/* Style B — clear flat illustration. Scoped separately so its locked preview
   cannot change the applied theme, word state, or any active game. */
:root[data-appearance="flat"] {
  color-scheme:light;--bg:#F5FCFA;--paper:#FFFFFF;--text:#073D45;--muted:#4A6E73;
  --primary:#008B7E;--deep:#006E65;--on-primary:#FFFFFF;--line:#D6EAE5;--soft:#DDF5EE;--light:#ECFBF6;--focus:#299F94;
  --orange:#95591E;--orange-bg:#FFF0D4;--red:#AF3D45;--red-bg:#FFEDEE;--blue:#246D88;--blue-bg:#E3F6FD;
  --side-bg:#FFFFFF;--hero-bg:#DFF8F2;--hero-line:#C8EBE3;--art-bg:#FFFFFF;--art-line:#90D4C5;--art-orbit:#A2DDCF;
  --canvas-bg:#F1FFFA;--snake-bg:#EBFBF1;--canvas-alt:#E1F8F0;--canvas-grid:#CFEAE0;--snake-grid:#CAE7D6;
  --canvas-floor:#CEF2E7;--canvas-muted:#4F7E78;--canvas-line:#77B6A9;--canvas-label:#326860;
  --canvas-card:#FFFFFF;--canvas-card-border:#7DCBBB;--canvas-card-shadow:#BFE4D9;
  --canvas-text:#073D45;--canvas-ink:#008B7E;--canvas-pointer:#008B7E;--canvas-basket:#EAC06E;
  --canvas-weave:#B28740;--canvas-rim:#FFDC8E;--snake-body:#61BF90;--snake-tail:#A1DEB6;
  --garden:#E6F8E6;--garden-glow:#CFEED0;
}
html[data-appearance="flat"] :is(.brand-mark,.button){border-radius:14px}
html[data-appearance="flat"] .sidebar{border-right:1px solid #DEEFE9}
html[data-appearance="flat"] .brand-mark{background:#08A991}
html[data-appearance="flat"] .brand-name{color:#073D45;font-weight:750}
html[data-appearance="flat"] .nav-item.active{background:#DCF7ED;color:#007F74;border-radius:14px}
html[data-appearance="flat"] .topbar{background:#F5FCFA;border-color:transparent}
html[data-appearance="flat"] .bottom-nav{background:#FFFFFFF5;box-shadow:0 -6px 25px #08746509;border-color:#E4F2ED}
html[data-appearance="flat"] .bottom-nav button.active{color:#008B7E}
html[data-appearance="flat"] :is(.panel,.book-card,.wrong-row,.result-hero){border-radius:22px;box-shadow:0 5px 24px #08746505}
html[data-appearance="flat"] .book-spine{background:#D6F6EB;color:#007F70}
html[data-appearance="flat"] .modal{border-radius:24px}
html[data-appearance="flat"] .game-shell{border-radius:22px;border-color:#CFE9E0;box-shadow:0 7px 30px #0C87680A}
html[data-appearance="flat"] .pair-card.face-up{border-color:#83CEB8}
html[data-appearance="flat"] .pair-card:not(.face-up):not(.removed){background:#DBF6ED;border-color:#A5DCC9;color:#008B7E}
.flat-home{container:flat / inline-size;width:100%;color:#073D45;font-family:"Noto Sans CJK SC",system-ui,-apple-system,"Segoe UI",sans-serif}
.flat-home *{box-sizing:border-box}
.flat-home button{font:inherit;cursor:pointer}
.flat-hero{min-height:147px;background:linear-gradient(110deg,#E0FBF4,#F0FCFA);border-radius:26px;position:relative;isolation:isolate;overflow:hidden;display:flex;justify-content:center;align-items:center;text-align:center;padding:19px 14px 41px}
.flat-hero-copy{position:relative;z-index:2}
.flat-kicker{font-size:10px;font-weight:700;letter-spacing:.16em;color:#4F8D84;display:none}
.flat-home .flat-hero h1{font-size:36px;line-height:1.28;font-weight:850;letter-spacing:.02em;margin:0;color:#073D45}
.flat-home .flat-hero p{font-size:19px;letter-spacing:.1em;color:#0B7A79;margin:6px 0 0;line-height:1.55}
.flat-hero-note{display:none}
.flat-leaves{position:absolute;left:-15px;bottom:7px;width:93px;height:135px;z-index:1}
.flat-books{position:absolute;right:-2px;bottom:3px;width:111px;height:85px;z-index:1}
.flat-leaves svg,.flat-books svg{width:100%;height:100%;display:block}
.flat-wave{position:absolute;inset:auto 0 0;width:100%;height:68px;z-index:0}
.flat-book{position:relative;z-index:2;display:flex;align-items:center;gap:12px;min-height:76px;background:white;border-radius:21px;padding:13px 16px;margin:-23px 9px 0;box-shadow:0 6px 24px #0A73610C}
.flat-book-icon{display:block;flex:0 0 43px;width:43px;height:45px}.flat-book-icon svg{width:100%;height:100%}
.flat-book-name{flex:1;min-width:0;display:flex;flex-direction:column;gap:1px}
.flat-book-name>span{font-size:12px;color:#547A7B;line-height:1.5}
.flat-book-name strong{font-size:19px;font-weight:750;overflow-wrap:anywhere;line-height:1.5}
.flat-book-name small{font-size:12px;color:#65867E;display:none}
.flat-switch{display:inline-flex;align-items:center;justify-content:center;gap:2px;border:0;border-radius:30px;min-height:43px;padding:8px 13px;background:#008B7E;color:#FFFFFF;font-size:14px!important;font-weight:650!important;white-space:nowrap}
.flat-switch svg{width:17px;height:17px}
.flat-section-head{display:flex;align-items:center;justify-content:space-between;gap:8px;margin:17px 4px 11px}
.flat-home .flat-section-head h2{font-size:19px;font-weight:750;letter-spacing:0;line-height:1.5;color:#073D45}
.flat-section-head h2>span{font-size:17px;color:#12B69D;margin-right:4px}
.flat-section-head>span{font-size:11px;color:#527970;white-space:nowrap}
.flat-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
/* More-specific selectors intentionally override legacy .game-card geometry. */
.flat-home .flat-grid .flat-tile{display:flex;flex-direction:column;align-items:center;justify-content:center;position:relative;text-align:center;min-width:0;width:100%;min-height:134px;margin:0;padding:8px 7px 13px;border:1px solid transparent;border-radius:22px;box-shadow:none;overflow:hidden;transition:transform .15s,box-shadow .15s;background:#D8F8EE;color:#073D45;isolation:isolate}
.flat-home .flat-grid .flat-tile:hover{transform:translateY(-3px);box-shadow:0 9px 25px #0D6E5612;border-color:#91D8C8}
.flat-home .flat-grid .flat-tile:active{transform:translateY(0)}
.flat-home .flat-grid .flat-tile:focus-visible{outline:3px solid #008B7E;outline-offset:3px}
.flat-home .flat-tile h3{font-size:18px;font-weight:750;letter-spacing:0;line-height:1.45;margin:0;color:#073D45}
.flat-home .flat-tile p{display:none;font-size:13px;color:#376E69;line-height:1.6;margin:4px 0 0}
.flat-home .flat-art{display:block;width:min(100%,195px);height:90px;flex:none;margin:0 auto}
.flat-art>svg{width:100%;height:100%;display:block}
.flat-tile-top,.flat-tile-cta{display:none}
.flat-home .flat-grid .flat-link{background:#FFF6D9}
.flat-home .flat-grid .flat-snake{background:#DAF8EE}
.flat-home .flat-grid .flat-mole{background:#FFF0D8}
.flat-home .flat-grid .flat-catch{grid-column:1 / -1;min-height:117px;background:#C5EFFB;padding:7px 12px 12px}
.flat-home .flat-catch .flat-art{height:82px;width:246px;max-width:92%;margin-bottom:0}
.flat-summary{display:flex;align-items:center;justify-content:center;gap:0;padding:16px 0 0;font-size:11px;color:#50756E;line-height:1.5}
.flat-summary>span,.flat-summary>button,.flat-summary>div{flex:1;display:inline-flex;gap:3px;align-items:center;justify-content:center;min-height:32px;padding:0 3px;border:0;border-left:1px solid #D3EAE1;background:none;white-space:nowrap}
.flat-summary>span:first-child{border-left:0}
.flat-summary b{font-size:15px;font-weight:750;color:#007F72}
.flat-summary svg{width:12px;height:12px;color:#007F72;margin-left:1px}
.flat-import{display:block;text-align:center;background:none;border:0;padding:9px 14px;margin:2px auto 0;min-height:44px;color:#397970;font-size:12px!important}
.b-preview{background:#F6FCF9;border:1px solid #D6EBE3;border-radius:25px;padding:12px;color:#073D45;overflow:hidden;box-shadow:0 12px 40px #0A4C4310;isolation:isolate}
.b-preview .flat-home{padding-bottom:0}
.b-preview .flat-home .flat-hero{min-height:148px;padding-bottom:27px}
.b-preview .flat-home .flat-hero h1{font-size:31px}
.b-preview .flat-home .flat-hero p{font-size:17px}
.b-preview .flat-section-head{margin-top:16px}
.b-preview .flat-grid{gap:9px}
.b-preview .flat-home .flat-grid .flat-tile{min-height:129px;padding-top:4px;border-radius:18px}
.b-preview .flat-home .flat-art{height:89px}
.b-preview .flat-home .flat-grid .flat-catch{min-height:106px}
.b-preview .flat-home .flat-catch .flat-art{height:77px}
.b-preview .flat-home .flat-tile h3{font-size:16px}
.b-preview .flat-book{min-height:74px;padding:10px 12px;gap:8px;margin-left:3px;margin-right:3px}
.b-preview .flat-book-name strong{font-size:17px}
.b-preview .flat-summary,.b-preview .flat-import{display:none}
.b-preview .flat-section-head>span{font-size:10px}
.b-preview .flat-hero .flat-books{width:90px}
@container flat (min-width:760px){
 .flat-hero{justify-content:flex-start;text-align:left;min-height:224px;padding:30px 50px 52px;border-radius:28px}
 .flat-kicker{display:inline-block;font-size:11px;margin-bottom:8px}
 .flat-home .flat-hero h1{font-size:46px;letter-spacing:.01em}
 .flat-home .flat-hero p{font-size:21px;margin-top:8px;letter-spacing:.12em}
 .flat-hero-note{display:block;font-size:13px;color:#568179;margin-top:8px}
 .flat-leaves{left:auto;right:24%;width:117px;height:185px;bottom:0;opacity:.72}
 .flat-books{right:5%;bottom:1px;width:230px;height:190px}
 .flat-wave{height:86px}
 .flat-book{min-height:88px;margin:-27px 22px 0;padding:14px 23px;gap:16px;border-radius:21px}
 .flat-book-name>span{font-size:13px}
 .flat-book-name strong{font-size:21px}.flat-book-name small{display:block}
 .flat-book-icon{flex-basis:49px;height:52px}
 .flat-switch{padding:10px 22px;min-height:45px}
 .flat-section-head{margin:24px 3px 15px}.flat-home .flat-section-head h2{font-size:23px}
 .flat-section-head>span{font-size:13px}
 .flat-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
 .flat-home .flat-grid .flat-tile{min-height:193px;padding:14px 20px 18px;border-radius:23px}
 .flat-home .flat-tile h3{font-size:20px}.flat-home .flat-tile p{display:block}
 .flat-home .flat-art{width:205px;height:121px}
 .flat-home .flat-grid .flat-catch{grid-column:3;grid-row:1 / span 2;justify-content:center;min-height:402px;background:#C5EFFB;padding:24px 22px}
 .flat-home .flat-catch .flat-art{height:189px;width:100%;max-width:100%;margin:23px auto 16px}
 .flat-tile-top{display:flex;align-items:center;justify-content:space-between;width:100%;font-size:11px;color:#367E76;margin-bottom:0}
 .flat-tile-top svg{width:19px;height:19px;background:#FFFFFF72;border-radius:50%;padding:3px;color:#2C7A73}
 .flat-catch .flat-tile-top{position:absolute;top:20px;left:21px;width:calc(100% - 42px);font-size:12px}
 .flat-catch .flat-tile-cta{display:inline-flex;align-items:center;gap:7px;border-radius:30px;background:#FFFFFFC7;padding:9px 18px;font-size:13px;color:#086B71;margin-top:20px;font-weight:650}
 .flat-tile-cta svg{width:16px;height:16px}
 .flat-summary{max-width:700px;margin:0 auto;padding-top:20px;font-size:13px}.flat-summary b{font-size:20px}
 .flat-import{font-size:13px!important}
}
@container flat (max-width:315px){
 .flat-home .flat-hero h1{font-size:30px}.flat-home .flat-hero p{font-size:17px}
 .flat-hero{min-height:169px}.flat-books{width:90px}.flat-leaves{width:76px}
 .flat-book{padding:12px 11px;gap:8px;margin-left:3px;margin-right:3px}.flat-book-icon{flex-basis:35px}
 .flat-book-name strong{font-size:17px}.flat-switch{padding:8px 10px;font-size:13px!important}
 .flat-section-head>span{font-size:10px}.flat-home .flat-section-head h2{font-size:17px}
 .flat-grid{gap:9px}.flat-home .flat-grid .flat-tile{min-height:139px;border-radius:18px}
 .flat-home .flat-tile h3{font-size:16px}.flat-home .flat-art{height:98px}
 .flat-summary{font-size:10px}.flat-summary b{font-size:14px}
}
@media(max-width:700px){html[data-appearance="flat"] .content:not(.play-content){padding:10px 14px 86px}html[data-appearance="flat"] .topbar{min-height:58px}html[data-appearance="flat"] .page-title h1{letter-spacing:-.02em}}
@media(prefers-reduced-motion:reduce){.flat-home .flat-grid .flat-tile{transition:none}.flat-home .flat-grid .flat-tile:hover{transform:none}}