/* ds.css — Distributed Systems (reworked) course components.
   Loaded after lesson-kit.css. Uses only the --lk-* tokens. Borders-only surfaces, 0-4px radii. */

/* ---------- chapter opening ---------- */
.ds-sources{display:flex;flex-wrap:wrap;gap:.4rem;margin:.7rem 0 0;font-family:var(--lk-mono);font-size:.74rem}
.ds-sources span{border:1px solid var(--lk-rule-soft);border-radius:2px;padding:.08rem .45rem;color:var(--lk-ink-soft);background:var(--lk-paper-light)}
.ds-sources span b{color:var(--lk-cobalt);font-weight:600}

.ds-spine{margin:1.6rem 0 1.2rem;padding:0 0 0 1.1rem;border-left:3px solid var(--lk-vermilion)}
.ds-spine .ds-label{display:block;font-family:var(--lk-utility);font-size:.7rem;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--lk-vermilion);margin-bottom:.2rem}
.ds-spine p{font-size:1.32rem!important;line-height:1.4;margin:0;font-style:italic;color:var(--lk-ink)}

.ds-thesis{background:var(--lk-paper-light);border:1px solid var(--lk-rule-soft);border-radius:3px;padding:1rem 1.2rem;margin:1.2rem 0 1.6rem}
.ds-thesis .ds-label{display:block;font-family:var(--lk-utility);font-size:.7rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--lk-cobalt);margin-bottom:.35rem}
.ds-thesis p{margin:.3rem 0}

/* compact contents strip */
.ds-contents{margin:1.2rem 0 2rem;font-family:var(--lk-utility);font-size:.86rem;border-top:1px solid var(--lk-rule-soft);border-bottom:1px solid var(--lk-rule-soft);padding:.6rem 0}
.ds-contents ol{margin:0;padding:0;list-style:none;display:flex;flex-wrap:wrap;gap:.25rem 1.1rem;counter-reset:dsc}
.ds-contents li{counter-increment:dsc;font-size:.86rem!important}
.ds-contents li::before{content:counter(dsc)" ";font-family:var(--lk-mono);color:var(--lk-vermilion);font-size:.8em}
.ds-contents a{text-decoration:none}
.ds-contents a:hover{text-decoration:underline}

/* ---------- definitions & terms ---------- */
body.lk dfn{font-style:normal;font-weight:700;color:var(--lk-ink)}
.defn{margin:1.3rem 0;padding:.85rem 1.05rem;border:1px solid var(--lk-rule);border-radius:3px;background:var(--lk-paper-light)}
.defn .defn-term{display:flex;justify-content:space-between;gap:1rem;flex-wrap:wrap;align-items:baseline;margin-bottom:.3rem}
.defn .defn-term b{font-family:var(--lk-utility);font-size:.72rem;letter-spacing:.1em;text-transform:uppercase;color:var(--lk-cobalt)}
.defn .defn-term cite{font-family:var(--lk-mono);font-size:.74rem;font-style:normal;color:var(--lk-ink-soft)}
.defn p{margin:.3rem 0}
.defn p:last-child{margin-bottom:0}
.defn .math,.ds-math{font-family:var(--lk-mono);font-size:.95rem;color:var(--lk-cobalt-dark);display:block;margin:.5rem 0;padding:.45rem .7rem;background:var(--lk-paper);border:1px solid var(--lk-rule-soft);border-radius:2px;overflow-x:auto;white-space:nowrap}

/* countable enumerations: every professor list stays numbered and complete */
ol.ds-count{list-style:none;padding:0;margin:1.1rem 0;counter-reset:dsn;border-top:1px solid var(--lk-rule-soft)}
ol.ds-count>li{counter-increment:dsn;position:relative;padding:.55rem 0 .55rem 2.6rem;border-bottom:1px solid var(--lk-rule-soft);margin:0}
ol.ds-count>li::before{content:counter(dsn);position:absolute;left:0;top:.5rem;width:1.8rem;text-align:right;font-family:var(--lk-display);font-weight:700;font-size:1.25rem;line-height:1.2;color:var(--lk-vermilion)}
ol.ds-count>li>b:first-child,ol.ds-count>li>strong:first-child{color:var(--lk-ink)}
.ds-count-head{font-family:var(--lk-utility);font-size:.74rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--lk-ink-soft);margin:1.4rem 0 -.6rem}

/* ---------- asides ---------- */
.beyond{margin:1.3rem 0;padding:.8rem 1.05rem;border:1px dashed var(--lk-forest);border-radius:3px;background:transparent}
.beyond .ds-label,.slidefix .ds-label,.ds-aside-label{display:block;font-family:var(--lk-utility);font-size:.68rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;margin-bottom:.3rem}
.beyond .ds-label{color:var(--lk-forest)}
.beyond p:last-child,.slidefix p:last-child{margin-bottom:0}
.slidefix{margin:1.3rem 0;padding:.8rem 1.05rem;border:1px solid var(--lk-vermilion);border-radius:3px;background:var(--lk-warnbg)}
.slidefix .ds-label{color:var(--lk-vermilion)}

/* cross-chapter reference chip */
a.xref{font-family:var(--lk-mono);font-size:.8em;text-decoration:none;border:1px solid var(--lk-rule-soft);border-radius:2px;padding:0 .3rem;white-space:nowrap;background:var(--lk-paper-light)}
a.xref:hover{border-color:var(--lk-cobalt)}

/* ---------- comparison grid (two or three columns that collapse) ---------- */
.ds-versus{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:.7rem;margin:1.3rem 0}
.ds-versus>div{border:1px solid var(--lk-rule-soft);border-radius:3px;padding:.75rem .9rem;background:var(--lk-paper-light)}
.ds-versus h4{margin:0 0 .35rem;font-family:var(--lk-utility);font-size:.8rem;letter-spacing:.06em;text-transform:uppercase;color:var(--lk-cobalt)}
.ds-versus p,.ds-versus li{font-size:.97rem!important}
.ds-versus p:last-child{margin-bottom:0}

/* ---------- instruments (widgets) ---------- */
.ds-inst{margin:1.8rem 0;border:1px solid var(--lk-rule);border-radius:3px;background:var(--lk-paper-light)}
.ds-inst>header{display:flex;justify-content:space-between;align-items:baseline;gap:1rem;flex-wrap:wrap;padding:.6rem .9rem;border-bottom:1px solid var(--lk-rule-soft)}
.ds-inst>header b{font-family:var(--lk-utility);font-size:.72rem;letter-spacing:.1em;text-transform:uppercase;color:var(--lk-vermilion)}
.ds-inst>header span{font-family:var(--lk-display);font-size:1.02rem;font-weight:700;text-transform:uppercase;color:var(--lk-cobalt-dark)}
.ds-inst .ds-inst-body{padding:.8rem .9rem}
.ds-inst .ds-inst-howto{font-size:.9rem!important;color:var(--lk-ink-soft);margin:0 0 .6rem}
.ds-inst noscript p,.ds-inst .ds-fallback{font-size:.92rem;color:var(--lk-ink-soft)}

.ds-seg{display:inline-flex;flex-wrap:wrap;border:1px solid var(--lk-rule);border-radius:3px;overflow:hidden}
.ds-seg button{font:600 .8rem var(--lk-utility);padding:.38rem .7rem;border:0;border-right:1px solid var(--lk-rule-soft);background:var(--lk-paper-light);color:var(--lk-ink-soft);cursor:pointer}
.ds-seg button:last-child{border-right:0}
.ds-seg button[aria-pressed="true"]{background:var(--lk-cobalt);color:var(--lk-paper-light)}
.ds-seg button:hover:not([aria-pressed="true"]){background:var(--lk-hl)}
.ds-btn{font:600 .8rem var(--lk-utility);padding:.38rem .75rem;border:1px solid var(--lk-rule);border-radius:3px;background:var(--lk-paper-light);color:var(--lk-ink);cursor:pointer}
.ds-btn:hover{border-color:var(--lk-cobalt);background:var(--lk-hl)}
.ds-btn.primary{background:var(--lk-cobalt);border-color:var(--lk-cobalt);color:var(--lk-paper-light)}
.ds-btn.primary:hover{background:var(--lk-cobalt-dark)}
.ds-btn:disabled{opacity:.4;cursor:not-allowed}
.ds-row{display:flex;flex-wrap:wrap;gap:.5rem;align-items:center;margin:.45rem 0}
.ds-row label{font:.8rem var(--lk-utility);color:var(--lk-ink-soft);display:inline-flex;gap:.35rem;align-items:center}
.ds-row select{font:.82rem var(--lk-utility);padding:.3rem .4rem;border:1px solid var(--lk-rule);border-radius:3px;background:var(--lk-paper)}
.ds-readout{font:.9rem/1.55 var(--lk-font);background:var(--lk-paper);border:1px solid var(--lk-rule-soft);border-radius:3px;padding:.6rem .8rem;margin-top:.6rem;min-height:3em}
.ds-readout code{font-size:.82em}
.ds-readout .ok{color:var(--lk-forest);font-weight:700}
.ds-readout .bad{color:var(--lk-vermilion);font-weight:700}
.ds-verdict{font:600 .88rem var(--lk-utility);padding:.45rem .7rem;border-radius:3px;margin-top:.5rem;background:var(--lk-paper);border:1px solid var(--lk-rule-soft)}
.ds-verdict.ok{background:var(--lk-okbg);color:var(--lk-forest);border-color:var(--lk-forest)}
.ds-verdict.bad{background:var(--lk-warnbg);color:var(--lk-vermilion);border-color:var(--lk-vermilion)}

/* space-time diagram */
.st-canvas{overflow-x:auto;border:1px solid var(--lk-rule-soft);border-radius:3px;background:var(--lk-paper);margin:.5rem 0}
.st-canvas svg{display:block;min-width:560px;width:100%;height:auto}
.st-canvas .st-ev{cursor:pointer}
.st-canvas .st-ev:focus{outline:none}
.st-canvas .st-ev:focus-visible circle.st-dot{stroke:var(--lk-vermilion);stroke-width:3}
.st [hidden]{display:none!important}
.st-legend{display:flex;flex-wrap:wrap;gap:.9rem;font:.75rem var(--lk-mono);color:var(--lk-ink-soft);margin:.3rem 0 0}
.st-legend i{display:inline-block;width:.75rem;height:.75rem;border-radius:50%;vertical-align:-1px;margin-right:.3rem;border:1.5px solid var(--lk-cobalt)}
.st-legend i.past{background:var(--lk-cobalt)}
.st-legend i.future{background:var(--lk-vermilion);border-color:var(--lk-vermilion)}
.st-legend i.conc{background:var(--lk-paper);border-style:dashed;border-color:var(--lk-rule)}
.st-legend i.sel{background:var(--lk-paper);border:3px solid var(--lk-ink)}

/* ---------- oral discussion + project lens ---------- */
.ds-oral h3{margin-top:1.4rem}
.ds-oral details summary{font-weight:600}
.ds-oral details summary::after{content:"  · outline";font:.72rem var(--lk-mono);color:var(--lk-ink-soft);font-weight:400}
.ds-project{margin:1.6rem 0;padding:.95rem 1.1rem;border:1px solid var(--lk-cobalt);border-radius:3px;background:var(--lk-hl)}
.ds-project .ds-label{display:block;font-family:var(--lk-utility);font-size:.7rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--lk-cobalt);margin-bottom:.3rem}
.ds-project p:last-child,.ds-project ul:last-child{margin-bottom:0}

/* ---------- slide coverage ---------- */
.ds-coverage table{font-size:.86rem}
.ds-coverage td:first-child{font-family:var(--lk-mono);font-size:.78rem;white-space:nowrap;color:var(--lk-ink-soft)}
.ds-coverage td:last-child{white-space:nowrap}

/* ---------- small helpers ---------- */
.ds-kbd{font:.8em var(--lk-mono);border:1px solid var(--lk-rule);border-bottom-width:2px;border-radius:3px;padding:0 .3rem;background:var(--lk-paper-light)}
.ds-muted{color:var(--lk-ink-soft)}
.ds-center{text-align:center}
@media (max-width:640px){
  .ds-spine p{font-size:1.15rem!important}
  ol.ds-count>li{padding-left:2.2rem}
}
@media print{ .ds-inst{display:none} }

/* scroll hints only when a diagram really overflows (class toggled by lesson-kit.js) */
body.lk .figure-diagram::before{display:none!important}
body.lk .figure-diagram.has-overflow::before{display:block!important;content:'↔ Scroll the diagram'}