/* Lesson visuals (tables, equations, plots, figures, callouts, worked-example step cards) in the Chemistry I color code:
   gold = clue and route, blue = worked example, green = check/answer, navy = key equation, slate = the idea. */
.lede{line-height:1.7}
p.txt,.we-body p,.co-b,.cmp-b,.keypoints li{line-height:1.75}
.concept{display:flex;flex-direction:column;gap:1.5rem}
.blk{margin:0;min-width:0}
.blk-title{font-family:var(--display);font-weight:600;font-size:1.08rem;margin-bottom:.6rem}
.cap{color:var(--muted);font-size:.92rem;margin-top:.6rem;line-height:1.55}
/* fractions and nuclear notation */
.frac{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;margin:0 .2em;line-height:1.25}
.frac .fn{border-bottom:1.5px solid currentColor;padding:0 .3em .1em}
.frac .fd{padding:.1em .3em 0}
.nuc{display:inline-flex;align-items:center;gap:1px;white-space:nowrap}
.nuc-az{display:inline-flex;flex-direction:column;align-items:flex-end;font-size:.72em;line-height:1.05;margin-right:2px}
/* display equations */
.eq{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:1.3rem 1.2rem;display:flex;flex-direction:column;align-items:stretch;gap:.9rem;overflow-x:auto}
.eq.boxed{border:0;border-left:5px solid var(--navy);background:var(--navy-soft);border-radius:0 12px 12px 0}
.eq .blk-title{color:var(--navy);font-size:.82rem;letter-spacing:.1em;text-transform:uppercase;font-family:var(--body);font-weight:800;margin:0;text-align:center}
.eq-line{font-family:var(--display);font-size:1.3rem;white-space:nowrap;text-align:center;width:max-content;max-width:none;margin-inline:auto}
.eq.boxed .eq-line{font-weight:600}
.eq .cap{margin-top:0;text-align:center}
.we-body .eq{padding:1rem;background:var(--blue-soft);border-color:transparent}
.we-body .eq-line{font-size:1.15rem}
/* tables */
.tablebox{overflow-x:auto;-webkit-overflow-scrolling:touch}
.tbl-fig .tablebox{background:var(--surface);border:1px solid var(--line);border-radius:12px}
.tbl{width:100%;border-collapse:collapse;font-size:1rem}
.tbl th,.tbl td{padding:.75rem 1rem;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}
.tbl thead th{background:var(--navy-soft);color:var(--navy);font-size:.95rem;font-weight:700}
.tbl tbody tr:nth-child(even) td{background:color-mix(in srgb,var(--slate-soft) 55%,transparent)}
.tbl tbody tr:last-child td,.tbl tbody tr:last-child th{border-bottom:0}
.tbl.rowhead tbody th{font-family:var(--display);font-size:1.08rem;color:var(--purple);min-width:3rem;white-space:nowrap}
.tbl.center td{text-align:center}.tbl.center thead th:not(:first-child){text-align:center}
.tbl td.hl,.tbl th.hl{background:var(--gold-soft)!important;color:var(--ink);font-weight:700}
.we-body .tbl-fig .tablebox{background:var(--surface)}
/* figures and plots */
.figbox{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:1rem;overflow-x:auto;-webkit-overflow-scrolling:touch}
.figbox svg{display:block;width:100%;height:auto;max-width:640px;margin:0 auto;min-width:300px}
.plot text,.figbox svg text{font-family:var(--body)}
.pl-tick{font-size:13px;fill:var(--muted)}
.pl-axis{font-size:14px;fill:var(--ink);font-weight:700}
.pl-lab{font-size:14px;font-weight:700}
/* compare cards */
.cmp-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(13rem,1fr));gap:.9rem}
.cmp{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:1.1rem;display:flex;flex-direction:column;gap:.45rem;min-width:0}
.cmp-h{font-weight:700}
.cmp.good{border-color:var(--green);background:var(--green-soft)}.cmp.good .cmp-h{color:var(--green)}
.cmp.bad{border-color:var(--red);background:var(--red-soft)}.cmp.bad .cmp-h{color:var(--red)}
.cmp.calm{background:var(--surface);border-top:4px solid var(--navy)}.cmp.calm .cmp-h{color:var(--navy)}
.cmp-b{font-size:1rem}
/* callouts with Ruby */
.callout{display:flex;gap:1rem;align-items:flex-start;background:var(--surface);border:1px solid var(--line);border-left:5px solid var(--c,var(--navy));border-radius:0 14px 14px 0;padding:1rem 1.2rem}
.callout .mascot{width:58px;height:58px;flex:none}
.callout .co-h{font-weight:800;margin-bottom:.2rem;color:var(--c,var(--navy))}
.callout.tip{--c:var(--navy);background:var(--navy-soft);border-color:transparent;border-left-color:var(--navy)}
.callout.watch{--c:var(--red);background:var(--red-soft);border-color:transparent;border-left-color:var(--red)}
.callout.remember{--c:var(--green);background:var(--green-soft);border-color:transparent;border-left-color:var(--green)}
.callout.why{--c:var(--purple);background:var(--purple-soft);border-color:transparent;border-left-color:var(--purple)}
/* key points */
.keypoints ul{margin:0;padding:0;list-style:none;display:flex;flex-direction:column;gap:.6rem}
.keypoints li{padding-left:1.75rem;position:relative}
.keypoints li::before{content:"";position:absolute;left:.35rem;top:.72em;width:.55rem;height:.55rem;border-radius:2px;transform:rotate(45deg);background:var(--purple)}
/* route: numbered gold steps */
.route{list-style:none;padding:0;margin:0;counter-reset:r;display:flex;flex-direction:column;gap:.85rem}
.route li{counter-increment:r;display:grid;grid-template-columns:2.2rem minmax(0,1fr);gap:.8rem;align-items:start;line-height:1.7}
.route li::before{content:counter(r);width:2rem;height:2rem;border-radius:50%;background:var(--gold);color:var(--on-accent);font-weight:800;display:grid;place-items:center;font-size:.95rem}
/* worked example */
.example{background:var(--surface);border:1px solid var(--line);border-top:5px solid var(--blue);border-radius:var(--r);padding:clamp(1.25rem,3vw,1.9rem);box-shadow:var(--shadow);display:flex;flex-direction:column;gap:1.4rem}
.ex-q{display:flex;flex-direction:column;gap:1rem}
.ex-q h3{font-family:var(--body);font-weight:700;font-size:var(--s1);line-height:1.45;letter-spacing:0}
.predict{font-size:.98rem;color:var(--muted)}
.ex-steps{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:1.2rem}
.we-step{display:grid;grid-template-columns:2.6rem minmax(0,1fr);gap:1rem;animation:pop .3s ease-out}
.we-num{width:2.4rem;height:2.4rem;border-radius:50%;background:var(--blue);color:var(--on-accent);font-weight:700;display:grid;place-items:center;font-family:var(--display);font-size:1.05rem}
.we-step.answer .we-num{background:var(--green)}
.we-body{display:flex;flex-direction:column;gap:.85rem;min-width:0;padding-bottom:1.2rem;border-bottom:1px solid var(--line)}
.we-step.answer .we-body{border-bottom:0;background:var(--green-soft);border-radius:12px;padding:1rem 1.1rem}
.we-body .lab{font-size:.82rem;letter-spacing:.08em;text-transform:uppercase;color:var(--blue);font-weight:800}
.we-step.answer .lab{color:var(--green)}
.we-step.answer .we-body>p{font-weight:700;font-size:1.1rem}
.example [data-we-next]{align-self:flex-start}
@media (max-width:560px){
  .example{padding:1rem .9rem}
  .we-step{grid-template-columns:minmax(0,1fr);gap:.5rem}
  .we-num{width:1.9rem;height:1.9rem;font-size:.9rem}
  .eq-line{font-size:1.1rem}
  .callout{flex-direction:column}
  .callout .mascot{width:48px;height:48px}
  .tbl th,.tbl td{min-width:5.2rem;padding:.6rem .65rem}
  .tbl.rowhead tbody th{min-width:2.4rem;white-space:normal}
  .figbox{padding:.6rem}
  .figbox svg{min-width:470px}
}
/* phones: figures fit the screen; tap to enlarge (same as Chemistry I) */
@media (max-width:560px){
  .figbox svg{min-width:480px}
  .figbox{cursor:zoom-in}
  .fig .figbox + .cap::after{content:" Tap the picture to enlarge it.";font-style:italic}
  .fig:not(:has(.cap))::after{content:"Tap the picture to enlarge it.";display:block;font-style:italic;color:var(--muted);font-size:.85rem;margin-top:.4rem}
  .figbox.more{-webkit-mask-image:linear-gradient(90deg,#000 calc(100% - 28px),transparent);mask-image:linear-gradient(90deg,#000 calc(100% - 28px),transparent)}
  .figbox.more.end{-webkit-mask-image:none;mask-image:none}
}
#zoom{position:fixed;inset:0;z-index:60;background:color-mix(in srgb,var(--paper) 96%,transparent);display:flex;flex-direction:column;padding:max(12px,env(safe-area-inset-top,0px)) max(12px,env(safe-area-inset-right,0px)) max(12px,env(safe-area-inset-bottom,0px)) max(12px,env(safe-area-inset-left,0px))}
#zoom .zbar{display:flex;justify-content:space-between;align-items:center;gap:1rem;padding-bottom:.6rem;font-weight:700;color:var(--muted)}
#zoom .zbar button{min-width:44px;min-height:44px;border:2px solid var(--navy);border-radius:999px;background:var(--surface);color:var(--navy);font-weight:700;padding:0 1rem;cursor:pointer}
#zoom .zbody{flex:1;overflow:auto;-webkit-overflow-scrolling:touch;background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:12px}
#zoom .zbody svg{display:block;width:760px;max-width:none;height:auto}
/* labels that can contain chemistry keep their case (pH, Ka, mL) */
.we-body .lab{text-transform:none;letter-spacing:0;font-size:1.02rem}
.eq .blk-title{text-transform:none;letter-spacing:.01em;font-size:.95rem}
.nuc{vertical-align:middle}
/* wide tables/equations on small screens: a fade on the right edge says "there's more, swipe" */
.tablebox.more,.eq.more{-webkit-mask-image:linear-gradient(90deg,#000 calc(100% - 28px),transparent);mask-image:linear-gradient(90deg,#000 calc(100% - 28px),transparent)}
.tablebox.more.end,.eq.more.end{-webkit-mask-image:none;mask-image:none}
.tbl.center tbody td:first-child{text-align:left}
.swipe-cue{margin:.35rem 0 0;font-size:.82rem;color:var(--muted);text-align:right}

/* artwork from the Chemistry I lessons */
.c2 .figbox img{display:block;max-width:100%;height:auto;margin:0 auto}

/* explain-more parts: hook, route reason, refutation, three levels, self-check */
.c2 .hook,.hook{margin:.2rem 0 .5rem;font-family:var(--display);font-size:1.12rem;color:var(--course);font-style:italic}
.route .r-why{display:block;margin-top:.2rem;font-size:.9rem;color:var(--muted);line-height:1.4}
.route .r-why b{color:var(--ink);font-weight:600}
.blk.refute{border-radius:14px;overflow:hidden;border:1px solid var(--line)}
.refute .rf-row{display:grid;grid-template-columns:8.5rem 1fr;gap:.8rem;padding:.75rem 1rem;align-items:start}
.refute .rf-think{background:var(--red-soft)}
.refute .rf-actually{background:var(--green-soft)}
.refute .rf-k{font-weight:700;font-size:.85rem;text-transform:uppercase;letter-spacing:.04em}
.refute .rf-think .rf-k{color:var(--red)}.refute .rf-actually .rf-k{color:var(--green)}
.refute .rf-think span:last-child{text-decoration:line-through;text-decoration-color:color-mix(in srgb,var(--red) 55%,transparent);text-decoration-thickness:1.5px}
.levels .lv-row{display:grid;grid-template-columns:repeat(3,1fr);gap:.6rem}
.levels .lv{border:1px solid var(--line);border-radius:12px;padding:.7rem .85rem;background:var(--surface)}
.levels .lv-h{font-size:.78rem;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);margin-bottom:.3rem}
.levels .lv-particles{border-color:color-mix(in srgb,var(--course) 45%,var(--line));background:var(--course-soft)}
.selfcheck{border:1px dashed var(--line);border-radius:14px;padding:1rem 1.1rem;background:var(--surface)}
.selfcheck .sc-q{font-weight:600;font-size:1.05rem;margin:0}
.selfcheck .sc-say{margin:.3rem 0 .6rem;color:var(--muted);font-size:.9rem}
.selfcheck summary{cursor:pointer;font-weight:600;color:var(--course)}
.selfcheck details p{margin:.5rem 0 0}
@media (max-width:560px){.levels .lv-row{grid-template-columns:1fr}.refute .rf-row{grid-template-columns:1fr;gap:.2rem}}