/* Shared chrome uses ph-* names so exercises keep their own selectors. */
:root{--ph-ink:#172335;--ph-secondary:#4c5d74;--ph-blue:#065edb;--ph-accent-gradient:linear-gradient(110deg,#0868d8 5%,#4b57db 58%,#7652c7 100%);--ph-system:-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}
.ph-shell,.ph-shell *{box-sizing:border-box}
.ph-shell{font-family:var(--ph-system);font-size:14px;line-height:1.5;color:var(--ph-ink);letter-spacing:normal;text-transform:none;text-shadow:none}
.ph-shell a{color:inherit;text-decoration:none;font:inherit;letter-spacing:inherit;text-shadow:none;border:0;background:none}
.ph-shell a:hover{color:var(--ph-blue)}
.ph-shell a:focus-visible,.ph-shell button:focus-visible{outline:3px solid #064eb9;outline-offset:4px}
.domain-accent{color:var(--ph-blue)}
@supports (background-clip:text) or (-webkit-background-clip:text){.domain-accent{background-image:var(--ph-accent-gradient);background-clip:text;-webkit-background-clip:text;color:transparent}}
@media(forced-colors:active){.domain-accent{background:none;color:LinkText}}
.ph-footer{display:flex;position:relative;z-index:1;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:16px;width:min(1120px,calc(100% - 64px));padding:28px 0 32px;margin:30px auto 0;border-top:1px solid #cad8e7;background:transparent;color:var(--ph-secondary);font-size:13px}
.ph-footer .ph-brand{font-size:21px;font-weight:700;letter-spacing:-1px;white-space:nowrap;line-height:1.2}
.ph-footer-links{display:flex;flex-wrap:wrap;gap:20px;align-items:center}
.ph-landing>main{position:relative;z-index:1}
.document-hidden .motion{animation-play-state:paused}
.ph-trap{position:absolute!important;left:-10000px!important;width:1px;height:1px;overflow:hidden}
.field small{color:#52627a;font-size:12px;line-height:1.5}
.contact-form button:disabled{opacity:.68;transform:none;cursor:default}
.contact-form [aria-invalid="true"]{border-color:#b82c3f}
.contact-form .form-status[data-error="true"]{color:#9e2639}
.ph-page{padding-top:68px;padding-bottom:60px;min-height:70vh}
.ph-page .ph-back{display:inline-flex;align-items:center;min-height:44px;font-size:14px;color:#0757c2;margin-bottom:20px}
.ph-page h1{font-size:clamp(36px,6.3vw,72px);letter-spacing:-.055em;white-space:normal;max-width:1000px;text-wrap:balance}
.ph-page>.section-intro{margin-top:22px;max-width:750px;font-size:20px}
/* Learning overviews: one glass surface per group, compact linked rows. */
.ph-catalog{max-width:1040px;padding-top:28px}
.ph-category-links{display:flex;gap:28px;overflow-x:auto;overscroll-behavior-x:contain;max-width:100%;margin:0 0 38px;padding:3px 3px 0;border-bottom:1px solid #dce2eb;scrollbar-width:thin}
.ph-category-links a{position:relative;display:flex;flex:none;align-items:center;min-height:46px;padding:8px 0 13px;color:#58677b;font-size:14px;font-weight:500;white-space:nowrap}
.ph-category-links a[aria-current]{color:#0757c2;font-weight:650}
.ph-category-links a[aria-current]::after{content:"";position:absolute;bottom:0;left:0;right:0;height:2px;border-radius:2px;background:var(--ph-accent-gradient)}
.ph-category-links a:focus-visible{outline-offset:-3px;border-radius:4px}
.ph-catalog-intro{max-width:680px;margin-bottom:26px}
.ph-catalog h1{font-size:clamp(32px,5vw,58px);line-height:1.08;letter-spacing:-.05em;text-wrap:initial}
.ph-catalog .section-intro{font-size:17px;line-height:1.55;margin:14px 0 0;max-width:600px;letter-spacing:-.15px}
.ph-catalog-toolbar{display:flex;align-items:center;justify-content:space-between;gap:16px;margin:0 0 30px}
.ph-sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.ph-search{position:relative;flex:1;max-width:420px;min-width:0}
.ph-search>svg{position:absolute;left:15px;top:50%;transform:translateY(-50%);width:18px;height:18px;fill:none;stroke:#65758b;stroke-width:2;stroke-linecap:round;pointer-events:none}
.ph-search input{min-height:46px;padding:11px 13px 11px 43px;border:1px solid #c5cedb;border-radius:14px;background:#ffffffa8;box-shadow:inset 0 1px 1px #fff;font-size:16px;line-height:1.4}
.ph-search input::placeholder{color:#607087;opacity:1}
.ph-result-count{flex:none;margin:0;font-size:13px;line-height:1.5;color:#58677b;font-variant-numeric:tabular-nums}
.ph-topics{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));align-items:start;gap:32px 24px}
.ph-topics-single{grid-template-columns:minmax(0,1fr);max-width:800px}
.ph-topic-group{min-width:0;--ph-group-accent:#2167bf}
.ph-topic-group:nth-child(2n){--ph-group-accent:#6953b6}
.ph-topic-group>h2{display:flex;align-items:baseline;gap:9px;font-size:20px;line-height:1.3;letter-spacing:-.5px;margin:0 0 12px;padding-inline:4px;overflow-wrap:anywhere}
.ph-topic-group>h2::before{content:"";flex:none;width:6px;height:6px;align-self:center;border-radius:50%;background:var(--ph-group-accent)}
.ph-topic-list{list-style:none;margin:0;padding:2px 20px;border-radius:24px;background:linear-gradient(125deg,#ffffffd9,#ffffff9c 68%,#f0f1fa99);box-shadow:inset 0 1px 1px #fff,0 10px 26px -24px #44638266;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px)}
.ph-topic-list li:not([hidden])~li:not([hidden]) .ph-topic{border-top:1px solid #dfe5ee}
.ph-topic{position:relative;display:flex;align-items:center;gap:16px;min-height:80px;padding:17px 0;color:var(--ph-ink)}
.ph-topic-copy{min-width:0;flex:1}
.ph-topic h3{font-size:18px;font-weight:650;line-height:1.3;letter-spacing:-.35px;margin:0 0 4px;overflow-wrap:anywhere}
.ph-topic p{font-size:14px;line-height:1.5;color:#536277;margin:0;max-width:65ch;overflow-wrap:anywhere}
.ph-topic-arrow{width:15px;height:15px;flex:none;fill:none;stroke:#667b96;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round;transition:transform .18s,color .18s}
.ph-topic:focus-visible{outline-offset:4px;border-radius:8px}
.ph-topics+.text-link{margin-top:26px}
.ph-tool-detail{margin:25px 0;padding:32px;display:grid;grid-template-columns:72px 1fr auto;gap:24px;align-items:start;scroll-margin-top:125px}
.ph-tool-detail h2{font-size:29px;letter-spacing:-.8px;margin-bottom:12px}
.ph-tool-detail p{color:#4c5d74;line-height:1.6;margin:0 0 12px;max-width:640px}
.ph-tool-detail small{color:#52647a;font-size:13px}.ph-tool-detail .button{margin-top:4px;white-space:nowrap}
.ph-empty{padding:28px;background:#ffffffc9;border-radius:20px;line-height:1.6}
[hidden]{display:none!important}
.ph-notice{font:14px/1.6 var(--ph-system);color:#4c5d74;background:#fff;padding:16px 24px}
@media(hover:hover) and (pointer:fine){.ph-topic:hover h3{color:#0757c2}.ph-topic:hover .ph-topic-arrow{stroke:#0757c2;transform:translateX(3px)}.ph-category-links a:hover{color:#0757c2}}
@media(max-width:900px){.ph-tool-detail{grid-template-columns:60px 1fr}.ph-tool-detail .button{grid-column:2;justify-self:start}}
@media(max-width:640px){.ph-footer{width:calc(100% - 36px);align-items:flex-start}.ph-page{padding-top:42px}.ph-page>.section-intro{font-size:18px}.ph-tool-detail{padding:24px 20px;gap:16px;grid-template-columns:45px 1fr}.ph-tool-detail h2{font-size:23px}.ph-tool-detail .tool-icon{width:43px;height:48px}.ph-tool-detail .button{grid-column:1/-1}.ph-tool-detail p{font-size:15px}.learn-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:700px){.ph-topics{grid-template-columns:minmax(0,1fr);gap:26px}.ph-catalog{padding-top:20px}.ph-category-links{gap:20px;margin-bottom:26px}.ph-category-links a{font-size:13px;min-height:44px}.ph-catalog-intro{margin-bottom:22px}.ph-catalog .section-intro{font-size:16px;margin-top:12px}.ph-catalog-toolbar{flex-wrap:wrap;gap:9px;margin-bottom:24px}.ph-search{flex-basis:100%;max-width:none}.ph-result-count{margin-left:auto;font-size:12px}.ph-topic-group>h2{font-size:20px}.ph-topic-list{padding-inline:17px;border-radius:22px}.ph-topic{padding-block:15px;gap:12px}.ph-topic h3{font-size:17px}}
@media(max-width:360px){.learn-grid{grid-template-columns:1fr}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto!important}.motion{animation:none!important}.ph-topic-arrow,.button{transition:none!important}}
@media print{.domain-accent{background:none;color:#172335}.ph-header,.ph-footer,.ph-breadcrumb,.ph-search,.ph-category-links{display:none!important}.ph-page{padding:0}.glass{box-shadow:none;background:white;backdrop-filter:none}.ph-topics{display:block}.ph-topic-group{margin-bottom:24px}.ph-topic-list{padding:0;border:0}.ph-topic,.ph-tool-detail{break-inside:avoid}.ph-topic-arrow,.ph-result-count{display:none}.ph-tool-detail{border:1px solid #aaa;margin:12px 0}}

@media(forced-colors:active){.ph-category-links a[aria-current]::after{background:LinkText}.ph-topic-list{border:1px solid CanvasText}.ph-topic-arrow{stroke:LinkText}.ph-topic-group>h2::before{background:CanvasText}}