/* Apple design tokens — :root paste sourced from design-systems/apple/tokens.css. Declaration values are verbatim; long prose comments are condensed and CJK fallbacks are appended to the font stacks for localized rendering. */
:root{
color-scheme:light dark;
--bg:#ffffff;
--surface:#f5f5f7;
--surface-warm:#fbfbfd;
--fg:#1d1d1f;
--fg-2:#424245;
--muted:#6e6e73;
--meta:#86868b;
--border:#d2d2d7;
--border-soft:#e8e8ed;
--accent:#0071e3;
--accent-on:#ffffff;
--accent-hover:#0077ed;
--accent-active:#0066cc;
--success:#16a34a;
--warn:#eab308;
--danger:#dc2626;
--font-display:"SF Pro Display","SF Pro Icons","Helvetica Neue",Helvetica,Arial,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
--font-body:"SF Pro Text","SF Pro Icons","Helvetica Neue",Helvetica,Arial,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
--font-mono:"SF Mono",ui-monospace,"JetBrains Mono",Menlo,Monaco,Consolas,monospace;
--text-xs:12px;
--text-sm:14px;
--text-base:17px;
--text-lg:21px;
--text-xl:28px;
--text-2xl:40px;
--text-3xl:56px;
--text-4xl:80px;
--leading-body:1.47;
--leading-tight:1.05;
--tracking-display:-0.015em;
--space-1:4px;
--space-2:8px;
--space-3:12px;
--space-4:16px;
--space-5:20px;
--space-6:24px;
--space-8:32px;
--space-12:48px;
--section-y-desktop:100px;
--section-y-tablet:64px;
--section-y-phone:40px;
--radius-sm:8px;
--radius-md:12px;
--radius-lg:18px;
--radius-pill:980px;
--elev-flat:none;
--elev-ring:0 0 0 1px var(--border);
--elev-raised:0 12px 32px rgba(0,0,0,0.08);
--focus-ring:0 0 0 4px color-mix(in oklab, var(--accent), transparent 65%);
--motion-fast:150ms;
--motion-base:220ms;
--ease-standard:cubic-bezier(0.28,0,0.22,1);
--container-max:1024px;
--container-gutter-desktop:22px;
--container-gutter-tablet:18px;
--container-gutter-phone:16px;
}
@media (prefers-color-scheme:dark){
:root{
--bg:#000000;
--surface:#161617;
--surface-warm:#1d1d1f;
--fg:#f5f5f7;
--fg-2:#e8e8ed;
--muted:#a1a1a6;
--meta:#86868b;
--border:#424245;
--border-soft:#2d2d2f;
--accent:#2997ff;
--accent-on:#ffffff;
--accent-hover:#53a9ff;
--accent-active:#0066cc;
--success:#30d158;
--warn:#ffd60a;
--danger:#ff453a;
--elev-raised:0 12px 32px rgba(0,0,0,0.45);
--focus-ring:0 0 0 4px color-mix(in oklab, var(--accent), transparent 60%);
}
}
/* Base */
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:72px}
body{margin:0;background:var(--bg);color:var(--fg);font-family:var(--font-body);font-size:var(--text-base);line-height:var(--leading-body);letter-spacing:-0.022em;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
h1,h2,h3,p,dl,dd,ol,ul,figure{margin:0}
ol,ul{padding:0}
button,input{font:inherit;color:inherit}
img{max-width:100%}
:focus-visible{outline:none;box-shadow:var(--focus-ring)}
::selection{background:color-mix(in oklab, var(--accent), transparent 80%)}
a{color:var(--accent-active);text-decoration:none}
a:hover{text-decoration:underline}
.container{max-width:var(--container-max);margin-inline:auto;padding-inline:var(--container-gutter-desktop)}
/* Global nav */
.globalnav{position:sticky;top:0;z-index:50;background:color-mix(in srgb, var(--bg) 72%, transparent);-webkit-backdrop-filter:saturate(180%) blur(20px);backdrop-filter:saturate(180%) blur(20px);border-bottom:1px solid var(--border-soft)}
.nav-inner{max-width:var(--container-max);margin-inline:auto;padding-inline:var(--container-gutter-desktop);height:52px;display:flex;align-items:center;gap:20px}
.brand{font-family:var(--font-display);font-weight:600;font-size:15px;letter-spacing:-0.01em;color:var(--fg);white-space:nowrap}
.brand small{font-family:var(--font-body);font-weight:400;color:var(--muted);font-size:12px;margin-left:8px;letter-spacing:0}
.nav-links{display:flex;gap:20px;margin-left:8px}
.nav-links a{font-size:12px;color:var(--fg-2)}
.nav-links a:hover{color:var(--fg);text-decoration:none}
.lang-seg{margin-left:auto;display:inline-flex;background:var(--surface);border:1px solid var(--border-soft);border-radius:var(--radius-pill);padding:2px;gap:2px;flex:none}
.lang-seg button{border:0;background:transparent;border-radius:var(--radius-pill);padding:5px 12px;font-size:12px;font-weight:500;color:var(--muted);cursor:pointer;transition:all var(--motion-fast) var(--ease-standard)}
.lang-seg button:hover{color:var(--fg)}
.lang-seg button[aria-pressed="true"]{background:var(--bg);color:var(--fg);box-shadow:0 1px 4px rgba(0,0,0,0.14)}
/* Hero — showcase chapter. Light mode stays light like the rest of the page (accent blue links, faint hairline); dark mode keeps the original black showcase look. */
:root{
--hero:#f5f5f7;
--hero-fg:var(--fg);
--hero-muted:var(--muted);
--hero-line:rgba(0,0,0,0.12);
--link-dark:var(--accent);
--hero-btn-hover:rgba(0,0,0,0.06);
}
@media (prefers-color-scheme:dark){
:root{
--hero:#000000;
--hero-fg:#f5f5f7;
--hero-muted:#a1a1a6;
--hero-line:rgba(255,255,255,0.16);
--link-dark:#2997ff;
--hero-btn-hover:rgba(255,255,255,0.08);
}
}
.hero{background:var(--hero);color:var(--hero-fg);text-align:center;padding:96px 22px 84px;position:relative;overflow:hidden}
.hero::after{content:"";position:absolute;left:50%;top:-240px;width:680px;height:460px;transform:translateX(-50%);background:radial-gradient(closest-side,color-mix(in srgb, var(--link-dark) 26%, transparent),transparent);pointer-events:none}
.hero>*{position:relative}
.hero h1{font-family:var(--font-display);font-size:clamp(40px,6vw,64px);font-weight:600;letter-spacing:var(--tracking-display);line-height:1.04;text-wrap:balance}
.hero .sub{margin:16px auto 0;max-width:660px;font-size:19px;line-height:1.42;color:var(--hero-muted)}

.hero-cta{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;margin-top:30px}
.btn-pill{display:inline-flex;align-items:center;gap:8px;padding:12px 26px;border-radius:var(--radius-pill);font-size:var(--text-base);cursor:pointer;border:0;background:var(--accent);color:var(--accent-on);transition:background-color var(--motion-fast) var(--ease-standard),transform var(--motion-fast) var(--ease-standard),box-shadow var(--motion-fast) var(--ease-standard)}
.btn-pill:hover{background:var(--accent-hover)}
.btn-pill:active{background:var(--accent-active);transform:scale(0.98)}
.btn-pill.ghost{background:transparent;color:var(--link-dark);box-shadow:inset 0 0 0 1px var(--hero-line)}
.btn-pill.ghost:hover{background:var(--hero-btn-hover)}
.hero-stats{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;max-width:720px;margin:56px auto 0;padding-top:28px;border-top:1px solid var(--hero-line)}
.hero-stats small{display:block;font-size:12px;color:var(--hero-muted);margin-bottom:6px}
.hero-stats b{font-family:var(--font-display);font-size:clamp(20px,3vw,28px);font-weight:600;font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
/* Commerce buttons */
.btn{display:inline-flex;align-items:center;gap:8px;padding:8px 16px;border:1px solid var(--border);border-radius:var(--radius-sm);background:var(--bg);color:var(--fg);font-size:var(--text-sm);font-weight:500;cursor:pointer;transition:all var(--motion-fast) var(--ease-standard)}
.btn:hover{border-color:var(--meta);background:var(--surface-warm)}
.btn:active{transform:scale(0.98)}
.btn.primary{background:var(--accent);border-color:var(--accent);color:var(--accent-on)}
.btn.primary:hover{background:var(--accent-hover);border-color:var(--accent-hover)}
.btn.primary:active{background:var(--accent-active)}
.mini{border:1px solid var(--border);background:var(--bg);border-radius:var(--radius-sm);padding:3px 12px;font-size:12px;cursor:pointer;color:var(--fg)}
.mini:hover{border-color:var(--accent);color:var(--accent)}
/* Sections, panels, cards */
.page{padding:48px 0 0}
.sec-head{padding:32px 32px 10px}
.sec-head h2{font-family:var(--font-display);font-size:24px;font-weight:600;letter-spacing:var(--tracking-display)}
.sec-head p{margin-top:6px;font-size:14px;color:var(--muted)}
.panel{background:var(--bg);border:1px solid var(--border);border-radius:var(--radius-lg);margin-bottom:24px;overflow:hidden}
.band{background:var(--surface);border-block:1px solid var(--border-soft);padding:64px 0;margin:48px 0}
.band-grid{display:grid;grid-template-columns:1.12fr 0.88fr;gap:24px;align-items:start}
.card{background:var(--bg);border:1px solid var(--border);border-radius:var(--radius-lg);padding:28px;min-width:0}
.card h2{font-family:var(--font-display);font-size:21px;font-weight:600;letter-spacing:var(--tracking-display)}
.card .sub{font-size:14px;color:var(--muted);margin-top:4px}
/* Configurator rows */
.thead,.frow,.totalrow{display:grid;grid-template-columns:minmax(0,1.5fr) 150px repeat(4,minmax(0,1fr));gap:12px;align-items:center}
.thead{font-size:12px;color:var(--meta);letter-spacing:0.04em;border-block:1px solid var(--border-soft);background:var(--surface-warm);padding:12px 32px}
.thead span:nth-child(n+3){text-align:right}
.fgroup{padding:18px 32px 2px;font-size:12px;font-weight:600;letter-spacing:0.08em;text-transform:uppercase;color:var(--accent)}
.frow{border-bottom:1px solid var(--border-soft);padding:16px 32px}
.fname{min-width:0}
.fname b{display:block;font-size:15px;font-weight:600}
.fname span{display:block;font-size:13px;color:var(--muted);margin-top:2px}
.tag{display:inline-block;margin-left:8px;padding:1px 8px;border-radius:var(--radius-pill);background:var(--surface);border:1px solid var(--border-soft);color:var(--muted);font-size:11px;font-weight:600;vertical-align:2px}
.num{text-align:right;font-family:var(--font-mono);font-size:14px;font-variant-numeric:tabular-nums;min-width:0;overflow-wrap:anywhere}
.num::before{content:attr(data-label);display:none}
.pos{color:var(--success)}
.neg{color:var(--danger)}
.dim{color:var(--meta)}
.totalrow{padding:16px 32px;background:var(--surface);border-top:1px solid var(--border);font-weight:600}
.stepper{display:inline-flex;align-items:center;border:1px solid var(--border);border-radius:var(--radius-pill);padding:3px;background:var(--surface-warm)}
.stepper button{width:28px;height:28px;border-radius:50%;border:0;background:var(--bg);box-shadow:0 0 0 1px var(--border-soft);color:var(--accent);font-size:16px;line-height:1;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;padding:0}
.stepper button:hover{box-shadow:0 0 0 1px var(--accent)}
.stepper input{width:46px;border:0;background:transparent;text-align:center;font-family:var(--font-mono);font-weight:600;font-size:15px;padding:4px 0;min-width:0}
.stepper input:focus-visible{box-shadow:none}
/* Summary card */
.big{font-family:var(--font-display);font-size:44px;font-weight:600;letter-spacing:var(--tracking-display);font-variant-numeric:tabular-nums;overflow-wrap:anywhere;margin-top:6px}
.big.pos{color:var(--success)}
.big.neg{color:var(--danger)}
.roi-line{margin-top:2px;font-size:14px;color:var(--muted)}
.roi-line b{color:var(--fg);font-family:var(--font-mono);font-weight:600}
.meter-top{display:flex;justify-content:space-between;gap:8px;font-size:13px;color:var(--muted);margin-top:20px}
.meter-top b{color:var(--fg);font-family:var(--font-mono);font-size:13px;font-weight:500}
.meter{height:8px;border-radius:var(--radius-pill);background:var(--surface);box-shadow:inset 0 0 0 1px var(--border-soft);overflow:hidden;margin-top:8px}
.meter i{display:block;height:100%;background:var(--accent);border-radius:var(--radius-pill);transition:width var(--motion-base) var(--ease-standard)}
.meter.over i{background:var(--danger)}
.kv{margin:20px 0 0;display:grid;grid-template-columns:1fr auto;gap:9px 12px;font-size:14px}
.kv dt{color:var(--muted)}
.kv dd{margin:0;text-align:right;font-family:var(--font-mono);font-weight:500;font-size:13.5px;font-variant-numeric:tabular-nums}
.rules-line{display:flex;justify-content:space-between;align-items:center;margin-top:20px;padding-top:16px;border-top:1px solid var(--border-soft);font-size:14px}
.pill{padding:2px 12px;border-radius:var(--radius-pill);font-size:12px;font-weight:700;white-space:nowrap}
.pill.ok{background:color-mix(in srgb, var(--success) 14%, transparent);color:var(--success)}
.pill.no{background:color-mix(in srgb, var(--danger) 10%, transparent);color:var(--danger)}
.checks{display:grid;gap:10px;margin-top:16px}
.check{border:1px solid var(--border);border-radius:var(--radius-md);padding:12px 14px}
.check .t{display:flex;justify-content:space-between;align-items:center;gap:8px;font-size:14px;font-weight:600}
.check .d{font-family:var(--font-mono);font-size:12.5px;color:var(--muted);margin-top:4px;overflow-wrap:anywhere}
.note{font-size:12.5px;color:var(--muted);margin-top:14px;line-height:1.6}
/* Chart */
.chart-box{padding:8px 28px 28px}
#chart{width:100%;min-height:280px}
#chart svg{display:block;width:100%;height:auto}
.ax{fill:var(--meta);font-family:var(--font-mono);font-size:12px}
.axb{fill:var(--fg);font-family:var(--font-mono);font-size:12px;font-weight:600}
.grid{stroke:var(--border-soft);stroke-width:1}
.zero{stroke:var(--meta);stroke-width:1.2}
.line{stroke:var(--accent);stroke-width:2.5;fill:none;stroke-linejoin:round;stroke-linecap:round}
.dot{fill:var(--accent);stroke:var(--bg);stroke-width:2}
.dot.pb{fill:var(--success)}
.dot.yr{opacity:.65}
.chart-box{position:relative}
.chart-tip{position:absolute;z-index:5;pointer-events:none;background:color-mix(in srgb, var(--fg) 92%, transparent);color:var(--bg);border-radius:10px;padding:8px 12px;font-size:12px;line-height:1.55;box-shadow:var(--elev-raised);white-space:nowrap;transform:translate(-50%,calc(-100% - 16px));min-width:120px}
.chart-tip.below{transform:translate(-50%,16px)}
.chart-tip b{display:block;font-size:13px;margin-bottom:2px}
.chart-tip span{display:block;font-family:var(--font-mono);font-variant-numeric:tabular-nums;opacity:.94}
.chart-tip::after{content:"";position:absolute;left:50%;bottom:-4px;width:8px;height:8px;transform:translateX(-50%) rotate(45deg);background:inherit}
.chart-tip.below::after{bottom:auto;top:-4px}
#chart-vline{stroke:var(--accent);stroke-width:1;stroke-dasharray:4 4;opacity:.7}
#chart-hdot{fill:var(--accent);stroke:var(--bg);stroke-width:2}
.empty{padding:48px 16px;text-align:center;color:var(--muted);font-size:14px}
/* Process */
.psec{padding:4px 32px 32px}
.steps{list-style:none;counter-reset:s;display:flex;flex-direction:column}
.step{counter-increment:s;display:grid;grid-template-columns:28px minmax(0,1fr) auto;gap:2px 12px;padding:13px 0;border-bottom:1px solid var(--border-soft)}
.step::before{content:counter(s);grid-row:1/3;width:24px;height:24px;border-radius:50%;background:color-mix(in srgb, var(--accent) 12%, transparent);color:var(--accent);font-size:12px;font-weight:600;line-height:24px;text-align:center}
.step .st{font-weight:600;font-size:15px}
.step .sr{grid-column:3;grid-row:1;font-family:var(--font-mono);font-weight:600;font-size:14px;text-align:right;font-variant-numeric:tabular-nums}
.step .sf{grid-column:2;font-size:12.5px;color:var(--muted)}
.step .sc{grid-column:2/4;font-family:var(--font-mono);font-size:12.5px;overflow-wrap:anywhere}
.sub-h{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap;margin:26px 0 10px}
.sub-h h3{font-family:var(--font-display);font-size:16px;font-weight:600}
.btns{display:flex;gap:8px}
.scroll{overflow-x:auto}
table.tbl{width:100%;border-collapse:collapse;min-width:520px;font-size:14px}
.tbl th,.tbl td{padding:9px 12px;border-bottom:1px solid var(--border-soft);text-align:right;white-space:nowrap}
.tbl th:first-child,.tbl td:first-child{text-align:left}
.tbl th{font-size:12px;color:var(--muted);font-weight:500;background:var(--surface-warm)}
.tbl td{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.tbl td:first-child{font-family:var(--font-body);font-weight:500}
.tbl tr.sum td{font-weight:700;background:var(--surface-warm)}
details.fac{border:1px solid var(--border);border-radius:var(--radius-md);margin-bottom:8px;background:var(--bg)}
details.fac>summary{list-style:none;cursor:pointer;display:flex;gap:14px;align-items:baseline;padding:12px 16px;flex-wrap:wrap}
details.fac>summary::-webkit-details-marker{display:none}
details.fac>summary::marker{content:""}
details.fac>summary::before{content:"›";color:var(--accent);font-size:16px;transition:transform var(--motion-fast) var(--ease-standard)}
details.fac[open]>summary::before{transform:rotate(90deg)}
.fn{font-weight:600;margin-right:auto;font-size:14px}
.fs{font-family:var(--font-mono);font-size:13px}
.calc{display:grid;grid-template-columns:auto minmax(0,1fr) auto;gap:7px 14px;padding:14px 16px 16px;border-top:1px dashed var(--border);font-size:13px}
.calc .l{color:var(--muted)}
.calc .f{font-family:var(--font-mono);font-size:12.5px;overflow-wrap:anywhere}
.calc .r{font-family:var(--font-mono);font-weight:500;font-size:13px;text-align:right;font-variant-numeric:tabular-nums}
/* Params */
details.params summary{list-style:none;cursor:pointer;padding:24px 32px;display:flex;gap:6px 16px;align-items:baseline;flex-wrap:wrap}
details.params summary::-webkit-details-marker{display:none}
details.params summary::marker{content:""}
.sum-title{font-family:var(--font-display);font-size:20px;font-weight:600;letter-spacing:var(--tracking-display)}
.sum-sub{font-size:14px;color:var(--muted)}
.hint{margin-left:auto;color:var(--accent);font-size:14px;white-space:nowrap}
.pbody{padding:0 32px 28px;display:flex;flex-direction:column;gap:18px}
.prow{display:grid;grid-template-columns:minmax(150px,1.4fr) repeat(4,minmax(90px,1fr));gap:10px;align-items:center;padding:7px 0;border-bottom:1px solid var(--border-soft)}
.prow.h{font-size:12px;color:var(--muted)}
.prow.h span:nth-child(n+2){text-align:right}
.pn{font-size:14px;font-weight:500}
input.field{width:100%;border:1px solid var(--border);background:var(--bg);border-radius:var(--radius-sm);padding:8px 10px;text-align:right;font-family:var(--font-mono);font-size:14px;min-width:0}
input.field:hover{border-color:var(--meta)}
input.field:focus-visible{outline:none;border-color:var(--accent);box-shadow:var(--focus-ring)}
.gl{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:12px}
.gl label{display:flex;flex-direction:column;gap:6px;font-size:12.5px;color:var(--muted)}
.ro{border:1px dashed var(--border);border-radius:var(--radius-sm);padding:8px 10px;text-align:right;font-family:var(--font-mono);font-size:14px;color:var(--fg)}
/* Mobile bar, toast */
main{padding-bottom:64px}
.bar{display:none}
.toast{position:fixed;left:50%;bottom:28px;transform:translateX(-50%);background:var(--fg);color:var(--bg);padding:10px 22px;border-radius:var(--radius-pill);font-size:14px;z-index:60;opacity:0;pointer-events:none;transition:opacity var(--motion-base) var(--ease-standard);white-space:nowrap;max-width:calc(100vw - 32px);overflow:hidden;text-overflow:ellipsis}
.toast.on{opacity:1}
@media (max-width:900px){
.band-grid{grid-template-columns:minmax(0,1fr)}
.nav-links{display:none}
}
@media (max-width:680px){
.hero{padding:72px 18px 64px}
.hero .sub{font-size:17px}
.thead{display:none}
.frow,.totalrow{grid-template-columns:minmax(0,1fr) auto}
.frow{grid-template-areas:"name step" "a b" "c d";row-gap:12px}
.frow .fname{grid-area:name}
.frow .stp{grid-area:step}
.frow .num:nth-child(3){grid-area:a}
.frow .num:nth-child(4){grid-area:b}
.frow .num:nth-child(5){grid-area:c}
.frow .num:nth-child(6){grid-area:d}
.frow .num{text-align:left;display:flex;flex-direction:column;gap:2px}
.num::before{display:block;font-family:var(--font-body);font-size:11.5px;color:var(--muted)}
.totalrow{row-gap:8px}
.totalrow .num{text-align:right}
.sec-head,.psec{padding-inline:20px}
.thead,.frow{padding-inline:20px}
.totalrow{padding-inline:20px}
.card{padding:22px 20px}
details.params summary{padding:20px}
.pbody{padding:0 20px 22px}
.chart-box{padding:4px 12px 20px}
.page{padding-top:32px}
.band{padding:40px 0;margin:32px 0}
.bar{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;position:fixed;left:0;right:0;bottom:0;z-index:40;padding:10px 16px calc(10px + env(safe-area-inset-bottom,0px));background:color-mix(in srgb, var(--bg) 78%, transparent);-webkit-backdrop-filter:saturate(180%) blur(20px);backdrop-filter:saturate(180%) blur(20px);border-top:1px solid var(--border-soft)}
.bar small{display:block;font-size:11px;color:var(--muted)}
.bar b{font-family:var(--font-mono);font-size:14px;font-weight:600;overflow-wrap:anywhere}
.toast{bottom:88px}
main{padding-bottom:120px}
.calc{grid-template-columns:minmax(0,1fr) auto}
.calc .f{grid-column:1/3;grid-row:2}
.calc .l{grid-row:1}
.calc .r{grid-row:1;grid-column:2}
}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}