/* Classroom slides appear at the start of every formal chapter. */
.lesson-slides{margin:20px 0 60px;border:1px solid #dae7f0;border-radius:20px;background:#f7fbfe;box-shadow:0 15px 40px #173e5a0c;overflow:hidden;scroll-margin-top:105px}.slides-toolbar{min-height:76px;padding:17px 24px;display:flex;align-items:center;justify-content:space-between;gap:18px;background:#f9fcfe;border-bottom:1px solid #e2ebf2}.slides-toolbar>div{display:flex;flex-direction:column;gap:2px}.slides-eyebrow{font:10px/1.5 ui-monospace,SFMono-Regular,Consolas,monospace;letter-spacing:2px;color:#6396b9}.slides-toolbar strong{font-size:16px;color:#24475e;line-height:1.5}.slides-fullscreen{background:#fff;border:1px solid #d7e5ef;color:#426e89;border-radius:9px;padding:7px 13px;font-size:12px;white-space:nowrap}.slides-fullscreen:hover{background:#eaf5fc}.slide-viewport{overflow:hidden;touch-action:pan-y;background:#f0f8fd}.slide-track{display:flex;transition:transform .38s cubic-bezier(.22,.61,.36,1);will-change:transform}.lecture-slide{position:relative;flex:0 0 100%;min-width:0;min-height:465px;overflow:hidden;background:radial-gradient(circle at 84% 24%,#dceffd,#f4faff 45%,#eaf5fc 100%);color:#1c3446}.lecture-slide:nth-child(4n+2){background:linear-gradient(135deg,#f9fbfd,#ebf5fb 75%)}.lecture-slide:nth-child(4n+3){background:linear-gradient(145deg,#edf8fb,#f6fafc 70%)}.lecture-slide-dark{background:radial-gradient(circle at 75% 34%,#2d5b75,#142f43 53%,#112638 100%);color:#e9f6ff}.lecture-slide-dark h3,.lecture-slide-dark .slide-lead{color:#f3f9ff}.lecture-slide-dark .slide-points{color:#c4dce9}.lecture-slide-dark .slide-kicker,.lecture-slide-dark .slide-page-number{color:#a8c6d8}.slide-grid{display:grid;grid-template-columns:minmax(0,1.04fr) minmax(0,.96fr);align-items:center;gap:27px;min-height:465px;padding:48px 46px 60px}.slide-copy{position:relative;z-index:2}.slide-kicker{display:inline-flex;align-items:center;gap:10px;margin-bottom:20px;color:#5489aa;letter-spacing:1.4px;font-size:11px}.slide-kicker:before{content:"";width:24px;height:2px;background:currentColor}.lecture-slide h3{font-size:clamp(26px,2.7vw,36px);line-height:1.32;letter-spacing:-.6px;margin:0 0 21px;color:#193a52}.slide-lead{font-size:16px;line-height:1.8;color:#44697f;margin:0 0 19px}.slide-points{list-style:none;padding:0;margin:0;display:grid;gap:9px;color:#496d80;font-size:13px;line-height:1.6}.slide-points li{position:relative;padding-left:18px}.slide-points li:before{content:"";position:absolute;left:0;top:.7em;width:5px;height:5px;border-radius:50%;background:#60a7d1}.slide-art{position:relative;z-index:1;min-width:0;display:grid;align-items:center}.lecture-slide:first-child .slide-art:before{content:"";position:absolute;inset:-60px -40px;background:url('./assets/cover_data_decisions.png') center/cover no-repeat;opacity:.26;pointer-events:none;mask-image:linear-gradient(90deg,transparent,#000 18%,#000 85%,transparent)}.slide-visual-content{position:relative;display:grid;gap:11px}.slide-visual-flow .visual-node,.slide-visual-cards .visual-node,.slide-visual-compare .visual-node,.slide-visual-metric .visual-node{display:flex;align-items:flex-start;gap:13px;padding:13px 16px;border:1px solid #ccdfeb;background:#ffffffc9;border-radius:11px;box-shadow:0 5px 14px #1849690a}.lecture-slide-dark .visual-node{background:#345a72b0;border-color:#60859d66;color:#f4faff}.visual-index{color:#76a4be;font:11px/1.6 ui-monospace,SFMono-Regular,Consolas,monospace;flex-shrink:0}.visual-node strong{display:block;font-size:14px;line-height:1.5;font-weight:600;color:#24485f}.lecture-slide-dark .visual-node strong{color:#f1faff}.visual-node em{display:block;font-style:normal;font-size:20px;font-variant-numeric:tabular-nums;color:#18699c}.visual-node p{font-size:11px;line-height:1.65;color:#718da0;margin:4px 0 0}.lecture-slide-dark .visual-node p{color:#afccdd}.slide-visual-metric{grid-template-columns:repeat(2,minmax(0,1fr))}.slide-visual-metric .visual-node{min-height:96px;flex-direction:column;gap:3px}.slide-visual-metric .visual-index{font-size:9px}.slide-visual-metric .visual-node strong{font-size:19px}.slide-visual-cards{grid-template-columns:repeat(2,minmax(0,1fr))}.slide-visual-cards .visual-node{min-height:85px}.slide-visual-cards .visual-node:first-child:last-child{grid-column:span 2}.slide-visual-compare{grid-template-columns:repeat(2,minmax(0,1fr))}.slide-visual-compare .visual-node{min-height:130px;align-items:center}.slide-table-wrap{overflow:auto;max-width:100%;max-height:320px;border-radius:10px;border:1px solid #d6e7f1;background:#fff}.slide-table-wrap table{font-size:12px;width:100%;white-space:normal}.slide-table-wrap th,.slide-table-wrap td{padding:9px 11px}.slide-page-number{position:absolute;right:44px;bottom:23px;font:11px ui-monospace,SFMono-Regular,Consolas,monospace;letter-spacing:1px;color:#7395aa}.slides-controls{display:flex;align-items:center;gap:12px;min-height:67px;padding:14px 23px;border-top:1px solid #e0eaf1}.slides-prev,.slides-next{width:37px;height:37px;display:grid;place-items:center;border:1px solid #d6e5ef;border-radius:9px;background:white;color:#2f6587;font-size:20px;line-height:1}.slides-prev:hover:not(:disabled),.slides-next:hover:not(:disabled){background:#e5f3fb}.slides-prev:disabled,.slides-next:disabled{opacity:.42;cursor:default}.slides-counter{min-width:51px;text-align:center;color:#527d97;font:12px ui-monospace,SFMono-Regular,Consolas,monospace}.slides-dots{display:flex;align-items:center;gap:6px;margin-left:5px}.slides-dots button{width:6px;height:6px;border:0;border-radius:50%;padding:0;background:#c7d9e5;transition:width .2s,background .2s}.slides-dots button[aria-current=true]{width:18px;border-radius:5px;background:#3c8cbb}.slides-hint{margin-left:auto;color:#8aa1b1;font-size:11px}.slides-launch{margin-left:auto;font-size:13px;font-weight:600}.slides-launch span{font-size:11px;color:#8aa2b2;font-weight:400;margin-left:6px}.lesson-slides:fullscreen{display:flex;flex-direction:column;border:0;border-radius:0;margin:0;background:#eaf5fb}.lesson-slides:fullscreen .slide-viewport{flex:1;display:flex}.lesson-slides:fullscreen .slide-track{width:100%}.lesson-slides:fullscreen .lecture-slide,.lesson-slides:fullscreen .slide-grid{min-height:100%}.lesson-slides:fullscreen .slide-grid{padding:6vh 7vw}.lesson-slides:fullscreen .lecture-slide h3{font-size:clamp(35px,4vw,65px)}.lesson-slides:fullscreen .slide-lead{font-size:clamp(18px,1.65vw,27px)}.lesson-slides:fullscreen .slide-points{font-size:clamp(16px,1.2vw,21px)}
/* Enterprise examples remain in the chapter narrative, with an explanatory diagram. */
.enterprise-case{margin:27px 0 37px;border:1px solid #d7e7f0;border-radius:16px;background:linear-gradient(145deg,#f4faff,#eef7fc);padding:25px 28px;color:#25485e}.case-topline{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:17px}.case-type{font-size:11px;letter-spacing:1px;color:#407eaa}.case-org{font-size:12px;color:#5a849c;font-weight:600}.case-context{font-size:15px;line-height:1.8;margin:0 0 21px!important;color:#395b70}.case-flow{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:9px;position:relative}.case-step{min-width:0;padding:14px 12px;border:1px solid #d8e7ef;border-radius:9px;background:#fff}.case-step-number{display:block;color:#94b1c3;font:10px/1.5 ui-monospace,SFMono-Regular,Consolas,monospace}.case-step strong{display:block;font-size:13px;color:#34749a;margin:7px 0 4px}.case-step p{font-size:11px;line-height:1.65;margin:0!important;color:#526f81}.case-takeaway{display:grid;grid-template-columns:auto 1fr;gap:12px;margin-top:18px;padding:13px 16px;background:#dfeff8;border-radius:9px}.case-takeaway span{font-size:11px;white-space:nowrap;color:#4983a6;padding-top:3px}.case-takeaway strong{font-size:13px;line-height:1.7;color:#244e68;font-weight:600}.case-evidence{font-size:11px;color:#6d899a;margin-top:15px}.case-evidence summary{cursor:pointer}.case-evidence p{font-size:11px!important;line-height:1.75;margin:8px 0 0!important}.case-evidence a{font-size:11px}
/* Full-width vector diagrams; the enlargement button is useful on phones. */
.prose figure{border:1px solid #e2ebf1;border-radius:14px;background:#fbfdff;padding:15px 17px 18px}.prose figure img{display:block;width:100%;max-width:1100px;height:auto;margin:9px auto 13px}.figure-toolbar{display:flex;justify-content:space-between;align-items:center;color:#8299a8;font-size:11px}.figure-toolbar button{background:transparent;border:0;color:#317ca9;font-size:11px;padding:3px 6px}.figure-toolbar button:hover{text-decoration:underline}.figure-dialog{position:fixed;width:min(94vw,1500px);max-width:none;max-height:91vh;border:1px solid #d5e5ef;border-radius:16px;padding:48px 20px 20px;background:#fafdff;box-shadow:0 40px 100px #07182755}.figure-dialog::backdrop{background:#0e2235b9;backdrop-filter:blur(3px)}.figure-dialog-close{position:absolute;right:13px;top:7px;border:0;background:transparent;color:#35566d;font-size:27px}.figure-dialog-scroller{width:100%;max-height:72vh;overflow:auto}.figure-dialog-scroller img{display:block;width:100%;min-width:1050px;height:auto}.figure-dialog-caption{text-align:center;color:#5d788a;font-size:13px;line-height:1.6;margin:12px 0 0}
@media(max-width:1100px){.slide-grid{padding:40px 34px 55px;gap:19px}.lecture-slide h3{font-size:29px}.slide-lead{font-size:14px}.slide-points{font-size:12px}.visual-node strong{font-size:12px}.visual-node p{font-size:10px}}
@media(max-width:760px){.lesson-slides{margin:18px 0 44px;border-radius:15px}.slides-toolbar{padding:14px 17px;min-height:65px}.slides-toolbar strong{font-size:13px}.slides-fullscreen{font-size:10px;padding:6px 8px}.lecture-slide,.slide-grid{min-height:590px}.slide-grid{display:flex;flex-direction:column;align-items:stretch;justify-content:flex-start;gap:23px;padding:34px 25px 48px}.lecture-slide h3{font-size:28px;margin-bottom:13px}.slide-kicker{font-size:10px;margin-bottom:14px}.slide-lead{font-size:14px;line-height:1.7;margin-bottom:14px}.slide-points{font-size:12px;gap:6px}.slide-art{flex:1;align-content:start}.slide-visual-content{gap:8px}.slide-visual-flow{grid-template-columns:repeat(2,minmax(0,1fr))}.visual-node{padding:10px!important}.visual-node p{font-size:10px}.slide-page-number{right:20px;bottom:17px}.slides-controls{padding:11px 14px;gap:9px}.slides-prev,.slides-next{width:34px;height:34px}.slides-hint{display:none}.slides-dots{margin-left:auto;gap:4px}.slides-dots button{width:5px;height:5px}.slides-dots button[aria-current=true]{width:13px}.enterprise-case{padding:19px 17px;border-radius:12px}.case-context{font-size:13px}.case-flow{grid-template-columns:repeat(2,minmax(0,1fr))}.case-step{padding:12px 10px}.case-step strong{font-size:12px}.case-step p{font-size:10px}.case-takeaway{display:block}.case-takeaway strong{display:block;margin-top:4px;font-size:12px}.prose figure{padding:10px}.figure-dialog{width:96vw;padding:44px 10px 15px}.figure-dialog-scroller img{min-width:950px}}
@media(max-width:420px){.slide-grid{padding-inline:20px;min-height:620px}.slide-visual-cards,.slide-visual-compare{grid-template-columns:repeat(2,minmax(0,1fr))}.visual-node strong{font-size:11px}.slide-table-wrap{max-height:240px}}
@media(prefers-reduced-motion:reduce){.slide-track,.slides-dots button{transition:none}}
@media print{.lesson-slides,.figure-toolbar,.figure-dialog{display:none!important}.enterprise-case{break-inside:avoid}.prose figure{border:0}}
/* Keep slide headings legible against the dark opening and closing panels. */
.lecture-slide.lecture-slide-dark h3{color:#f3f9ff}
@media(max-width:760px){
  .lecture-slide:first-child .slide-art:before{inset:0 -10px -22px;opacity:.10}
  .prose figure{overflow-x:auto;overscroll-behavior-inline:contain}
  .prose figure img{min-width:700px;max-width:none}
  .figure-toolbar span::after{content:" · 左右滑动查看"}
}
/* Complete, readable problem statements sit immediately above editable code. */
.challenge-card{margin:25px 0 23px;padding:27px 29px;border:1px solid #d6e7f1;border-radius:16px;background:linear-gradient(145deg,#f6fbfe,#edf7fc);color:#2b4c60}.challenge-heading{display:flex;align-items:center;gap:15px;padding-bottom:17px;border-bottom:1px solid #dbeaf3}.challenge-heading span{font-size:11px;color:#4785aa;letter-spacing:1px;white-space:nowrap}.challenge-heading strong{font-size:20px;font-weight:600;color:#1c4159}.challenge-background{padding:17px 0 12px}.challenge-background span,.challenge-bottom span{display:block;font-size:11px;font-weight:650;letter-spacing:.5px;color:#4884a9}.challenge-card p{font-size:14px;line-height:1.8;color:#49697b;margin:7px 0 0}.challenge-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.challenge-grid>div{padding:17px 18px;border:1px solid #e1edf5;border-radius:10px;background:#fff}.challenge-grid h2{font-size:13px;line-height:1.5;color:#2572a0;margin:0;padding:0;border:0}.challenge-grid p{font-size:12px;margin-top:7px}.challenge-bottom{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin-top:18px;padding-top:16px;border-top:1px solid #dbeaf3}.challenge-bottom p{font-size:12px}.program-guide{margin:24px 0;padding:14px 19px;border-left:3px solid #86b7d4;border-radius:0 10px 10px 0;background:#f0f8fc}.program-guide strong{font-size:12px;color:#317ca8}.program-guide p{font-size:13px;line-height:1.75;color:#506e80;margin:5px 0 0}
@media(max-width:760px){.challenge-card{padding:20px 18px}.challenge-heading{align-items:flex-start;flex-direction:column;gap:5px}.challenge-heading strong{font-size:18px}.challenge-background{padding-top:14px}.challenge-card p{font-size:13px}.challenge-grid{grid-template-columns:1fr}.challenge-grid>div{padding:13px 15px}.challenge-bottom{grid-template-columns:1fr;gap:13px}.challenge-bottom p{font-size:12px}}