-wrap:wrap}.chip{padding:8px 12px;border-radius:999px;border:1px solid var(--line);color:var(--muted);background:rgba(255,255,255,.65);font-size:.92rem}.section-title{margin:0 0 12px;font-size:1.5rem}.book-list,.chapter-list{display:grid;grid-gap:12px;gap:12px}.book-card,.upload-box{padding:16px 18px;border-radius:18px;background:rgba(255,255,255,.72);border:1px solid var(--line)}.book-switcher{display:grid;grid-gap:12px;gap:12px;grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}.book-switch{text-align:left;cursor:pointer;transition:transform .14s ease,border-color .14s ease,background .14s ease}.book-switch:hover{transform:translateY(-1px)}.book-switch-active{border-color:rgba(47,125,87,.38);background:rgba(241,249,244,.96)}.upload-box input[type=file]{width:100%;margin-top:12px}.notice{padding:12px 14px;border-radius:16px;font-size:.95rem}.notice-success{background:rgba(47,125,87,.12);color:var(--green)}.notice-error{background:rgba(170,76,50,.12);color:var(--red)}.chapter-card{display:flex;gap:12px;align-items:center;padding:14px 16px;border-radius:18px;background:rgba(255,255,255,.68);border:1px solid var(--line)}.chapter-card input{width:18px;height:18px}.stack{display:grid;grid-gap:16px;gap:16px}.queue{display:inline-flex;align-items:center;gap:6px;border-radius:999px;padding:6px 10px;font-size:.82rem}.queue-due{color:var(--red);background:rgba(211,93,47,.12)}.queue-learning{color:var(--yellow);background:rgba(190,140,46,.14)}.queue-new{color:var(--green);background:rgba(47,125,87,.12)}.word-card{min-height:440px;display:grid;grid-gap:18px;gap:18px;align-content:space-between}.word-meta{display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;color:var(--muted);font-size:.95rem}.word-text{font-size:clamp(2.8rem,10vw,5rem);line-height:.92;margin:10px 0 4px}.phonetic{color:var(--accent-deep);font-size:1.1rem}.definition{font-size:1.12rem;line-height:1.75;color:var(--muted)}.answer-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));grid-gap:12px;gap:12px}.action{border:0;border-radius:20px;padding:14px 16px;min-height:58px;cursor:pointer;transition:transform .14s ease,opacity .14s ease;color:#fff7f2}.action:hover{transform:translateY(-1px)}.action-again{background:linear-gradient(135deg,#be5a3d,#934027)}.action-hard{background:linear-gradient(135deg,#cf9334,#aa7111)}.action-good{background:linear-gradient(135deg,#3d8d67,#2a6d4d)}.action-easy{background:linear-gradient(135deg,#5e7fd2,#3c5bab)}.tiny{color:var(--muted);font-size:.9rem}.session-progress{width:100%;height:10px;background:rgba(104,66,35,.08);border-radius:999px;overflow:hidden}.session-progress>span{display:block;height:100%;background:linear-gradient(90deg,var(--accent),#df9c3a)}.empty{text-align:center;padding:40px 18px;color:var(--muted)}@media (max-width:900px){.answer-grid,.grid-2,.stats{grid-template-columns:1fr}.shell{width:min(100% - 20px,760px);padding-top:16px}.hero,.panel{padding:18px;border-radius:24px}.word-card{min-height:360px}}