:root{
  color-scheme:light;
  --paper:#f5f1e8;
  --paper-deep:#ebe3d4;
  --ink:#1b2926;
  --muted:#65716d;
  --line:rgba(27,41,38,.14);
  --green:#174b3f;
  --green-2:#236b59;
  --orange:#d5693e;
  --card:#fffdf8;
  --shadow:0 24px 60px rgba(39,49,44,.12);
}
*{box-sizing:border-box}
html{background:var(--paper);font-family:Inter,"PingFang SC","Microsoft YaHei",system-ui,sans-serif;color:var(--ink);-webkit-tap-highlight-color:transparent}
body{margin:0;min-height:100vh;background:
  radial-gradient(circle at 88% 3%,rgba(213,105,62,.12),transparent 27rem),
  linear-gradient(180deg,#faf7f0 0,var(--paper) 45%,#f0eadf 100%)}
button,input{font:inherit}
button{color:inherit}
[hidden]{display:none!important}
.app-shell{width:min(100%,760px);min-height:100vh;margin:0 auto;padding:env(safe-area-inset-top) 20px env(safe-area-inset-bottom)}
.app-header{height:82px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line)}
.brand{display:flex;align-items:center;gap:11px;border:0;background:transparent;padding:0;text-align:left;cursor:pointer}
.brand-mark{display:grid;place-items:center;width:38px;height:38px;border-radius:12px;background:var(--green);color:#fff9ed;font-family:Georgia,serif;font-size:23px;font-style:italic}
.brand strong{display:block;font-size:16px;letter-spacing:.04em}.brand small{display:block;margin-top:2px;color:var(--muted);font-size:11px}
.icon-button,.sound-button,.close-button{border:1px solid var(--line);background:rgba(255,255,255,.45);cursor:pointer}
.icon-button{width:42px;height:42px;border-radius:50%;font-size:24px}.icon-button.syncing{animation:spin .8s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.view{padding:28px 0 38px}
body.study-mode .app-header,body.study-mode .site-footer{display:none}
body.study-mode .app-shell{min-height:auto}
body.study-mode .view{padding-top:max(10px,env(safe-area-inset-top));padding-bottom:max(14px,env(safe-area-inset-bottom))}
.hero{position:relative;padding:36px 28px 32px;border-radius:28px;color:#f8f3e8;overflow:hidden;background:var(--green);box-shadow:var(--shadow)}
.hero:before,.hero:after{content:"";position:absolute;border:1px solid rgba(255,255,255,.12);border-radius:50%}
.hero:before{width:230px;height:230px;right:-96px;top:-126px}.hero:after{width:130px;height:130px;right:20px;bottom:-94px}
.eyebrow{margin:0 0 10px;color:var(--orange);font-size:11px;font-weight:800;letter-spacing:.18em;text-transform:uppercase}
.hero .eyebrow{color:#efb89e}.hero h1{position:relative;margin:0;font-family:Georgia,"Songti SC",serif;font-size:clamp(34px,9vw,54px);line-height:1.13;font-weight:500;letter-spacing:-.03em}.hero h1 em{color:#efb89e;font-weight:500}
.hero-copy{position:relative;margin:18px 0 24px;max-width:420px;color:#dbe7df;font-size:14px;line-height:1.7}
.primary-button,.reveal-button,.known-button{border:0;border-radius:15px;font-weight:750;cursor:pointer}
.primary-button{position:relative;padding:13px 20px;background:#fff7e9;color:var(--green)}
.notice{margin:18px 0 0;padding:12px 15px;border:1px solid rgba(35,107,89,.25);border-radius:13px;background:rgba(255,255,255,.55);font-size:13px;color:var(--green)}
.section-heading{display:flex;align-items:end;justify-content:space-between;gap:15px;margin:34px 2px 15px}.section-heading span{color:var(--orange);font-size:11px;font-weight:800;letter-spacing:.14em}.section-heading h2{margin:4px 0 0;font-family:Georgia,"Songti SC",serif;font-size:25px;font-weight:500}
.search{display:flex;align-items:center;gap:6px;width:min(48%,230px);border-bottom:1px solid var(--line);padding:7px 2px}.search input{width:100%;border:0;outline:0;background:transparent;color:var(--ink);font-size:13px}.search input::placeholder{color:#8a938f}
.category-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
.category-group{grid-column:1/-1;margin-top:10px;color:var(--muted);font-size:12px;font-weight:750;letter-spacing:.08em}.category-group:first-child{margin-top:0}
.category-card{position:relative;min-height:142px;padding:18px;border:1px solid var(--line);border-radius:20px;background:rgba(255,253,248,.82);text-align:left;cursor:pointer;overflow:hidden;box-shadow:0 8px 26px rgba(39,49,44,.05)}
.category-card:after{content:"→";position:absolute;right:17px;bottom:15px;color:var(--orange);font-size:20px}.category-card:hover{border-color:rgba(23,75,63,.35);transform:translateY(-1px)}
.category-index{display:block;margin-bottom:22px;color:var(--orange);font:italic 18px Georgia,serif}.category-card strong{display:block;padding-right:18px;font-family:Georgia,"Songti SC",serif;font-size:20px;font-weight:500;line-height:1.35}.category-card small{display:block;margin-top:7px;color:var(--muted)}
.empty-state{padding:42px 18px;text-align:center;border:1px dashed var(--line);border-radius:20px}.empty-state strong,.empty-state span{display:block}.empty-state span{margin-top:8px;color:var(--muted);font-size:13px}
.study-topline{display:flex;justify-content:space-between;align-items:center;gap:12px}.text-button{border:0;background:transparent;padding:5px 0;color:var(--green-2);font-size:14px;cursor:pointer}
.study-card{margin-top:12px;min-height:0;padding:24px;border:1px solid var(--line);border-radius:22px;background:var(--card);box-shadow:0 14px 38px rgba(39,49,44,.1);outline:none;display:flex;flex-direction:column}
.study-card:focus-visible{box-shadow:0 0 0 3px rgba(35,107,89,.18),var(--shadow)}
.card-label{display:flex;align-items:center;justify-content:space-between;color:var(--orange);font-size:11px;font-weight:800;letter-spacing:.14em}.sound-button{width:35px;height:35px;border-radius:50%;font-size:12px;color:var(--green)}
.card-question{margin:18px 0 8px;font-family:Georgia,"Songti SC",serif;font-size:clamp(27px,7vw,36px);font-weight:500;line-height:1.4}.question-en,.follow-question-en{color:var(--green-2)}.inline-button{align-self:flex-start;border:0;border-bottom:1px solid currentColor;background:transparent;padding:4px 0;color:var(--muted);font-size:13px;cursor:pointer}
.answer-panel{margin-top:18px}.answer-rule{height:1px;margin-bottom:18px;background:var(--line)}.card-answer{margin:14px 0 6px;font-family:Georgia,"Songti SC",serif;font-size:clamp(20px,5.2vw,27px);line-height:1.52}.answer-zh,.follow-answer{color:var(--muted)}.answer-en,.follow-answer-en{color:var(--green)}
.follow-ups{margin-top:22px}.follow-ups:empty{display:none}.follow-item{margin:0;padding:22px 0 0;border-top:1px solid var(--line)}.follow-item+.follow-item{margin-top:22px}.follow-item .card-question{margin:0 0 8px}.follow-item .card-answer{margin:12px 0 6px}
.study-actions{display:grid;grid-template-columns:1fr 1.35fr 1fr;gap:7px;margin-top:11px}.secondary-button,.known-button{min-height:43px;border-radius:12px;cursor:pointer;font-size:13px}.secondary-button{border:1px solid var(--line);background:rgba(255,255,255,.7)}.known-button{background:var(--orange);color:#fff}.known-button.known{background:var(--green);color:#fff}.study-actions button:disabled{opacity:.4;cursor:not-allowed}.gesture-hint{margin:7px 0 0;text-align:center;color:var(--muted);font-size:10px}
.centered-view{min-height:70vh;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center}.centered-view[hidden]{display:none}.error-symbol{display:grid;place-items:center;width:52px;height:52px;border-radius:50%;background:#f0d8cc;color:#9d4224;font:700 26px Georgia,serif}.centered-view h1{font-family:Georgia,"Songti SC",serif;font-weight:500}.centered-view p{max-width:430px;color:var(--muted);line-height:1.7}
.site-footer{display:flex;justify-content:space-between;gap:12px;padding:18px 2px 28px;border-top:1px solid var(--line);font-size:11px}.site-footer a,.footer-button{color:var(--muted)}.footer-button{border:0;background:transparent;padding:0;cursor:pointer}
.settings-dialog{width:min(92vw,520px);border:1px solid var(--line);border-radius:24px;background:var(--card);color:var(--ink);padding:24px;box-shadow:var(--shadow)}.settings-dialog::backdrop{background:rgba(17,29,26,.52);backdrop-filter:blur(3px)}.settings-dialog form{margin:0}.dialog-heading,.toggle-row{display:flex;align-items:center;justify-content:space-between;gap:16px}.dialog-heading h2{margin:0;font-family:Georgia,"Songti SC",serif;font-size:28px;font-weight:500}.close-button{width:38px;height:38px;border-radius:50%;font-size:25px}.toggle-row{padding:19px 0;border-top:1px solid var(--line)}.toggle-row:first-of-type{margin-top:22px}.toggle-row strong,.toggle-row small{display:block}.toggle-row small{margin-top:4px;color:var(--muted);font-size:11px}.toggle-row input{width:20px;height:20px;accent-color:var(--green)}.danger-button{width:100%;margin-top:8px;padding:12px;border:1px solid #d9a58f;border-radius:13px;background:transparent;color:#9d4224;cursor:pointer}.dialog-note{color:var(--muted);font-size:11px;line-height:1.65}.toast{position:fixed;z-index:50;left:50%;bottom:max(22px,env(safe-area-inset-bottom));transform:translate(-50%,18px);max-width:min(90vw,480px);padding:11px 15px;border-radius:12px;background:#173c34;color:#fff;font-size:12px;opacity:0;pointer-events:none;transition:.2s}.toast.show{opacity:1;transform:translate(-50%,0)}
@media(max-width:520px){.app-shell{padding-left:15px;padding-right:15px}.app-header{height:72px}.view{padding-top:20px}.hero{padding:30px 22px 27px;border-radius:23px}.section-heading{display:block}.search{width:100%;margin-top:15px}.category-card{min-height:130px;padding:16px}.study-card{padding:20px}.card-label{font-size:11px}.sound-button{width:35px;height:35px}.study-actions{grid-template-columns:1fr 1.2fr 1fr}.site-footer{align-items:center;flex-direction:column}}
@media(max-width:365px){.category-list{grid-template-columns:1fr}.category-group{grid-column:1}.study-actions{grid-template-columns:1fr 1fr}.known-button{grid-column:1/-1;grid-row:1}.secondary-button{grid-row:2}.brand small{max-width:170px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;animation:none!important;transition:none!important}}