/* Editorial exercise plate. All color comes from the platform's design tokens. */
.xi-detail{--xi-accent:var(--live);--xi-soft:var(--live-soft);display:grid;gap:24px;min-width:0;padding-bottom:32px;color:var(--ink)}
.xi-family-decision_branches,.xi-family-file_flow{--xi-accent:var(--warning-text);--xi-soft:var(--warning-soft)}
.xi-family-iteration_pattern,.xi-family-module_function{--xi-accent:var(--question-live-text);--xi-soft:var(--question-live-soft)}
.xi-family-string_text,.xi-family-array_1d{--xi-accent:var(--progress-text);--xi-soft:var(--progress-soft)}
.xi-family-sort_search{--xi-accent:var(--question-live-text);--xi-soft:var(--question-live-soft)}
.xi-family-record_fields{--xi-accent:var(--success-text);--xi-soft:var(--success-soft)}
.xi-family-matrix_grid{--xi-accent:var(--network-text);--xi-soft:var(--network-soft)}
.xi-back{display:inline-flex;align-items:center;min-height:var(--tap);width:max-content;color:var(--live-text);font-weight:700;text-decoration:none}
.xi-back:hover{text-decoration:underline}
.xi-hero{display:grid;grid-template-columns:170px minmax(0,1fr);min-width:0;overflow:hidden;border-radius:var(--r-lg);background:linear-gradient(135deg,var(--navy),var(--ink-900));color:var(--ink-inverse);box-shadow:var(--shadow-2)}
.xi-folio{display:flex;flex-direction:column;align-items:flex-start;justify-content:center;padding:24px 20px 24px 28px;border-right:1px solid var(--slate-600);font-family:var(--font-mono)}
.xi-folio span{font-size:12px;letter-spacing:.12em;font-weight:700;color:var(--teal-100)}
.xi-folio strong{font-size:clamp(66px,8vw,104px);line-height:1;letter-spacing:-.1em;font-weight:700;font-variant-numeric:tabular-nums;color:var(--paper)}
.xi-folio small{margin-top:8px;font-size:12px;color:var(--slate-300)}
.xi-hero-content{min-width:0;padding:30px 36px 32px}
.xi-overline{display:flex;gap:12px;align-items:center;margin:0 0 10px;color:var(--teal-100);font-size:12px;line-height:1.5;font-weight:800;letter-spacing:.08em;text-transform:uppercase}
.xi-overline span{color:var(--slate-400)}
.xi-hero h1{max-width:20ch;margin:0;font-size:clamp(32px,4vw,54px);font-weight:820;line-height:1.04;letter-spacing:-.045em;text-wrap:balance}
.xi-meta{display:flex;gap:8px;flex-wrap:wrap;margin-top:20px}.xi-meta span{display:inline-flex;align-items:center;min-height:30px;padding:4px 10px;border:1px solid var(--slate-500);border-radius:var(--r-pill);font-size:12px;font-weight:700;color:var(--paper)}
.xi-skill-list{display:flex;gap:8px;flex-wrap:wrap;margin-top:20px}.xi-skill{display:inline-flex;padding:6px 10px;border-radius:var(--r-xs);background:var(--slate-100);color:var(--navy);font-size:12px;font-weight:750;line-height:1.35}
.xi-review-note{margin:10px 0 0;color:var(--slate-300);font-size:12px;line-height:1.5}
.xi-prompt{display:grid;gap:8px;min-width:0;padding:30px 34px;border-left:6px solid var(--xi-accent);border-radius:0 var(--r-lg) var(--r-lg) 0;background:var(--paper);box-shadow:var(--shadow-1)}
.xi-section-label{color:var(--xi-accent);font-size:12px;line-height:1.4;font-weight:850;letter-spacing:.11em;text-transform:uppercase}
.xi-prompt h2{max-width:54ch;margin:0;font-size:clamp(23px,2.9vw,36px);line-height:1.25;letter-spacing:-.025em;text-wrap:pretty;overflow-wrap:anywhere}
.xi-context{max-width:75ch;margin:8px 0 0;color:var(--ink-2);font-size:16px;line-height:1.6;white-space:pre-wrap}
.xi-board{display:grid;grid-template-columns:minmax(0,1.6fr) minmax(255px,.7fr);gap:0;min-width:0;overflow:hidden;border:1px solid var(--line);border-radius:var(--r-lg);background:var(--paper);box-shadow:var(--shadow-1)}
.xi-board--solo{grid-template-columns:1fr}
.xi-board-heading{grid-column:1/-1;display:flex;align-items:center;gap:12px;min-height:58px;padding:12px 24px;border-bottom:1px solid var(--line);background:var(--xi-soft)}
.xi-board-heading p{margin:0;color:var(--ink-800);font-size:14px;font-weight:800}
.xi-board-rule{width:30px;height:4px;border-radius:var(--r-pill);background:var(--xi-accent)}
.xi-visual{display:grid;grid-template-rows:auto minmax(0,1fr) auto;min-width:0;margin:0;padding:18px;background:var(--paper)}
.xi-visual-top{display:flex;justify-content:space-between;gap:12px;margin:0 0 12px;color:var(--muted);font-size:11px;font-weight:750;letter-spacing:.07em;text-transform:uppercase}
.xi-visual-frame{display:grid;place-items:center;min-width:0;overflow:hidden;border:1px solid var(--line);border-radius:var(--r-md);background:var(--bg-sunken)}
.xi-visual-frame img{display:block;width:100%;height:auto;max-height:580px;object-fit:contain}
.xi-visual-missing{padding:64px 20px;color:var(--muted);text-align:center}
.xi-visual figcaption{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:44px;color:var(--muted);font-size:12px;line-height:1.4}
.xi-zoom{appearance:none;min-height:36px;padding:4px 10px;border:1px solid var(--line-strong);border-radius:var(--r-sm);background:var(--paper);color:var(--xi-accent);font:inherit;font-size:12px;font-weight:800;cursor:pointer}
.xi-zoom:hover{background:var(--xi-soft)}
.xi-facts{display:flex;flex-direction:column;gap:12px;min-width:0;padding:18px;border-left:1px solid var(--line);background:var(--slate-50)}
.xi-fact{display:grid;grid-template-columns:34px minmax(0,1fr);gap:12px;min-width:0;padding:20px 16px;border:1px solid var(--line);border-radius:var(--r-md);background:var(--paper)}
.xi-fact-index{display:grid;place-items:center;width:34px;height:34px;border-radius:var(--r-xs);background:var(--xi-soft);color:var(--xi-accent);font-family:var(--font-mono);font-size:20px;font-weight:800}
.xi-fact h3{margin:2px 0 8px;color:var(--xi-accent);font-size:12px;line-height:1.35;letter-spacing:.04em;text-transform:uppercase}
.xi-fact p{margin:0;font-size:clamp(15px,1.6vw,19px);line-height:1.5;font-weight:650;overflow-wrap:anywhere;white-space:pre-wrap}
.xi-candidate-note{display:block;margin-top:10px;color:var(--warning-text);font-size:12px;line-height:1.4;font-weight:750}
.xi-fact--candidate{border-style:dashed}
.xi-support{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(240px,.7fr);gap:16px;min-width:0}
.xi-support--single{grid-template-columns:1fr}
.xi-support:empty{display:none}
.xi-example,.xi-support>.xi-fact{min-width:0;padding:24px;border:1px solid var(--line);border-radius:var(--r-lg);background:var(--paper);box-shadow:var(--shadow-1)}
.xi-example{display:grid;gap:14px}.xi-example-pair{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
.xi-example-cases{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.xi-example-case{padding:16px;border:1px solid var(--line);border-radius:var(--r-md)}.xi-example-case .xi-example-pair>div{padding:12px}.xi-example h4{margin:0 0 8px;color:var(--xi-accent);font-size:12px;font-weight:800}
.xi-example-pair>div{min-width:0;padding:18px;border-radius:var(--r-md);background:var(--xi-soft)}
.xi-example h3{margin:0 0 12px;color:var(--xi-accent);font-size:13px;font-weight:800}
.xi-example pre{max-width:100%;margin:0;white-space:pre-wrap;overflow-wrap:anywhere;font:13px/1.65 var(--font-mono)}
.xi-support>.xi-fact{grid-template-columns:34px minmax(0,1fr);align-content:start;background:var(--warning-soft)}
.xi-support>.xi-fact h3{color:var(--warning-text)}
.xi-action-dock{display:flex;align-items:center;gap:12px;flex-wrap:wrap;padding:18px 20px;border:1px solid var(--line);border-radius:var(--r-lg);background:var(--paper);box-shadow:var(--shadow-1)}
.xi-action-dock .btn.primary{min-height:50px;padding-inline:22px}.xi-action-dock .xl-note{margin-left:auto}
.xi-image-dialog{width:min(1100px,96vw);max-width:96vw;max-height:94vh;padding:0;border:0;border-radius:var(--r-lg);background:var(--paper);color:var(--ink);box-shadow:var(--shadow-3)}
.xi-image-dialog::backdrop{background:var(--ink-900);opacity:.76}.xi-image-dialog-head{position:sticky;top:0;display:flex;align-items:center;justify-content:space-between;gap:12px;padding:14px 18px;border-bottom:1px solid var(--line);background:var(--paper)}
.xi-image-dialog-head strong{font-size:14px}.xi-image-dialog-head button{min-height:var(--tap);padding:8px 14px;border:1px solid var(--line-strong);border-radius:var(--r-sm);background:var(--paper);color:var(--ink);font:inherit;font-weight:700;cursor:pointer}
.xi-image-dialog img{display:block;width:100%;height:auto}.xi-image-dialog[open]{overflow:auto}
.xi-detail .xl-neighbors{display:grid;grid-template-columns:repeat(2,minmax(0,1fr))}
/* Native sheet (exercise-fiche-v1): hero, infographic statement, sticky actions. */
.xi-detail--sheet{gap:18px}
.xi-detail--sheet .xi-hero{grid-template-columns:112px minmax(0,1fr)}
.xi-detail--sheet .xi-folio{padding:16px 18px}.xi-detail--sheet .xi-folio strong{font-size:clamp(46px,6vw,66px)}
.xi-detail--sheet .xi-hero-content{display:grid;align-content:center;gap:12px;padding:20px 26px}
.xi-detail--sheet .xi-hero h1{max-width:none;font-size:clamp(27px,3.2vw,42px)}
.xi-detail--sheet .xi-meta{margin-top:0}
.xi-detail--sheet .xi-meta span{min-height:28px;font-size:13px;font-weight:650;border-color:var(--slate-500)}
.xi-preparing{display:grid;gap:8px;padding:28px;border:1px dashed var(--line-strong);border-radius:var(--r-lg);background:var(--paper)}
.xi-preparing h2{margin:0;font-size:22px}.xi-preparing p{margin:0;max-width:60ch;color:var(--ink-2);line-height:1.6}
.xi-action-dock--sticky{position:sticky;bottom:0;z-index:5;justify-content:flex-start}
.xi-action-dock--sticky .btn{min-height:var(--tap)}
.xi-solution-lock{display:inline-flex;align-items:center;gap:8px;color:var(--ink-2);font-size:14px;line-height:1.4}
.xi-solution-lock svg{width:18px;height:18px;flex:none;color:var(--muted)}
@media(max-width:620px){
 .xi-detail--sheet .xi-hero{grid-template-columns:1fr}.xi-detail--sheet .xi-folio{flex-direction:row;align-items:baseline;gap:8px;padding:12px 16px;border-right:0;border-bottom:1px solid var(--slate-600)}
 .xi-detail--sheet .xi-folio strong{font-size:34px;letter-spacing:-.04em}.xi-detail--sheet .xi-folio small{margin:0}.xi-detail--sheet .xi-hero-content{padding:16px}
 .xi-action-dock--sticky{margin-inline:-4px;padding:10px 12px calc(10px + env(safe-area-inset-bottom));border-radius:var(--r-md) var(--r-md) 0 0;box-shadow:0 -8px 24px -12px rgba(16,33,58,.28)}
 .xi-action-dock--sticky .btn{flex:1 1 auto}
}
/* R4: one source-complete visual reading composition, with no raw-PDF panel. */
.xi-detail--r4{gap:18px}
.xi-detail--r4 .xi-hero{grid-template-columns:116px minmax(0,1fr)}
.xi-detail--r4 .xi-folio{padding:16px 18px}
.xi-detail--r4 .xi-folio strong{font-size:clamp(48px,6vw,70px)}
.xi-detail--r4 .xi-hero-content{padding:21px 26px}
.xi-detail--r4 .xi-hero h1{max-width:none;font-size:clamp(27px,3vw,40px)}
.xi-detail--r4 .xi-meta,.xi-detail--r4 .xi-skill-list{margin-top:11px}
.xi-composition{display:grid;grid-template-columns:minmax(250px,.8fr) minmax(0,1.45fr);gap:0;min-width:0;overflow:hidden;border:1px solid var(--line);border-radius:var(--r-lg);background:var(--paper);box-shadow:var(--shadow-1)}
.xi-composition-intro{min-width:0;padding:27px 28px;border-right:1px solid var(--line);border-top:5px solid var(--xi-accent);background:var(--xi-soft)}
.xi-composition-intro h2{margin:16px 0 0;color:var(--ink);font-size:clamp(20px,2.15vw,29px);line-height:1.3;letter-spacing:-.025em;overflow-wrap:anywhere;white-space:pre-wrap}
.xi-detail--r4 .xi-visual{grid-column:2;margin:0;padding:17px 18px 10px}
.xi-detail--r4 .xi-composition .xi-visual{grid-column:2;grid-row:1}
.xi-detail--r4 .xi-visual-frame{border:0;background:var(--paper)}
.xi-detail--r4 .xi-visual-frame img{max-height:560px}
.xi-detail--r4 .xi-visual figcaption{justify-content:flex-end;min-height:38px}
.xi-story-grid{display:grid;grid-column:1/-1;grid-template-columns:repeat(2,minmax(0,1fr));gap:0;padding:8px 24px 16px;border-top:1px solid var(--line)}
.xi-detail--r4 .xi-composition .xi-story-grid{grid-row:2}
.xi-balanced-mobile{display:none}
.xi-story{min-width:0;margin:0;padding:18px 18px 15px;border-bottom:1px solid var(--line);border-left:3px solid transparent}
.xi-story--task{border-left-color:var(--xi-accent)}
.xi-story--rule{border-left-color:var(--warning)}
.xi-story--example{grid-column:1/-1;border-left-color:var(--progress)}
.xi-story--table{grid-column:1/-1;border-left-color:var(--xi-accent)}
.xi-story h3{margin:0 0 8px;color:var(--xi-accent);font-size:12px;line-height:1.3;font-weight:850;letter-spacing:.08em;text-transform:uppercase}
.xi-story p{margin:0;color:var(--ink-2);font-size:15px;line-height:1.65;overflow-wrap:anywhere;white-space:pre-wrap}
.xi-table-scroll{max-width:100%;overflow-x:auto}
.xi-story--table table{width:100%;border-collapse:collapse;table-layout:fixed;color:var(--ink-2);font-size:15px;line-height:1.45}
.xi-story--table th,.xi-story--table td{padding:10px 12px;text-align:left;vertical-align:top;border:1px solid var(--line);overflow-wrap:anywhere}
.xi-story--table th{color:var(--ink);background:var(--xi-soft);font-weight:800}
.xi-story--table tr:nth-child(even) td{background:var(--paper)}
.xi-story--grouped>p+p{margin-top:10px;padding-top:10px;border-top:1px solid var(--line)}
.xi-story--grouped>.xi-story-example+.xi-story-example,.xi-story--grouped>p+.xi-story-example,.xi-story--grouped>.xi-story-example+p{margin-top:12px}
.xi-story-example{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0;border-top:1px solid var(--line)}
.xi-story-examples .xi-story-example+.xi-story-example{margin-top:12px}
.xi-story-example>div{padding:12px 18px 8px}
.xi-story-example>div+div{border-left:1px solid var(--line)}
.xi-story-example p{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:13px;line-height:1.55;font-variant-numeric:tabular-nums;white-space:pre-wrap}
.xi-story-example small{display:block;margin-bottom:5px;color:var(--muted);font-size:11px;font-weight:800;text-transform:uppercase;letter-spacing:.06em}
.xi-family-matrix_grid .xi-story-grid,.xi-family-record_fields .xi-story-grid,.xi-family-file_flow .xi-story-grid{grid-template-columns:repeat(3,minmax(0,1fr))}
.xi-family-matrix_grid .xi-story--example,.xi-family-record_fields .xi-story--example,.xi-family-file_flow .xi-story--example{grid-column:span 2}
.xi-detail--r4[data-xi-variant^="text_"] .xi-composition-intro{background:var(--progress-soft)}
.xi-detail--r4[data-xi-variant^="branch_scale"] .xi-composition-intro{background:var(--warning-soft)}
.xi-detail--r4[data-xi-variant^="matrix_"] .xi-composition-intro{background:var(--network-soft)}
/* The reading path changes with the material, not only with accent color. */
.xi-family-decision_branches .xi-board,.xi-family-iteration_pattern .xi-board,.xi-family-string_text .xi-board,.xi-family-sort_search .xi-board{grid-template-columns:1fr}
.xi-family-decision_branches .xi-facts,.xi-family-iteration_pattern .xi-facts,.xi-family-string_text .xi-facts,.xi-family-sort_search .xi-facts{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));border-left:0;border-top:1px solid var(--line)}
.xi-family-decision_branches .xi-board-heading,.xi-family-file_flow .xi-board-heading{background:var(--warning-soft)}
.xi-family-module_function .xi-visual,.xi-family-record_fields .xi-visual,.xi-family-file_flow .xi-visual{grid-column:2;grid-row:2}
.xi-family-module_function .xi-facts,.xi-family-record_fields .xi-facts,.xi-family-file_flow .xi-facts{grid-column:1;grid-row:2;border-left:0;border-right:1px solid var(--line)}
.xi-family-record_fields .xi-board,.xi-family-file_flow .xi-board{grid-template-columns:minmax(260px,.7fr) minmax(0,1.6fr)}
.xi-family-matrix_grid .xi-visual-frame{background:var(--network-soft)}
.xi-family-string_text .xi-visual-frame{background:var(--progress-soft)}
.xi-family-array_1d .xi-board-heading{border-left:4px solid var(--xi-accent)}
.xi-family-sort_search .xi-visual-frame{background:var(--question-live-soft)}
.xi-family-calculation_geometry .xi-board-heading{border-top:4px solid var(--xi-accent)}
.xi-family-file_flow .xi-fact-index{border-radius:2px}
.xi-detail .xi-board--solo{grid-template-columns:1fr}.xi-detail .xi-board--solo .xi-visual{grid-column:1;grid-row:2}
@media(max-width:800px){
 .xi-composition{grid-template-columns:1fr}.xi-composition-intro{border-right:0;border-bottom:1px solid var(--line)}.xi-detail--r4 .xi-composition .xi-visual{grid-column:1;grid-row:2}.xi-detail--r4 .xi-composition .xi-story-grid{grid-row:3}
 .xi-hero{grid-template-columns:125px minmax(0,1fr)}.xi-folio{padding:20px}.xi-hero-content{padding:24px}.xi-board,.xi-family-record_fields .xi-board,.xi-family-file_flow .xi-board{grid-template-columns:1fr}
 .xi-visual,.xi-family-module_function .xi-visual,.xi-family-record_fields .xi-visual,.xi-family-file_flow .xi-visual{grid-column:1;grid-row:2}
 .xi-facts,.xi-family-module_function .xi-facts,.xi-family-record_fields .xi-facts,.xi-family-file_flow .xi-facts{grid-column:1;grid-row:3;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));border-left:0;border-right:0;border-top:1px solid var(--line)}
 .xi-support{grid-template-columns:1fr}
}
@media(max-width:620px){
 .xi-detail--r4 .xi-visual-frame:has(.xi-balanced-mobile)>img{display:none}.xi-balanced-mobile{display:block;padding:13px 2px 5px}.xi-balanced-rule{margin:0 0 12px;font-size:14px;line-height:1.5}.xi-balanced-cases{display:grid;gap:10px}.xi-balanced-cases section{padding:14px;border:1px solid var(--line);border-radius:9px;background:var(--paper)}.xi-balanced-cases section:first-child{background:var(--progress-soft)}.xi-balanced-cases section:last-child{background:var(--warning-soft)}.xi-balanced-cases h3{margin:0 0 10px;font-size:18px}.xi-balanced-cases p{margin:10px 0;font-size:17px;line-height:1.55;font-weight:750}.xi-balanced-cases strong{font-size:15px}.xi-balanced-digits{display:flex;align-items:center;gap:5px}.xi-balanced-digits span{display:grid;place-items:center;min-width:40px;height:44px;border:1px solid var(--xi-accent);border-radius:6px;background:#fff;font-weight:850;font-size:21px}.xi-balanced-digits b{margin:0 2px;color:var(--xi-accent)}
 .xi-detail--r4 .xi-hero{grid-template-columns:1fr}.xi-detail--r4 .xi-folio{padding:12px 16px}.xi-detail--r4 .xi-folio strong{font-size:34px}.xi-detail--r4 .xi-hero-content{padding:17px 16px}.xi-composition-intro{padding:20px 17px}.xi-composition-intro h2{font-size:22px}.xi-story-grid,.xi-family-matrix_grid .xi-story-grid,.xi-family-record_fields .xi-story-grid,.xi-family-file_flow .xi-story-grid{grid-template-columns:1fr;padding:4px 12px 12px}.xi-story--example,.xi-family-matrix_grid .xi-story--example,.xi-family-record_fields .xi-story--example,.xi-family-file_flow .xi-story--example{grid-column:1}.xi-story{padding:16px 10px}.xi-story-example{grid-template-columns:1fr}.xi-story-example>div+div{border-left:0;border-top:1px solid var(--line)}
 .xi-detail{gap:16px}.xi-hero{grid-template-columns:1fr}.xi-folio{display:flex;flex-direction:row;align-items:baseline;justify-content:flex-start;gap:10px;padding:14px 18px;border-right:0;border-bottom:1px solid var(--slate-600)}.xi-folio strong{font-size:34px;letter-spacing:-.04em}.xi-folio small{margin:0}.xi-hero-content{padding:22px 18px 24px}.xi-hero h1{font-size:clamp(29px,8vw,38px)}
 .xi-overline{flex-wrap:wrap;font-size:11px}.xi-skill-list{margin-top:16px}.xi-prompt{padding:22px 18px}.xi-prompt h2{font-size:clamp(22px,6vw,28px)}
 .xi-board-heading{padding-inline:16px}.xi-visual{padding:10px}.xi-visual-top{padding:4px 4px 0}.xi-visual figcaption{padding:0 4px}.xi-facts,.xi-family-decision_branches .xi-facts,.xi-family-iteration_pattern .xi-facts,.xi-family-string_text .xi-facts,.xi-family-sort_search .xi-facts{grid-template-columns:1fr;padding:12px}
 .xi-fact{padding:16px}.xi-example,.xi-support>.xi-fact{padding:18px}.xi-example-pair,.xi-example-cases{grid-template-columns:1fr}.xi-action-dock{padding:14px}.xi-action-dock .btn{width:100%}.xi-action-dock .xl-note{margin-left:0}
 .xi-detail .xl-neighbors{grid-template-columns:1fr}.xi-detail .xl-neighbors a:last-child{grid-column:1;text-align:left}
 .xi-image-dialog img{min-width:720px}.xi-image-dialog-head{position:sticky;left:0;min-width:720px}
}