:root{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif;color:#18312a;background:#f4f7f3;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased;--green: #153f32;--green-soft: #dfece3;--paper: #fffdf8;--ink: #18312a;--muted: #6d7a73;--line: #d9e1dc;--gold: #d8a83f;--red: #c94b3d;--blue: #3f5d86}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh;background:radial-gradient(circle at top left,rgba(216,168,63,.16),transparent 34%),linear-gradient(180deg,#eef6ef,#f7f6f1 58%,#f3f5f7)}button,input,textarea{font:inherit}button{min-height:48px;border:0;border-radius:10px;color:var(--ink);background:#e9eee9;cursor:pointer;touch-action:manipulation}button:disabled{cursor:default;opacity:.68}.app{width:min(100%,520px);min-height:100dvh;margin:0 auto;padding:calc(12px + env(safe-area-inset-top)) 16px calc(18px + env(safe-area-inset-bottom))}.topbar{position:sticky;top:0;z-index:3;display:grid;grid-template-columns:48px 1fr auto;align-items:center;gap:10px;padding:8px 0 12px;-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px)}.topbar h1{margin:0;text-align:center;font-size:21px;font-weight:800}.icon-button{min-height:44px;border-radius:999px;color:#fff;background:var(--green);font-weight:800}.total-count{min-width:58px;color:var(--muted);font-size:14px;text-align:right}.card{border:1px solid rgba(21,63,50,.1);border-radius:8px;background:#fffdf8eb;box-shadow:0 14px 36px #17312a17}.home{display:grid;gap:14px}.hero{min-height:154px;padding:22px;display:flex;flex-direction:column;justify-content:center;color:#fff;background:linear-gradient(135deg,#153f32f5,#20523ae6),var(--green)}.hero strong{margin-top:6px;font-size:56px;line-height:1}.hero span{margin-top:10px;color:#ffffffd1}.eyebrow{margin:0;color:var(--muted);font-size:13px;font-weight:800}.hero .eyebrow{color:#ffffffb8}.stats-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.stat{min-height:92px;padding:16px;display:flex;flex-direction:column;justify-content:space-between}.stat span{color:var(--muted);font-size:14px}.stat strong{font-size:30px}.home-actions{display:grid;gap:10px}.offline-card{padding:16px;display:grid;gap:12px}.offline-card strong{display:block;margin-top:5px;font-size:18px}.offline-card span,.offline-card small,.check-hint,.cache-names{color:var(--muted);font-size:14px;line-height:1.55}.offline-card button{color:#fff;background:var(--green);font-weight:900}.action-button{width:100%;min-height:56px;font-size:17px;font-weight:800}.primary{color:#fff;background:var(--green)}.secondary{color:var(--green);background:var(--green-soft)}.quick-row,.reveal-buttons,.grade-actions,.bottom-actions{display:grid;gap:10px}.quick-row{grid-template-columns:repeat(2,minmax(0,1fr))}.quick-row button{color:var(--green);background:#fff;border:1px solid var(--line);font-weight:800}.study-screen,.list-screen{display:grid;gap:14px}.study-card,.write-card,.quiz-card{padding:18px}.card-meta{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:12px;color:var(--muted);font-size:13px}.card-meta span{padding:5px 9px;border-radius:999px;background:#edf1ed}.favorite-button{min-height:42px;padding:0 14px;color:var(--blue);background:#ecf1f7;font-weight:800}.favorite-button.active{color:#6f4a00;background:#fff1c9}.formula-name{margin:16px 0 18px;font-size:34px;line-height:1.18;font-weight:900}.reveal-buttons{grid-template-columns:1fr;margin:18px 0}.reveal-buttons button{color:var(--green);background:#edf5ee;font-weight:800}.answer-block{margin-top:12px;padding:14px;border:1px solid var(--line);border-radius:8px;background:#fff}.answer-block h3{margin:0 0 8px;color:var(--green);font-size:15px}.answer-block p{margin:0;font-size:17px;line-height:1.7}.bottom-actions{position:sticky;bottom:calc(12px + env(safe-area-inset-bottom));grid-template-columns:repeat(3,minmax(0,1fr));padding:10px;border-radius:14px;background:#f4f7f3db;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px)}.bottom-actions button,.grade-actions button{min-height:54px;color:#fff;font-weight:900}.danger{background:var(--red)}.warn{background:var(--gold)}.success{background:#1f7a4d}.write-label{display:grid;gap:8px;margin-bottom:14px;color:var(--muted);font-size:15px;font-weight:800}textarea,input{width:100%;border:1px solid var(--line);border-radius:8px;background:#fff;color:var(--ink);outline:0}textarea{min-height:112px;padding:12px;resize:vertical;font-size:16px;line-height:1.55}input{min-height:48px;padding:0 14px;font-size:16px}textarea:focus,input:focus{border-color:var(--green);box-shadow:0 0 0 3px #153f321f}.grade-actions{margin-top:14px;grid-template-columns:1fr}.segmented{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;padding:6px;border-radius:12px;background:#e7eee8}.segmented button{min-height:44px;border-radius:8px;background:transparent;color:var(--muted);font-weight:900}.segmented button.active{color:#fff;background:var(--green)}.option-list{display:grid;gap:10px}.option-list button{min-height:62px;padding:12px;border:1px solid var(--line);background:#fff;text-align:left;line-height:1.5}.option-list .correct-option{border-color:#1f7a4d;background:#dcf3e5;color:#11562e}.option-list .wrong-option{border-color:var(--red);background:#fde5e1;color:#812b23}.feedback{margin:14px 0;padding:12px;border-radius:8px;font-weight:800;line-height:1.5}.feedback.good{color:#11562e;background:#dcf3e5}.feedback.bad{color:#812b23;background:#fde5e1}.search-card{position:sticky;top:68px;z-index:2;padding:12px}.filter-row{display:flex;gap:8px;overflow-x:auto;padding-top:10px;scrollbar-width:none}.filter-row::-webkit-scrollbar{display:none}.filter-row button{flex:0 0 auto;min-height:40px;padding:0 13px;border-radius:999px;color:var(--muted);background:#eef2ef;font-weight:800}.filter-row button.active{color:#fff;background:var(--green)}.formula-list{display:grid;gap:10px}.list-item{overflow:hidden}.list-main{width:100%;min-height:72px;padding:14px;display:flex;align-items:center;justify-content:space-between;gap:12px;border-radius:8px;background:transparent;text-align:left}.list-main span{min-width:0;display:grid;gap:5px}.list-main strong{font-size:18px}.list-main small{color:var(--muted)}.list-main em{flex:0 0 auto;color:var(--blue);font-size:13px;font-style:normal;font-weight:900}.list-detail{padding:0 14px 14px}.empty-state{padding:22px;text-align:center}.empty-state h2{margin:0 0 8px}.empty-state p{margin:0;color:var(--muted);line-height:1.6}.offline-check{padding:18px}.offline-check h2{margin:8px 0 16px;font-size:24px;line-height:1.3}.check-list{display:grid;gap:10px;margin-bottom:14px}.check-item{min-height:58px;padding:12px;display:flex;align-items:center;gap:10px;border-radius:8px;background:#f1f4f1}.check-item span{flex:0 0 auto;min-width:46px;padding:5px 8px;border-radius:999px;color:#fff;text-align:center;font-size:13px;font-weight:900}.check-item.passed span{background:#1f7a4d}.check-item.waiting span{background:var(--gold)}.check-item strong{font-size:15px}.cache-names{word-break:break-all}@media(min-width:430px){.reveal-buttons,.grade-actions{grid-template-columns:repeat(3,minmax(0,1fr))}}