/* Background ownership: only .how-tree-scene paints the opening forest.
   All later chapters use reading surfaces. No page-wide forest, fog,
   continuation picture or duplicate pseudo-element paints behind them. */
body.how-background.nw-clean-page{--bg:#142e32;--bg-elevated:#19373b;--text:#f0ecdf;--text-muted:#b5c8c3;--accent:#e2ca96;--accent-soft:#d2d9bc;background:var(--bg);background-image:none;isolation:isolate}
html[data-theme=dim] body.how-background.nw-clean-page{--bg:#102529;--bg-elevated:#152e32;--text:#d5d6c9;--text-muted:#a6bab5;--accent:#c8b486;--accent-soft:#b8c3a8}
html[data-theme=dawn] body.how-background.nw-clean-page{--bg:#f6f3ee;--bg-elevated:#eeebe5;--text:#2a3840;--text-muted:#53666a;--accent:#806026;--accent-soft:#536e61}
body.how-background.nw-clean-page::before,body.how-background.nw-clean-page::after{content:none;background:none;animation:none}
.how-background .how-main{max-width:none;margin:0;padding:0;background:none;filter:none;mix-blend-mode:normal}
.how-background .how-main::before,.how-background .how-main::after{content:none}
.how-background .how-opening{max-width:1280px;margin:auto;padding:36px 40px 48px;background:none}
.how-background .how-opening::before,.how-background .how-opening::after{content:none}
.how-background .how-breadcrumb{margin-bottom:36px}
.how-background .how-opening-grid{display:grid;grid-template-columns:1fr 1fr;align-items:center;gap:40px;background:none}
.how-background .how-opening-copy{max-width:530px;background:none}
.how-background .how-opening-grid::before,.how-background .how-opening-grid::after,.how-background .how-opening-copy::before,.how-background .how-opening-copy::after{content:none}
.how-background .how-opening h1{font-size:clamp(2.8rem,4.5vw,4.3rem)}
.how-background .how-tree-scene{position:relative;isolation:isolate;margin:0;min-width:0;overflow:hidden;pointer-events:none;background:none;background-image:none;border:0;border-radius:0;box-shadow:none}
.how-background .how-tree-scene::before,.how-background .how-tree-scene::after{content:none}
.how-background .how-tree-image{position:static;display:block;width:100%;height:auto;border:0;border-radius:0;box-shadow:none;background:none;opacity:1;filter:none;mix-blend-mode:normal;object-fit:contain;mask-image:linear-gradient(to bottom,#000 0%,#000 97%,transparent 100%);-webkit-mask-image:linear-gradient(to bottom,#000 0%,#000 97%,transparent 100%)}
.how-background .how-chapter{max-width:1150px;margin:auto;padding:52px 40px;background:none;background-image:none}
.how-background .how-chapter::before,.how-background .how-chapter::after{content:none}
.how-background .steps{gap:22px}
.how-background .steps>div{padding:28px 24px;border:1px solid var(--border);border-radius:20px;background:var(--surface)}
.how-background .steps h2{font-size:1.6rem;margin-top:20px}
.how-background .how-dialogue-chapter{max-width:1150px;margin:auto;padding:52px 40px;display:grid;grid-template-columns:1fr 1.1fr;gap:48px;align-items:start;background:none;background-image:none}
.how-background .how-dialogue-chapter::before,.how-background .how-dialogue-chapter::after{content:none}
.how-background .how-chat-panel{display:block;border-radius:22px;background:var(--bg-elevated);border:1px solid var(--border);box-shadow:none}
.how-background .how-chat-panel .story-body{padding:28px}
.how-background .how-message{padding:14px 16px;border-radius:12px;background:var(--surface);border-left:2px solid var(--accent)}
.how-background .how-message-night{border-left-color:var(--accent-soft)}
.how-background .how-memory{max-width:1150px}
.how-background .how-reading{max-width:760px}
.how-background .how-privacy{margin-top:24px}
.how-background .how-privacy a{display:inline-block;padding:8px 0}
.how-background .how-safety{padding-top:36px;padding-bottom:80px}
.how-background .how-safety p{max-width:700px}
.how-background .how-help-link{display:inline-block;margin-bottom:12px}
.how-background .footer{background:none;background-image:none}
.how-background .footer::before,.how-background .footer::after{content:none}
@media(max-width:900px){.how-background .how-opening{padding-inline:24px}.how-background .how-opening-grid{gap:24px}.how-background .how-chapter,.how-background .how-dialogue-chapter{padding-inline:24px}.how-background .how-dialogue-chapter{gap:28px}}
@media(max-width:740px){.how-background .how-opening{padding:24px 16px 20px}.how-background .how-breadcrumb{margin-bottom:28px}.how-background .how-opening-grid{grid-template-columns:1fr;gap:16px}.how-background .how-opening-copy{max-width:600px}.how-background .how-opening h1{font-size:clamp(2.8rem,9vw,4rem)}.how-background .how-tree-scene{max-width:600px;margin:auto;width:100%}.how-background .how-chapter,.how-background .how-dialogue-chapter{padding:40px 16px}.how-background .steps{grid-template-columns:1fr;gap:18px}.how-background .how-dialogue-chapter{grid-template-columns:1fr;gap:18px}.how-background .how-chat-panel .story-body{padding:24px 20px}.how-background .how-safety{padding-bottom:65px}.how-background .how-safety .actions>.button{width:100%}}