:root{
 --paper:#fff;--ink:#17211f;--body:#34423d;--muted:#66736d;--faint:#909b96;
 --line:#dfe5e2;--line2:#cbd5d1;--accent:#2d6483;--accent2:#6d617f;
 --green:#527767;--rose:#8b5f70;--blue:#486f94;--surface:#fcfdfd;
 --sans:ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans TC","Noto Sans JP","Hiragino Sans",Arial,sans-serif;
 --serif:"Noto Serif TC","Noto Serif JP","Yu Mincho","Hiragino Mincho ProN",Georgia,serif;
}
html[data-theme="dark"]{
 --paper:#111716;--ink:#edf3f0;--body:#cbd5d0;--muted:#aebbb5;--faint:#83918b;
 --line:#34413d;--line2:#4a5a53;--accent:#8fc5e3;--accent2:#c1acd0;
 --green:#8fc3ab;--rose:#d4a0b6;--blue:#a2bde1;--surface:#161d1b;
}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.82 var(--sans);text-rendering:optimizeLegibility;overflow-x:clip}
body::before{content:"";position:fixed;inset:0;z-index:-1;pointer-events:none;background-image:radial-gradient(circle at 20% 20%,rgba(25,45,38,.010) .45px,transparent .55px),radial-gradient(circle at 70% 70%,rgba(25,45,38,.007) .4px,transparent .55px);background-size:9px 9px,13px 13px}
html[data-theme="dark"] body::before{display:none}a{color:inherit}button{font:inherit}ruby{ruby-position:over}rt{font-size:.56em;line-height:1;color:var(--faint);font-weight:450}.skip{position:absolute;left:12px;top:-80px;z-index:999;background:#111;color:#fff;padding:8px 12px}.skip:focus{top:12px}
.site-nav{position:sticky;top:0;z-index:90;background:color-mix(in srgb,var(--paper) 96%,transparent);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.nav-inner{width:min(1120px,calc(100% - 32px));min-height:68px;margin:auto;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:20px}.brand{display:flex;align-items:center;gap:10px;text-decoration:none;min-width:0}.mark{width:38px;height:38px;display:grid;place-items:center;background:#2e6f9f;border:1px solid #20587f;color:#fff;font:700 21px/1 var(--serif);box-shadow:3px 3px 0 #dbeaf3}.brand strong{font-size:13px}.brand small{display:block;color:var(--muted);font-size:9px}.current-topic{text-align:center;font-size:13px;font-weight:850;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:420px}.nav-actions{display:flex;justify-content:flex-end;gap:8px}.nav-btn{height:36px;min-width:36px;border:1px solid var(--line2);background:transparent;color:var(--ink);cursor:pointer;padding:0 10px}
.page{width:min(1120px,calc(100% - 40px));margin:auto}.hero{padding:58px 0 46px;border-bottom:1px solid var(--line)}.eyebrow{margin:0;color:var(--accent);font-size:10px;font-weight:900;letter-spacing:.16em}.hero h1{margin:14px 0 12px;font:700 clamp(38px,5vw,64px)/1.12 var(--serif);letter-spacing:-.035em}.hero h1 rt{font-size:.25em}.meaning{margin:0;color:var(--body);font-size:clamp(18px,2vw,24px);line-height:1.65;max-width:850px}.hero-grid{display:grid;grid-template-columns:minmax(0,1fr) 290px;gap:42px;align-items:end;margin-top:28px}.lead{margin:0!important;color:var(--muted);font-size:15px;line-height:1.9;max-width:760px}.hero-note{padding:14px 0 0 18px;border-left:2px solid var(--line2)}.hero-note span,.small-label{display:block;color:var(--faint);font-size:9px;font-weight:900;letter-spacing:.12em}.hero-note strong{display:block;margin-top:6px;font-size:17px;line-height:1.6}.meta{display:flex;flex-wrap:wrap;gap:8px 16px;margin-top:24px;color:var(--muted);font-size:11px}.reading-nav{position:sticky;top:68px;z-index:70;background:color-mix(in srgb,var(--paper) 96%,transparent);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}.reading-nav-inner{display:flex;gap:22px;overflow:auto;scrollbar-width:none}.reading-nav-inner::-webkit-scrollbar{display:none}.reading-nav a{flex:0 0 auto;padding:13px 0 11px;text-decoration:none;color:var(--muted);font-size:11px;font-weight:850;border-bottom:2px solid transparent}.reading-nav a.active{color:var(--ink);border-color:var(--ink)}
.section{padding:68px 0;border-bottom:1px solid var(--line)}.section-head{max-width:820px;margin:0 0 32px}.kicker{margin:0 0 7px;color:var(--accent);font-size:10px;font-weight:900;letter-spacing:.13em}.section h2{margin:0;font:700 clamp(29px,3vw,40px)/1.3 var(--serif);letter-spacing:-.018em}.section-intro{margin:11px 0 0;color:var(--muted);max-width:720px}.rule-line{border-top:2px solid var(--ink)}.note{width:min(720px,100%);margin:24px 0 0 auto;padding:12px 0 0 16px;border-left:2px solid var(--line2)}.note span{color:var(--faint);font-size:9px;font-weight:900;letter-spacing:.12em}.note p{margin:5px 0 0!important;color:var(--muted)!important;font-size:13px!important}.jp{color:var(--ink);font-size:22px;line-height:2;font-weight:700}.zh{color:var(--muted);font-size:13px}.jp-chunk{display:inline-block;white-space:nowrap;max-width:100%;font-size:inherit!important;line-height:inherit!important;font-family:inherit!important}.a{color:var(--green)!important}.b{color:var(--rose)!important}.c{color:var(--blue)!important}
.list-rows,.steps,.summary-rows{border-top:2px solid var(--ink)}.list-row,.steps>div,.summary-rows>div{display:grid;grid-template-columns:48px 190px minmax(0,1fr);gap:18px;align-items:baseline;padding:19px 0;border-bottom:1px solid var(--line)}.list-row>span,.steps>div>span,.summary-rows>div>span{color:var(--faint);font:400 13px/1 Georgia,serif}.list-row h3,.steps strong,.summary-rows strong{margin:0;font-size:17px}.list-row p,.steps p,.summary-rows p{margin:0!important;color:var(--muted)!important;font-size:13px!important;line-height:1.8!important}
.practice{width:min(820px,100%);margin:38px auto 0;padding-top:24px;border-top:1px solid var(--line)}.practice-label{margin:0;color:var(--accent);font-size:9px;font-weight:900;letter-spacing:.13em}.practice h3{margin:6px 0 5px;font-size:24px}.practice-lead{margin:0!important;color:var(--muted)!important;font-size:13px!important}.question{margin-top:18px;padding:18px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}.question .jp{margin:0!important}.question .zh{margin:3px 0 0!important}.options{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-top:16px}.options button{min-height:46px;border:1px solid var(--line2);background:transparent;color:var(--ink);cursor:pointer}.options button.correct{border-color:#5c8b72;background:color-mix(in srgb,#5c8b72 10%,transparent)}.options button.wrong{border-color:#9b665f;background:color-mix(in srgb,#9b665f 9%,transparent)}.feedback{margin-top:12px;font-size:13px;font-weight:800}.answer{margin-top:13px;padding-top:13px;border-top:1px solid var(--line);color:var(--muted);font-size:13px}.answer p{margin:5px 0 0}.related{width:min(820px,100%);margin:54px auto 90px}.related h2{font-size:21px;margin:0 0 6px}.related>p{margin:0 0 12px;color:var(--muted);font-size:13px}.related a{display:flex;justify-content:space-between;gap:20px;padding:13px 0;border-top:1px solid var(--line);text-decoration:none}.related a:last-child{border-bottom:1px solid var(--line)}.related a span:last-child{color:var(--muted);font-size:11px}
@media(max-width:900px){.hero-grid{grid-template-columns:1fr;gap:18px}.hero-note{max-width:650px}.list-row,.steps>div,.summary-rows>div{grid-template-columns:42px 160px minmax(0,1fr)}}
@media(max-width:650px){.page{width:100%}.nav-inner{width:calc(100% - 24px);grid-template-columns:1fr auto}.brand small,.current-topic{display:none}.hero{padding:38px 18px 30px}.hero h1{font-size:clamp(35px,11vw,48px)}.meaning{font-size:17px}.reading-nav{top:68px;padding:0 18px}.reading-nav-inner{gap:17px}.section{padding:52px 18px}.section h2{font-size:29px}.list-row,.steps>div,.summary-rows>div{grid-template-columns:34px minmax(0,1fr);gap:6px 10px}.list-row h3,.steps strong,.summary-rows strong{grid-column:2}.list-row p,.steps p,.summary-rows p{grid-column:2}.options{grid-template-columns:1fr}.related{padding:0 18px;margin-bottom:70px}.jp{font-size:20px}}


.reason-paths{display:grid;grid-template-columns:1fr 70px 1fr;gap:0}.reason-path{padding:24px 26px;border-top:2px solid var(--ink);border-bottom:1px solid var(--line)}.reason-path span{color:var(--faint);font-size:9px;font-weight:900}.reason-path h3{margin:7px 0 8px;font-size:24px}.reason-path p{margin:0;color:var(--muted);font-size:14px}.reason-path .jp{margin-top:18px;color:var(--ink)}.reason-vs{display:grid;place-items:center;color:var(--faint);font-size:10px;font-weight:900}.overlap{border-top:2px solid var(--ink)}.overlap-row{display:grid;grid-template-columns:220px minmax(0,1fr);gap:28px;padding:22px 0;border-bottom:1px solid var(--line)}.overlap-row>strong{font-size:18px}.overlap-row p{margin:0;color:var(--muted);font-size:13px}.tone-scale{border-top:2px solid var(--ink)}.tone-item{display:grid;grid-template-columns:180px minmax(0,1fr);gap:28px;padding:20px 0;border-bottom:1px solid var(--line)}.tone-item h3{margin:0;font-size:18px}.tone-item .jp{margin:0}.tone-item p:last-child{margin:4px 0 0;color:var(--muted);font-size:13px}.form-lines{border-top:2px solid var(--ink)}.form-lines div{display:grid;grid-template-columns:250px minmax(0,1fr);gap:24px;padding:17px 0;border-bottom:1px solid var(--line)}.form-lines p{margin:0;color:var(--muted);font-size:13px}@media(max-width:700px){.reason-paths{grid-template-columns:1fr}.reason-vs{height:34px}.overlap-row,.tone-item,.form-lines div{grid-template-columns:1fr;gap:6px}}