/* Expert Math Tutor — version 2026-10-27 7:40 PM MDT
   Design idea: the normal curve on Michael's business card, in subdued academic colors.
   Ink navy, ivory paper, brass hairlines, oxblood accents; the curve's sigma bands appear as a quiet
   motif. System fonts only, so nothing blocks rendering. */

:root{
  --paper:#fbfaf6; --pad:#f1ede0; --pad-deep:#d8cfb2; --ink:#16284b; --margin:#7a2e2e; --brass:#9b7a3a;
  --graphite:#2b2f38; --muted:#5a6070; --rule:#cdd4e0; --soft:#f4f2ea; --focus:#7a2e2e; --navy-deep:#101c36;
  --serif: "Iowan Old Style","Palatino Linotype",Palatino,"Book Antiqua",Georgia,serif;
  --sans: system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --line:1.8rem;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important;animation:none!important}}
body{margin:0;background:var(--paper);color:var(--graphite);font:1.0625rem/1.7 var(--sans);-webkit-font-smoothing:antialiased}
img,iframe{max-width:100%}
.wrap{width:min(68rem,100% - 2.5rem);margin-inline:auto}
.skip{position:absolute;left:-999px;top:0;background:var(--ink);color:#fff;padding:.6rem 1rem;z-index:20}
.skip:focus{left:.5rem;top:.5rem}
a{color:var(--ink);text-underline-offset:.18em}
a:hover{color:var(--margin)}
:focus-visible{outline:3px solid var(--focus);outline-offset:3px;border-radius:2px}

h1,h2,h3,h4{font-family:var(--serif);color:var(--ink);line-height:1.18;margin:0 0 .65rem;font-weight:600}
h1{font-size:clamp(2.1rem,4.8vw,3.4rem);letter-spacing:-.018em;line-height:1.1}
h2{font-size:clamp(1.55rem,3vw,2.05rem);margin-top:0;letter-spacing:-.01em}
h3{font-size:1.2rem}
.block h2:first-child::before{content:"";display:block;width:2.6rem;height:2px;background:var(--brass);margin-bottom:.9rem}
p{margin:0 0 1rem}
.lede{font-size:1.22rem;line-height:1.6;max-width:42rem;color:#353a46}
.small{font-size:.95rem;color:var(--muted)}
ul.plain{list-style:none;padding:0;margin:0}


/* header */
.top{border-bottom:1px solid var(--rule);background:var(--paper);position:relative}
.top::after{content:"";position:absolute;left:0;right:0;bottom:-1px;height:2px;background:linear-gradient(to right,var(--ink) 0,var(--ink) 4.5rem,transparent 4.5rem)}
.top-in{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:.5rem 1.5rem;padding:.95rem 0}
.brand{display:flex;align-items:center;gap:.7rem;text-decoration:none;color:var(--ink)}
.brand-mark{display:block;width:2.9rem;height:2.1rem;font-size:0;line-height:0;color:transparent;background:url(../img/bell-mark.svg) center/contain no-repeat}
.brand-name{font:600 1.3rem/1 var(--serif);letter-spacing:.01em}
.nav{display:flex;flex-wrap:wrap;align-items:center;gap:.2rem 1.35rem;list-style:none;margin:0;padding:0}
.nav a{text-decoration:none;font-size:.95rem;letter-spacing:.015em;padding:.3rem 0;border-bottom:2px solid transparent;color:var(--graphite)}
.nav a:hover{border-bottom-color:var(--brass);color:var(--ink)}
.nav a[aria-current="page"]{border-bottom-color:var(--ink);font-weight:600;color:var(--ink)}
.nav a.btn{border-bottom:2px solid var(--ink);color:#fff}

/* buttons */
.btn{display:inline-block;background:var(--ink);color:#fff;text-decoration:none;padding:.78rem 1.4rem;border-radius:2px;font-weight:600;letter-spacing:.02em;border:2px solid var(--ink);transition:background .15s,border-color .15s}
.btn:hover{background:var(--navy-deep);border-color:var(--navy-deep);color:#fff}
.btn-sm{padding:.42rem .85rem;font-size:.92rem}
.btn-ghost{background:transparent;color:var(--ink)}
.btn-ghost:hover{background:var(--ink);border-color:var(--ink);color:#fff}
.actions{display:flex;flex-wrap:wrap;gap:.8rem;margin-top:1.3rem}

/* worked-example sheet: the yellow legal pad I work on with students */
.pad{
  background-color:#fbf1a0;
  background-image:
    linear-gradient(to right,transparent 2.7rem,rgba(184,48,48,.7) 2.7rem,rgba(184,48,48,.7) 2.75rem,transparent 2.75rem,transparent 2.88rem,rgba(184,48,48,.7) 2.88rem,rgba(184,48,48,.7) 2.93rem,transparent 2.93rem),
    repeating-linear-gradient(to bottom,transparent 0,transparent calc(var(--line) - 1px),#8fb3d6 calc(var(--line) - 1px),#8fb3d6 var(--line));
  background-position:0 0,0 .9rem;
  line-height:var(--line);
  padding:.9rem 1.2rem .9rem 3.8rem;
  border:1px solid #e0cd6a;border-top:.65rem solid #d4b73c;border-radius:3px;
  box-shadow:0 1px 2px rgba(60,48,0,.18),0 18px 36px -18px rgba(22,40,75,.4);
}
.pad p,.pad li{margin:0}
.pad .ink{font-family:var(--serif);font-style:italic;color:var(--ink);font-size:1.1rem}
.pad .gap{height:var(--line)}

/* hero: text, then the annotated normal curve from the business card */
.hero{padding:3.6rem 0 1.6rem;border-bottom:1px solid var(--rule);background:var(--paper)}
.hero-grid{display:grid;gap:3rem;grid-template-columns:1.15fr 1fr;align-items:start}
.hero h1{margin-bottom:1.1rem}
@media (max-width:52rem){.hero-grid{grid-template-columns:1fr}}
.hero-curve{margin-top:2.4rem;--cv-ink:#16284b;--cv-muted:#4d5568}
.cv{display:block;width:100%;height:auto;overflow:visible;font-family:var(--serif);font-style:italic}
.cv-b0{fill:#b7c8e0}.cv-b1{fill:#cbd9c4}.cv-b2{fill:#e4d3a1}.cv-b3{fill:#cfa49d}
.cv-line{fill:none;stroke:var(--cv-ink);stroke-width:1.8;stroke-linejoin:round}
.cv-axis{stroke:var(--cv-ink);stroke-width:1.3}
.cv-sep{stroke:var(--cv-ink);stroke-width:1.6;stroke-opacity:.7}
.cv-mu{stroke-dasharray:5 4;stroke-opacity:.55}
.cv-dot{fill:var(--margin);stroke:#fff;stroke-width:1.5}
.cv-arrow{fill:none;stroke:var(--cv-muted);stroke-width:1.1;stroke-dasharray:3 3}
.cv-text{fill:var(--cv-ink);font-size:17px}
.cv-head{fill:var(--cv-ink);font-size:20px;font-weight:600}
.cv-small{fill:var(--cv-muted);font-size:14.5px}
.cv-pct{fill:var(--cv-ink);font-size:15px;font-style:normal;font-weight:600;font-family:var(--sans)}
.cv-onband line{stroke:#16284b;stroke-width:1.4}
.cv-onband text{fill:#16284b;font-size:17px}
.cv-bar line{stroke:var(--cv-ink);stroke-width:1.4}
.cv-bg{paint-order:stroke;stroke:var(--paper);stroke-width:7px;stroke-linejoin:round}
@media (max-width:52rem){
  .hero-curve{aspect-ratio:1200 / 315;overflow:hidden;margin-top:1.6rem}
  .cv-detail{display:none}
}

/* sections */
section.block{padding:3.4rem 0;border-top:1px solid #e4e1d6}
section.block:first-of-type{border-top:0}
.tint{background:var(--soft);border-top:1px solid #e4e1d6;border-bottom:1px solid #e4e1d6}
.cols-3,.cols-2{display:grid;gap:2rem}
.cols-3{grid-template-columns:repeat(3,1fr)}
.cols-2{grid-template-columns:repeat(2,1fr)}
@media (max-width:52rem){.cols-3,.cols-2{grid-template-columns:1fr}}
.col h3{padding-top:.75rem;border-top:2px solid var(--rule)}
.col-good h3{border-top-color:var(--ink)}
.col-not h3{border-top-color:var(--margin)}
.checks{list-style:none;padding:0;margin:0}
.checks li{position:relative;padding-left:1.6rem;margin-bottom:.55rem}
.checks li::before{content:"";position:absolute;left:.15rem;top:.62rem;width:.45rem;height:.45rem;background:var(--brass);transform:rotate(45deg)}
.col-not .checks li::before{background:var(--margin);transform:none;width:.6rem;height:2px;top:.85rem}

/* subject links */
.subject-list{display:grid;grid-template-columns:repeat(auto-fit,minmax(15rem,1fr));gap:0 2rem;list-style:none;padding:0;margin:1.2rem 0 0}
.subject-list li{border-top:1px solid var(--rule);padding:.9rem 0}
.subject-list a{font:600 1.15rem var(--serif);text-decoration:none}
.subject-list a:hover{text-decoration:underline;text-decoration-color:var(--brass);text-underline-offset:.25em}
.subject-list p{margin:.2rem 0 0;font-size:.97rem;color:var(--muted)}

/* tables */
.table-wrap{overflow-x:auto;margin:1rem 0 1.5rem}
table{border-collapse:collapse;width:100%;min-width:30rem}
caption{text-align:left;font:600 1.1rem var(--serif);color:var(--ink);padding-bottom:.4rem}
th,td{text-align:left;padding:.65rem .8rem;border-bottom:1px solid var(--rule);vertical-align:top}
thead th{border-bottom:2px solid var(--ink);font-size:.8rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
td.num{font-variant-numeric:tabular-nums;white-space:nowrap}

/* pull quote */
.quote{margin:2rem 0}
.quote{border-left:2px solid var(--brass);padding-left:1.2rem}
.quote p{font:italic 1.35rem/1.5 var(--serif);color:var(--ink);margin:0}
.quote cite{display:block;margin-top:.4rem;font:.95rem var(--sans);font-style:normal;color:var(--muted)}

/* notes / callouts */
.note{border-left:3px solid var(--brass);background:var(--soft);padding:1rem 1.2rem;margin:1.5rem 0}
.note p:last-child{margin-bottom:0}

/* prose pages */
.page-head{padding:2.8rem 0 1.5rem;border-bottom:1px solid var(--rule);background:var(--paper) url(../img/bell-faint.svg) right bottom/min(44rem,62%) 6rem no-repeat}
@media (max-width:52rem){.page-head{background-size:90% 4rem}}
.page-head .lede{margin-bottom:0}
.prose{max-width:44rem}
.wrap.prose{width:min(44rem,100% - 2.5rem);margin-left:max(1.25rem,calc((100% - 68rem)/2))}
.prose h2{margin-top:2.2rem}
.prose ul{padding-left:1.2rem}
.prose li{margin-bottom:.4rem}
.crumbs{font-size:.9rem;color:var(--muted);margin-bottom:.6rem}
.crumbs a{color:var(--muted)}

/* faq */
details.qa{border-top:1px solid var(--rule);padding:.9rem 0}
details.qa:last-of-type{border-bottom:1px solid var(--rule)}
details.qa summary{cursor:pointer;font:600 1.1rem var(--serif);color:var(--ink);list-style:none;padding-right:2rem;position:relative}
details.qa summary::-webkit-details-marker{display:none}
details.qa summary::after{content:"+";position:absolute;right:0;top:-.1rem;font:400 1.5rem var(--sans);color:var(--brass)}
details.qa[open] summary::after{content:"\2212"}
details.qa .qa-body{padding-top:.6rem}
details.qa .qa-body p:last-child{margin-bottom:0}

/* video */
.video{position:relative;aspect-ratio:16/9;background:#000;max-width:42rem}
.video iframe,.video-play{position:absolute;inset:0;width:100%;height:100%;border:0}
.video-play{padding:0;background:#000;cursor:pointer}
.video-play img{width:100%;height:100%;object-fit:cover;opacity:.88}
.video-icon{position:absolute;left:50%;top:50%;width:4.2rem;height:3rem;transform:translate(-50%,-50%);background:var(--ink);border:2px solid #fff;border-radius:.8rem}
.video-icon::after{content:"";position:absolute;left:1.7rem;top:.8rem;border-left:1.1rem solid #fff;border-top:.7rem solid transparent;border-bottom:.7rem solid transparent}
.video-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(18rem,1fr));gap:2rem}

/* forms */
form.inquiry{max-width:40rem}
.field{margin-bottom:1.2rem}
label,legend{display:block;font-weight:600;margin-bottom:.25rem}
.hint{font-weight:400;color:var(--muted);font-size:.93rem;display:block}
input[type=text],input[type=email],select,textarea{width:100%;font:inherit;padding:.65rem .7rem;border:1px solid #aeb8cb;background:#fff;border-radius:2px;color:var(--graphite)}
textarea{min-height:7rem;resize:vertical}
input:focus,select:focus,textarea:focus{border-color:var(--ink);box-shadow:0 0 0 2px rgba(22,40,75,.15)}
.check{display:flex;gap:.7rem;align-items:flex-start;font-weight:400}
.check input{margin-top:.4rem;width:1.1rem;height:1.1rem}
.hp{position:absolute;left:-9999px;height:0;overflow:hidden}
.alert{padding:1rem 1.2rem;margin-bottom:1.5rem;border-left:3px solid var(--margin);background:#fbefee}
.alert.ok{border-left-color:var(--ink);background:#edf0f8}
.alert ul{margin:.4rem 0 0;padding-left:1.2rem}

/* footer */
.foot{margin-top:3rem;background:var(--navy-deep);color:#e8e3d3;border-top:3px solid var(--brass);padding:2.6rem 0 1.4rem}
.foot-in{display:grid;grid-template-columns:1.2fr 1fr;gap:2rem}
.foot-brand{font:600 1.35rem var(--serif);color:#fff;margin-bottom:.5rem}
.foot-links{list-style:none;padding:0;margin:0;columns:2;column-gap:1.5rem}
.foot-links li{margin-bottom:.4rem}
.foot a{color:#f0deaa;text-underline-offset:.2em}
.foot a:hover{color:#fff}
.foot-fine{margin-top:1.6rem;padding-top:1rem;border-top:1px solid rgba(232,227,211,.2);font-size:.9rem;color:#b9b7ab}
@media (max-width:52rem){.foot-in{grid-template-columns:1fr}}

@media print{
  .top,.foot,.actions,.skip,.video{display:none}
  body{font-size:11pt;background:#fff}
  a{color:#000}
}


.video-play img.poster{opacity:1}

/* cartoon video: the cartoon stays on screen; the player is a small inset */
.video-play svg.toon-art{width:100%;height:100%;display:block}
.video.toon:not(.talk-art).playing .video-play{pointer-events:none;cursor:default}
.video.toon:not(.talk-art).playing .bub2{opacity:0}
.video .toon-player{inset:auto 2% 3% auto;width:38%;height:auto;aspect-ratio:16/9;border:3px solid var(--paper);background:#000;box-shadow:0 4px 14px rgba(0,0,0,.35);z-index:2}
@media (max-width:600px){
  .video.toon:not(.talk-art).playing{aspect-ratio:auto;background:none}
  .video.toon:not(.talk-art).playing .video-play{position:relative;height:auto;aspect-ratio:16/9}
  .video .toon-player{position:relative;inset:auto;width:100%;margin-top:.5rem}
}

/* cartoon that speaks the introduction audio */
.talk{max-width:42rem}
.talk .video{max-width:none}
.talk-art .video-play{cursor:pointer}
.talk-art.playing .video-icon{display:none}
.talk-art.playing .bub2{opacity:0}
.talk-audio{display:block;width:100%;margin-top:.5rem}
.talk-cc{margin-top:.5rem;min-height:4.1rem;padding:.5rem .9rem;background:var(--navy-deep);color:#fff;border-radius:3px;font:600 1.1rem/1.4 var(--sans);text-align:center;display:flex;align-items:center;justify-content:center}
.talk-cc.off{display:none}
.talk-bar{margin-top:.4rem;text-align:right}
.talk-cc-btn{font:inherit;font-size:.9rem;padding:.2rem .7rem;border:1px solid var(--ink);background:var(--paper);color:var(--ink);border-radius:2px;cursor:pointer}
.talk-cc-btn:hover{background:var(--soft)}
.talk-cc-btn[aria-pressed="false"]{color:var(--muted);border-color:var(--rule)}
.talk-tx{margin-top:.6rem;font-size:.98rem}
.talk-tx summary{cursor:pointer;color:var(--ink);font-weight:600}
.talk-tx p{margin:.6rem 0 0}
.mini-cal{margin-top:.8rem;max-width:40rem}
.mini-cal iframe{display:block;width:100%;height:460px;border:1px solid var(--rule,#d9d4c7);background:#fff}
.mini-cal .small{margin:.4rem 0 0}

/* essays, references and the Yelp band (added 2026-10-11) */
.essay h2{margin-top:2rem}
.essay .for{font:.95rem var(--sans);color:var(--muted);margin:0 0 1.2rem}
.essay .work{font:1.1rem/1.7 var(--serif);background:#f6f4ec;border-left:2px solid var(--brass);padding:.7rem 1rem;margin:1rem 0;overflow-x:auto}
.essay .work p{margin:.15rem 0}
.refs blockquote.ref{margin:1.6rem 0;padding:0 0 0 1.1rem;border-left:2px solid var(--brass)}
.refs blockquote.ref p{margin:0 0 .6rem}
.refs blockquote.ref cite{display:block;font:.95rem var(--sans);font-style:normal;color:var(--muted)}
.refs .ref-sub{font:.95rem var(--sans);color:var(--muted);margin:2rem 0 -.6rem}
.yelp-band{background:#101c36;color:#fff;padding:1.6rem 0}
.yelp-band .wrap{display:flex;flex-wrap:wrap;gap:1rem 2rem;align-items:center;justify-content:space-between}
.yelp-band p{margin:0}
.yelp-band .stars{font-size:1.9rem;letter-spacing:.12em;color:#ffcf4a;line-height:1}
.yelp-band .yb-line{font:1.2rem/1.4 var(--serif)}
.yelp-band .yb-sub{font:.95rem var(--sans);color:#cfd6e6;margin-top:.25rem}
.yelp-band a.btn{white-space:nowrap}
.yelp-band a:not(.btn){color:#ffe98a}
.home-quotes{display:grid;gap:1.4rem;grid-template-columns:repeat(auto-fit,minmax(16rem,1fr));margin:1.4rem 0}
.home-quotes .quote{margin:0}
.home-quotes .quote p{font-size:1.1rem}
.yelp-band .btn{background:#ffe98a;color:#101c36;border-color:#ffe98a}
.yelp-band .btn:hover{background:#fff;border-color:#fff;color:#101c36}