/* ============================================================
   PyGX tutorial page
   ============================================================ */
.grad { background: linear-gradient(100deg, var(--accent-bright), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.page-head { position: relative; overflow: hidden; padding-block: clamp(56px, 8vw, 92px) clamp(24px, 3vw, 40px); }
.page-head-bg { position: absolute; inset: 0; z-index: 0; pointer-events: none; background: radial-gradient(55% 80% at 80% -10%, var(--accent-soft), transparent 60%); }
.page-head .wrap { position: relative; z-index: 1; }
.page-head h1 { font-size: clamp(2.6rem, 5.2vw, 4rem); margin-top: 14px; }
.page-head .lede { margin-top: 20px; max-width: 66ch; }
.page-head .lede strong { color: var(--text-strong); }

/* layout */
.tut-layout { display: grid; grid-template-columns: 210px 1fr; gap: 56px; padding-block: 34px 90px; align-items: start; }
.tut-toc { position: sticky; top: calc(var(--nav-h) + 24px); display: flex; flex-direction: column; gap: 2px; }
.tut-toc-h { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: .14em; text-transform: uppercase; color: var(--faint); margin-bottom: 10px; }
.tt-link { display: flex; gap: 10px; align-items: baseline; padding: 8px 12px; border-radius: var(--r-sm); font-size: 0.9rem; color: var(--muted); border-left: 2px solid var(--border); border-radius: 0 var(--r-sm) var(--r-sm) 0; transition: all .15s; }
.tt-link span { font-family: var(--font-mono); font-size: 0.72rem; color: var(--faint); }
.tt-link:hover { color: var(--text-strong); background: var(--surface-2); }
.tt-link.on { color: var(--accent); border-left-color: var(--accent); background: var(--accent-soft); }
.tt-link.on span { color: var(--accent); }

.tut-main { min-width: 0; display: flex; flex-direction: column; gap: 74px; }
.tut-ch { scroll-margin-top: calc(var(--nav-h) + 20px); }
.tut-ch-h { display: flex; align-items: baseline; gap: 14px; margin-bottom: 14px; }
.tut-n { font-family: var(--font-mono); font-size: 0.9rem; color: var(--accent); font-weight: 700; }
.tut-ch h2 { font-size: clamp(1.6rem, 2.6vw, 2.1rem); }
.tut-ch > p { color: var(--muted); max-width: 68ch; font-size: 1.0rem; }
.tut-ch > p strong { color: var(--text-strong); }
.tut-note { margin-top: 14px; font-size: 0.9rem; color: var(--faint); }

.demo { margin-top: 22px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--r-xl); padding: 26px; box-shadow: var(--shadow-sm); }
.demo-h { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: .12em; text-transform: uppercase; color: var(--faint); margin-bottom: 16px; }
.demo .btn { font-size: 0.86rem; padding: .55em 1em; }
.demo-code { font-family: var(--font-mono); font-size: 0.86rem; background: var(--code-bg); color: var(--code-fg); border-radius: var(--r-md); padding: 13px 16px; overflow-x: auto; }

/* 01 duality */
.dual { display: grid; grid-template-columns: 1fr auto 1fr; gap: 18px; align-items: stretch; }
.dual-panel { border: 1px solid var(--border); border-radius: var(--r-md); padding: 18px; background: var(--surface-2); transition: border-color .3s, box-shadow .3s; }
.dual-panel.flash { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.dual-panel h5 { font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); margin: 0 0 12px; font-weight: 500; }
.dual-kv { font-family: var(--font-mono); font-size: 0.92rem; display: flex; flex-direction: column; gap: 7px; color: var(--muted); }
.dual-kv b { color: var(--text-strong); font-weight: 500; }
.dual-kv .v { color: var(--accent); font-weight: 700; display: inline-block; transition: transform .25s; }
.dual-kv .v.pop { transform: scale(1.35); }
.dual-mid { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 6px; color: var(--faint); }
.dual-arrow { width: 54px; height: 22px; }
.dual-arrow path { stroke: var(--border-strong); stroke-width: 2; fill: none; transition: stroke .3s; }
.dual-arrow.go path { stroke: var(--accent); }
.dual-mid .lab { font-family: var(--font-mono); font-size: 0.66rem; }
.dual-ctl { display: flex; gap: 10px; align-items: center; margin-top: 18px; flex-wrap: wrap; }
.dual-log { font-family: var(--font-mono); font-size: 0.8rem; color: var(--muted); }
.dual-log b { color: var(--accent); }

/* 02 tree + 03 events */
.ttree { display: flex; flex-direction: column; align-items: center; gap: 0; padding: 8px 0 4px; }
.ttree-row { display: flex; gap: 26px; justify-content: center; }
.tnode { position: relative; display: flex; flex-direction: column; align-items: center; cursor: pointer; padding: 0 6px; }
.tnode-box { display: flex; align-items: center; gap: 7px; border: 1.5px solid var(--border-strong); background: var(--surface); border-radius: 10px; padding: 7px 13px; font-family: var(--font-mono); font-size: 0.88rem; color: var(--text-strong); transition: all .18s; }
.tnode-box .nv { color: var(--accent); font-weight: 700; display: inline-block; transition: transform .25s; }
.tnode-box .nv.pop { transform: scale(1.4); }
.tnode:hover > .tnode-box { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.tnode-box.pulse { border-color: var(--accent); background: var(--accent-soft); box-shadow: 0 0 0 4px var(--accent-soft); }
.tnode-box.pulse::after { content: attr(data-badge); position: absolute; top: -11px; right: -10px; background: var(--accent); color: #fff; font-size: 0.62rem; font-family: var(--font-mono); padding: 2px 7px; border-radius: 999px; white-space: nowrap; z-index: 2; }
[data-theme="dark"] .tnode-box.pulse::after { color: oklch(0.16 0.012 285); }
.tnode-box { position: relative; z-index: 1; }
.tlines { width: 100%; height: 26px; }
.tlines line { stroke: var(--border-strong); stroke-width: 1.5; }
.tpath-bar { margin-top: 14px; display: flex; align-items: center; gap: 10px; font-family: var(--font-mono); font-size: 0.82rem; color: var(--muted); border-top: 1px solid var(--border); padding-top: 14px; flex-wrap: wrap; }
.tpath-bar b { color: var(--accent); font-weight: 500; }
.tpath-bar .demo-code { flex: 1; min-width: 240px; padding: 8px 12px; font-size: 0.78rem; }

/* 04 validation */
.val { display: flex; flex-direction: column; gap: 16px; }
.val-spec { font-family: var(--font-mono); font-size: 0.88rem; color: var(--muted); }
.val-spec b { color: var(--accent); }
.val-btns { display: flex; gap: 10px; flex-wrap: wrap; }
.val-btn { font-family: var(--font-mono); font-size: 0.9rem; padding: 8px 16px; border-radius: 9px; border: 1px solid var(--border-strong); background: var(--surface-2); color: var(--text-strong); transition: all .15s; }
.val-btn:hover { border-color: var(--accent); color: var(--accent); }
.val-field { display: flex; align-items: center; gap: 12px; border: 1.5px solid var(--border-strong); border-radius: var(--r-md); padding: 13px 17px; font-family: var(--font-mono); font-size: 0.94rem; background: var(--surface-2); transition: all .2s; }
.val-field .slot { color: var(--accent); font-weight: 700; min-width: 3ch; }
.val-field.ok { border-color: oklch(0.62 0.15 155); box-shadow: 0 0 0 3px oklch(0.62 0.15 155 / 0.16); }
.val-field.bad { border-color: oklch(0.6 0.19 25); box-shadow: 0 0 0 3px oklch(0.6 0.19 25 / 0.14); animation: shake .3s; }
@keyframes shake { 25% { transform: translateX(-5px);} 75% { transform: translateX(5px);} }
.val-msg { font-family: var(--font-mono); font-size: 0.82rem; min-height: 1.4em; }
.val-msg.ok { color: oklch(0.55 0.14 155); }
.val-msg.bad { color: oklch(0.58 0.19 25); }

/* 05 placeholding */
.ph { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.ph-side h5 { font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); margin: 0 0 12px; font-weight: 500; }
.ph-obj { font-family: var(--font-mono); font-size: 0.9rem; border: 1px solid var(--border); border-radius: var(--r-md); padding: 16px 18px; background: var(--surface-2); line-height: 2; color: var(--text-strong); }
.hole { display: inline-flex; align-items: center; justify-content: center; min-width: 74px; padding: 1px 10px; border: 1.5px dashed var(--accent-line); border-radius: 7px; color: var(--faint); font-size: 0.8rem; background: var(--accent-soft); transition: all .3s; }
.hole.filled { border-style: solid; border-color: var(--accent); color: var(--accent); font-weight: 700; font-size: 0.9rem; background: transparent; }
.ph-status { display: flex; gap: 8px; margin-top: 12px; flex-wrap: wrap; }
.ph-badge { font-family: var(--font-mono); font-size: 0.72rem; padding: 4px 10px; border-radius: 999px; border: 1px solid var(--border); color: var(--muted); background: var(--surface-2); transition: all .25s; }
.ph-badge.on { border-color: var(--accent-line); background: var(--accent-soft); color: var(--accent); }
.ph-badge.fire { border-color: oklch(0.62 0.15 155); background: oklch(0.62 0.15 155 / 0.14); color: oklch(0.5 0.14 155); }
.ph-ctl { margin-top: 14px; display: flex; gap: 10px; flex-wrap: wrap; }
@media (max-width: 760px) { .ph { grid-template-columns: 1fr; } }

/* 06 detour */
.det { display: flex; flex-direction: column; gap: 18px; }
.det-toggle { display: inline-flex; align-items: center; gap: 12px; cursor: pointer; user-select: none; font-family: var(--font-mono); font-size: 0.88rem; color: var(--text-strong); }
.det-sw { width: 44px; height: 24px; border-radius: 999px; background: var(--border-strong); position: relative; transition: background .2s; flex-shrink: 0; }
.det-sw::after { content: ""; position: absolute; top: 3px; left: 3px; width: 18px; height: 18px; border-radius: 50%; background: #fff; transition: left .2s; box-shadow: var(--shadow-sm); }
.det-toggle.on .det-sw { background: var(--accent); }
.det-toggle.on .det-sw::after { left: 23px; }
.det-stage { position: relative; display: grid; grid-template-columns: auto 1fr auto; gap: 14px 40px; align-items: center; padding: 10px 6px; }
.det-call, .det-cls { font-family: var(--font-mono); font-size: 0.9rem; border: 1.5px solid var(--border-strong); border-radius: 10px; padding: 10px 16px; background: var(--surface-2); color: var(--text-strong); text-align: center; transition: all .25s; }
.det-cls.dim { opacity: 0.38; }
.det-cls.hot { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.det-arrows { height: 92px; width: 100%; }
.det-arrows path { fill: none; stroke-width: 2; transition: stroke .25s, opacity .25s; }
.det-cols { display: flex; flex-direction: column; gap: 14px; }
.det-result { font-family: var(--font-mono); font-size: 0.88rem; color: var(--muted); border-top: 1px solid var(--border); padding-top: 14px; }
.det-result b { color: var(--accent); font-size: 1.05em; }

/* next */
.tut-next { display: flex; align-items: center; justify-content: space-between; gap: 24px; flex-wrap: wrap; background: var(--bg-2); border: 1px solid var(--border); border-radius: var(--r-xl); padding: 30px 34px; }
.tut-next h3 { font-size: 1.3rem; }
.tut-next p { color: var(--muted); margin-top: 6px; max-width: 46ch; }
.tut-next-links { display: flex; gap: 12px; flex-wrap: wrap; }

/* hooks */
.hook-table { margin-top: 20px; display: flex; flex-direction: column; }
.hook { display: grid; grid-template-columns: 250px 1fr; gap: 18px; padding: 13px 4px; border-top: 1px solid var(--border); font-size: 0.92rem; }
.hook:last-child { border-bottom: 1px solid var(--border); }
.hook code { font-family: var(--font-mono); font-size: 0.84rem; color: var(--accent); }
.hook span { color: var(--muted); }
.hook span code { color: var(--text-strong); }
@media (max-width: 700px) { .hook { grid-template-columns: 1fr; gap: 4px; } }

.mobile-menu { display: none; flex-direction: column; padding: 8px 28px 16px; gap: 2px; border-bottom: 1px solid var(--border); background: var(--bg); }
.mobile-menu.open { display: flex; }
.mobile-menu a { padding: 11px 6px; color: var(--text); border-bottom: 1px solid var(--border); font-size: 0.96rem; }
.mobile-menu a:last-child { border-bottom: 0; }

@media (max-width: 880px) {
  .tut-layout { grid-template-columns: 1fr; gap: 30px; }
  .tut-toc { position: static; flex-direction: row; flex-wrap: wrap; gap: 6px; }
  .tut-toc-h { display: none; }
  .tt-link { border: 1px solid var(--border); border-radius: 999px; padding: 6px 13px; }
  .tt-link.on { border-color: var(--accent-line); }
  .dual { grid-template-columns: 1fr; }
  .dual-mid { transform: rotate(90deg); height: 40px; }
}