:root{color-scheme:light;--paper:#f7f7f2;--white:#fff;--ink:#233d34;--muted:#68716b;--line:#dce1d8;--green:#28624d;--green-light:#e8efe6;--amber:#9b591c;--amber-light:#f6edde;--mono:ui-monospace,SFMono-Regular,Consolas,monospace;font-family:Arial,Helvetica,sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none;-webkit-font-smoothing:antialiased}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0}a{color:inherit;text-underline-offset:4px}button,input{font:inherit}button{cursor:pointer}button:disabled{cursor:default;opacity:.35}button,a,input,summary{touch-action:manipulation}button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible,[tabindex]:focus-visible{outline:3px solid #397cba;outline-offset:4px}button{color:inherit}p,h1,h2,h3{margin:0}p{line-height:1.65}[hidden]{display:none!important}.skip-link{position:absolute;left:20px;top:-100px;background:white;padding:14px;z-index:10}.skip-link:focus{top:10px}.site-nav,main,footer{max-width:1280px;margin:auto;padding-left:40px;padding-right:40px}.site-nav{min-height:88px;display:flex;align-items:center;justify-content:space-between;gap:20px;font-size:12px;border-bottom:1px solid var(--line)}.site-nav a{text-decoration:none}.wordmark{font-weight:600}.wordmark>span:first-child{padding:0 15px;color:#abb3a9}.wordmark>span:last-child{font-weight:400;color:var(--muted)}.site-nav>div{display:flex;gap:28px}.site-nav a:hover,footer a:hover{color:var(--green);text-decoration:underline}.hero{display:grid;grid-template-columns:1.2fr 1fr;align-items:end;gap:80px;padding:65px 0 54px}.eyebrow{text-transform:uppercase;font-size:10px;letter-spacing:1.7px;line-height:1.5;font-weight:600}.hero .eyebrow{display:flex;align-items:center;gap:9px;margin-bottom:22px}.small-cross{font-size:22px;line-height:1;color:var(--green)}h1{font-family:Georgia,'Times New Roman',serif;font-size:clamp(44px,5.5vw,72px);font-weight:400;letter-spacing:-3px;line-height:1.02}em{font-weight:400;color:var(--green)}.hero-intro{max-width:405px;padding-bottom:3px}.hero-intro>p:first-child{font-size:18px;line-height:1.5;margin-bottom:13px;letter-spacing:-.2px}.hero-intro>p:nth-child(2){font-size:14px;color:var(--muted)}.hero-intro>a{display:inline-flex;gap:30px;text-decoration:none;font-size:12px;font-weight:600;margin-top:22px}.section-line{display:flex;align-items:baseline;justify-content:space-between;gap:16px;padding-bottom:15px}.section-line h2,.section-line h3{font-size:12px;font-weight:500}.section-line>span{font:10px var(--mono);color:var(--muted)}.problem-nav{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));border:1px solid var(--line);border-radius:4px;overflow:hidden}.problem-button{background:transparent;border:0;border-right:1px solid var(--line);padding:17px 15px 13px;text-align:left;min-width:0;position:relative}.problem-button:last-child{border-right:0}.problem-button:hover{background:#edf1e9}.problem-button[aria-pressed=true]{background:var(--ink);color:white}.problem-button .number{font:9px var(--mono);opacity:.6;display:block;margin-bottom:16px}.problem-button .name{font-size:12px;line-height:1.4;display:block;min-height:34px}.problem-button .mini-value{font:11px var(--mono);display:block;margin-top:13px}.problem-button svg{width:100%;height:30px;margin-top:10px;display:block}.collection{margin-bottom:40px}.explorer{border:1px solid var(--line);border-radius:5px;background:var(--white);overflow:hidden}.explorer-heading{display:flex;align-items:center;justify-content:space-between;padding:24px 28px;gap:20px;border-bottom:1px solid var(--line)}.explorer-heading 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.target-line{stroke:#91aa92;stroke-dasharray:4 5}.chart .data-line{stroke:var(--green);stroke-width:2.5;fill:none;stroke-linejoin:round}.chart .reported-line{stroke:var(--amber);stroke-dasharray:5 4}.chart .point{cursor:pointer;stroke-width:2.5;fill:white;stroke:var(--green)}.chart .point.selected{fill:var(--green)}.chart .point.report{stroke:var(--amber)}.chart .point.report.selected{fill:var(--amber)}.chart .point.ai{stroke:#7755a0;stroke-width:4}.chart .hit-area{fill:transparent;cursor:pointer}.chart-legend{display:flex;gap:15px;flex-wrap:wrap;font-size:9px;color:var(--muted);min-height:14px}.legend-item{display:flex;align-items:center;gap:5px}.legend-line{width:14px;border-top:2px solid var(--green)}.legend-line.report{border-color:var(--amber);border-top-style:dashed}.legend-line.target{border-color:#91aa92;border-top-style:dashed}.legend-line.lower{border-color:#758dba}.chart-note{font-size:10px;color:var(--muted);margin:12px 0 20px;min-height:32px}.timeline-controls{display:flex;align-items:center;gap:10px;border-top:1px solid var(--line);padding-top:18px}.timeline-controls button{border:1px solid var(--line);background:var(--white);border-radius:3px;height:35px}.timeline-controls .play{background:var(--ink);color:white;border-color:var(--ink);font-size:10px;padding:0 10px;white-space:nowrap}.step{width:30px;flex-shrink:0}.scrubber{flex:1;min-width:0;padding:0 4px}.scrubber label{display:flex;justify-content:space-between;font:9px var(--mono);color:var(--muted);margin-bottom:5px}.scrubber input{width:100%;height:12px;margin:0;accent-color:var(--green)}.story-column{background:#fafbf7;border-left:1px solid var(--line);padding:28px 25px}.story-column>.eyebrow{font-size:9px;color:var(--muted);margin-bottom:12px}.story-column 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table{border-collapse:collapse;min-width:600px;width:100%;font-size:11px;text-align:left}.sources th{font-size:10px;color:var(--muted);font-weight:500}.sources td,.sources th{padding:12px 14px 12px 0;border-bottom:1px solid var(--line);vertical-align:top;line-height:1.7}.sources td:last-child{max-width:380px}.sources .table-note{display:block;color:var(--muted);font-size:10px}.grid-intro{font-size:10px;color:var(--muted);padding:12px 0}.order-grid{display:grid;grid-template-columns:repeat(25,minmax(0,1fr));gap:3px;padding:10px 0 16px}.order-cell{aspect-ratio:1;background:#bdd1b3;border-radius:1px}.order-cell.unknown{background:#f4e0c4;outline:1px solid #bf864f}.order-cell.resolved{background:repeating-linear-gradient(45deg,#e6c99d,#e6c99d 3px,#fbf0df 3px,#fbf0df 6px);outline:1px solid #bf864f}.grid-cases{display:flex;flex-wrap:wrap;gap:5px;margin-bottom:14px}.grid-cases button{background:var(--amber-light);border:1px solid #e4d0b4;border-radius:3px;font:10px var(--mono);padding:6px}.grid-cases button[aria-pressed=true]{background:var(--amber);color:white}.grid-detail{font-size:11px;min-height:36px;color:var(--muted);padding-bottom:10px}.no-js{border:1px solid var(--line);padding:20px;margin:20px 0}footer{border-top:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:20px;padding-top:25px;padding-bottom:35px;font-size:11px}footer a{text-decoration:none}footer p{font-family:Georgia,serif;font-style:italic;font-size:16px;color:var(--muted)}
@media(min-width:1400px){.hero{padding-top:75px;padding-bottom:65px}}@media(max-width:1000px){.site-nav,main,footer{padding-left:25px;padding-right:25px}.hero{gap:40px}.problem-nav{grid-template-columns:repeat(3,minmax(0,1fr))}.problem-button:nth-child(3){border-right:0}.problem-button:nth-child(-n+3){border-bottom:1px solid var(--line)}.problem-button .number{margin-bottom:9px}.problem-button .name{min-height:0}.problem-button svg{position:absolute;right:14px;bottom:15px;width:50px;height:22px}.explorer-body{grid-template-columns:minmax(0,1.7fr) minmax(230px,1fr)}.plot-column{padding:22px 20px}.story-column{padding:25px 20px}.reading-guide{gap:40px}.chart{min-height:200px}}
@media(max-width:700px){.site-nav,main,footer{padding-left:18px;padding-right:18px}.site-nav{min-height:66px;font-size:11px}.wordmark>span{display:none}.site-nav>div{gap:15px}.hero{grid-template-columns:1fr;gap:25px;padding:38px 0 32px}h1{font-size:clamp(42px,13.8vw,54px);letter-spacing:-2.5px}.hero .eyebrow{font-size:9px;margin-bottom:17px}.hero-intro{max-width:500px}.hero-intro>p:first-child{font-size:17px}.hero-intro>p:nth-child(2){font-size:13px}.hero-intro>a{margin-top:15px}.problem-button{padding:13px 10px}.problem-button .name{font-size:11px;min-height:30px}.problem-button .mini-value{font-size:10px;margin-top:8px}.problem-button svg{position:static;width:100%;height:24px;margin-top:8px}.problem-button .number{font-size:8px}.section-line>span{font-size:9px}.collection{margin-bottom:25px}.explorer-heading{padding:20px 18px;align-items:flex-start;flex-direction:column;gap:17px}.explorer-heading h2{font-size:27px}.explorer-options{flex-direction:row;flex-wrap:wrap;gap:14px;font-size:10px}.explorer-body{grid-template-columns:1fr}.plot-column{padding:18px 14px}.metric-value{font-size:40px}.chart{min-height:0}.chart>svg{min-height:240px}.chart text{font-size:12px}.chart .target-label{font-size:11px}.chart .axis-label{font-size:10px}.chart-note{font-size:11px;margin-bottom:18px}.timeline-controls{gap:6px}.timeline-controls .play{padding:0 9px}.timeline-controls .play span{display:none}.scrubber label{font-size:10px}.story-column{border-left:0;border-top:1px solid var(--line);padding:25px 20px}.story-column h3{font-size:22px}.story-column>p:not(.eyebrow){font-size:13px}.milestone-story p:not(.eyebrow){font-size:12px}.interpretation{padding:18px;font-size:12px}.history-section{padding:22px 18px}.milestone-list{grid-template-columns:repeat(3,minmax(0,1fr))}.milestone-button{padding:11px 8px}.milestone-button strong{font-size:12px}.extra-note{padding:18px;font-size:12px}.reading-guide{grid-template-columns:1fr;gap:30px;padding:45px 0}.reading-guide h2{font-size:32px}.guide-notes p{font-size:13px}.sources .section-line{align-items:flex-start;flex-direction:column}.sources .section-line h2{font-size:25px}.sources-intro{font-size:12px}.order-grid{gap:3px}.grid-intro{font-size:11px}.grid-cases button{min-height:33px}.grid-detail{font-size:12px}footer{flex-wrap:wrap;font-size:11px}footer p{order:3;width:100%;font-size:15px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
.visually-hidden{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap}.nav-evidence{float:right;font:8px Arial,sans-serif;letter-spacing:.1px;opacity:1}.problem-button[aria-pressed=false] .nav-evidence{color:var(--amber)}
/* Header links match the other standalone projects. */
.site-nav .site-home-link{display:inline-flex;align-items:center;gap:12px;min-height:42px;padding:10px 16px;background:#20352e;border:1px solid #20352e;border-radius:5px;color:white;font-weight:600;white-space:nowrap}.site-nav .site-home-link:hover{color:white;background:#324e41;text-decoration:none}.site-nav>div{align-items:center;gap:22px}.updated{font:11px var(--mono);color:var(--muted);margin-top:22px}.order-cell{cursor:help}.order-cell:hover{outline:2px solid var(--ink);position:relative;z-index:1}#chart-tooltip{position:fixed;z-index:100;max-width:min(320px,calc(100vw - 20px));padding:10px 13px;border:1px solid #496252;border-radius:4px;background:#233d34;color:white;box-shadow:0 4px 16px #233d3426;white-space:pre-line;font:12px/1.65 var(--mono);pointer-events:none}svg g[data-tooltip]:focus-visible{outline:2px solid #397cba;outline-offset:3px}
@media(max-width:850px){.wordmark>span{display:none}}@media(max-width:700px){.site-nav{flex-wrap:wrap;gap:8px;padding-top:12px;padding-bottom:12px}.site-nav>div{gap:12px;margin-left:auto;flex-wrap:wrap}.site-nav .site-home-link{min-height:38px;padding:8px 10px;font-size:10px}.updated{margin-top:16px}.hero-intro{padding-bottom:0}}

/* Two measures of the Riemann hypothesis share one overview card. */
.riemann-metrics{display:flex;flex-direction:column;gap:9px;margin-top:13px;min-height:51px}
.riemann-metrics>span{display:flex;flex-wrap:wrap;align-items:baseline;gap:3px 9px;line-height:1.2}
.riemann-metrics strong{font:11px var(--mono)}
.riemann-metrics small{font:9px Arial,sans-serif;opacity:.75}
.riemann-navigation{padding:20px 28px 16px;border-bottom:1px solid var(--line)}
.view-tabs{display:flex;gap:6px}
.view-tabs button{padding:11px 16px;border:1px solid var(--line);border-radius:3px;background:transparent;font-size:12px;line-height:1.5}
.view-tabs button[aria-selected=true]{background:var(--ink);border-color:var(--ink);color:white}
.riemann-navigation>p{font-size:12px;color:var(--muted);margin-top:12px;max-width:780px}
.region-controls{display:flex;gap:8px;margin-bottom:20px}
.region-controls button{flex:1;min-width:0;padding:12px 8px;border:1px solid var(--line);border-radius:3px;background:white;font:20px Georgia,serif}
.region-controls small{display:block;font:9px Arial,sans-serif;margin-top:6px;color:var(--muted)}
.region-controls button[aria-pressed=true]{border-color:var(--amber);box-shadow:inset 0 2px var(--amber);background:var(--amber-light)}
.region-controls button[data-region=rh][aria-pressed=true]{border-color:#66718e;box-shadow:inset 0 2px #66718e;background:#edf0f6}
.region-filter-note{font-size:11px;color:var(--muted);margin-bottom:15px}
.region-value{font-size:clamp(25px,3vw,37px);letter-spacing:-1px;white-space:nowrap}
.region-diagram{margin-top:10px}
.region-diagram svg{display:block;width:100%;height:auto;overflow:visible}
.region-diagram text{font:11px var(--mono);fill:var(--muted)}
.region-diagram .critical-label{fill:var(--green);font:12px Arial,sans-serif}
.region-diagram .critical-line{stroke:var(--green);stroke-width:2;fill:none}
.region-diagram .rh-line{stroke-width:4}
.region-diagram .region-boundary{stroke:var(--amber);stroke-width:1.5;stroke-dasharray:4 3}
.region-diagram .region-boundary-dot{fill:var(--amber)}
.region-diagram .boundary-label{fill:var(--amber)}
.region-diagram .region-caption{fill:var(--green);font:12px Arial,sans-serif}
.region-swatch{display:inline-block;width:12px;height:12px;border:1px solid #b3c2b4}
.region-swatch.excluded{background:repeating-linear-gradient(135deg,#e8efe6,#e8efe6 3px,#b1c4b4 3px,#b1c4b4 4px)}
.region-swatch.permitted{background:#fcf3e6;border-color:#c59e73}
.region-legend{margin-top:5px;font-size:10px;gap:10px 15px}
.status.conjecture{color:#51617e;background:#edf0f6}
.measure-comparison{display:grid;grid-template-columns:1fr 1fr;gap:30px;padding:22px 28px;background:var(--green-light);border-top:1px solid var(--line)}
.measure-comparison h3{font-size:12px;font-weight:600;margin-bottom:8px}
.measure-comparison p{font-size:12px;color:#4b6052}
.measure-comparison a{display:inline-block;font-size:11px;margin-top:8px}
.sources .source-subtitle{font-size:13px;font-weight:500;margin:10px 0}
.sources .source-comparison-note{font-size:11px;color:var(--muted);margin-bottom:12px}
@media(max-width:700px){.riemann-navigation{padding:18px 14px}.view-tabs button{padding:10px;flex:1;font-size:11px}.riemann-navigation>p{font-size:11px}.riemann-metrics{margin-top:8px;gap:7px}.riemann-metrics strong{font-size:10px}.riemann-metrics small{font-size:8px}.region-value{font-size:30px}.region-controls{gap:6px}.region-controls button{font-size:19px;padding:10px 6px}.region-controls small{font-size:9px}.region-controls~.metric-row{flex-direction:column;align-items:flex-start;gap:12px;margin-bottom:15px}.region-controls~.metric-row .metric-aside{display:flex;align-items:center;gap:10px;max-width:none;text-align:left}.region-controls~.metric-row .metric-aside p{margin-top:0}.measure-comparison{grid-template-columns:1fr;gap:20px;padding:20px 18px}.region-legend{font-size:10px}}

/* Keep the visual emphasis in sync with the tooltip, including keyboard focus. */
.chart .point-halo{fill:none;stroke:var(--ink);stroke-width:2;opacity:0;pointer-events:none}
.chart g.tooltip-active{opacity:1}
.chart g.tooltip-active .point-halo{opacity:.35}
.chart g.tooltip-active .point{r:7;stroke-width:3.5}
.chart g.tooltip-active .point.ai{stroke-width:4.5}
.problem-button g.tooltip-active .mini-point{r:4;stroke:currentColor;stroke-width:1.5}
.order-cell.tooltip-active{outline:2px solid var(--ink);position:relative;z-index:1}
.region-diagram g.tooltip-active .region-boundary{stroke-width:3;stroke-dasharray:none}
.region-diagram g.tooltip-active .region-boundary-dot{r:6}
.region-diagram g.tooltip-active .critical-line{stroke-width:5}