/* F8 Sounds — base type, buttons, level pills and lesson content
   (panels, examples, tables, cards, diagrams, glossary lists), keyframes. */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-padding-top: calc(var(--top-h) + 12px); -webkit-text-size-adjust: 100%; }
body { margin: 0; font: 400 18px/1.65 var(--font); color: var(--text); background: var(--bg); -webkit-font-smoothing: antialiased; }
img, svg, canvas { max-width: 100%; }
a { color: var(--accent-text); text-underline-offset: 3px; }
:focus-visible { outline: 2px solid var(--accent-text); outline-offset: 2px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.skip { position: absolute; left: -999px; top: 8px; z-index: 100; padding: 10px 16px; border-radius: 99px; background: var(--accent); color: var(--on-accent); font-weight: 700; }
.skip:focus { left: 8px; }

h1 { font: 800 clamp(34px, 4.2vw, 52px)/1 var(--display); letter-spacing: -.02em; margin: 8px 0 12px; }
h2 { font: 800 clamp(23px, 2.4vw, 28px)/1.2 var(--display); letter-spacing: -.015em; margin: 44px 0 12px; }
h3 { font: 700 20px/1.25 var(--font); margin: 32px 0 8px; }
h1, h2, h3 { text-wrap: balance; }
p, li { max-width: var(--measure); }
p { text-wrap: pretty; }
/* Lesson reading: a 1.7 line height for prose (UI text keeps its own) and a little air between list items. */
main :is(p, li, dd, blockquote) { line-height: 1.7; }
main p { margin-block: .95em; }
main > :is(ul, ol) > li + li { margin-top: .25em; }
.lead { font-size: 20px; line-height: 1.5; color: var(--muted); }
.accent { color: var(--accent-text); }
hr { border: 0; border-top: 1px solid var(--line); margin: 32px 0; }
code, kbd { font-family: var(--mono); font-weight: 500; font-size: .86em; background: var(--panel); padding: 1px 6px; border-radius: 6px; }
kbd { box-shadow: 0 0 0 1px var(--line), inset 0 -1px 0 var(--line); }
mark { background: color-mix(in srgb, var(--accent) 22%, transparent); color: inherit; padding: 0 3px; border-radius: 3px; }
.mono { font-family: var(--mono); font-weight: 500; }
.ic { display: inline-block; flex: none; vertical-align: -.2em; }
.cover { display: block; flex: none; }

/* Buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 44px; padding: 0 22px; border: 0; border-radius: 99px; background: var(--accent); color: var(--on-accent) !important; font: 700 15px var(--font); text-decoration: none; cursor: pointer; transition: transform var(--dur-base) var(--ease-spring); }
.btn:active { transform: scale(.95); }
.btn-ghost { background: transparent; color: var(--text) !important; box-shadow: inset 0 0 0 1px var(--line); }
.btn-ghost:hover { background: var(--panel); }
.btn-small { min-height: 34px; padding: 0 14px; font-size: 13px; }

/* Level pills: a neutral pill with a band-coloured dot */
.lvl { display: inline-flex; align-items: center; gap: 6px; padding: 2px 9px; border-radius: 99px; box-shadow: inset 0 0 0 1px var(--line); color: var(--text); font: 700 11px var(--font); letter-spacing: .04em; text-transform: uppercase; vertical-align: middle; white-space: nowrap; }
.lvl::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--band, var(--muted)); }
.lvl-beginner { --band: #FF8A3D; } .lvl-intermediate { --band: #3DDC97; } .lvl-advanced { --band: #5B8CFF; } .lvl-expert { --band: #B565FF; } .lvl-reference { --band: #8E8E96; }

/* Callout panels */
.panel { margin: 20px 0; padding: 14px 18px; border-left: 3px solid var(--k); border-radius: var(--radius); background: var(--kb); color: var(--text); }
.panel > :first-child { margin-top: 0; } .panel > :last-child { margin-bottom: 0; }
.note { --k: var(--note); --kb: var(--note-bg); } .info { --k: var(--info); --kb: var(--info-bg); }
.warning { --k: var(--bad); --kb: var(--bad-bg); } .tip { --k: var(--ok); --kb: var(--ok-bg); }
.panel-title { display: block; margin-bottom: 4px; color: var(--k); font: 700 12px var(--font); letter-spacing: .06em; text-transform: uppercase; }

/* Examples */
.example { margin: 24px 0; padding: 14px 20px 18px; border-radius: var(--radius-lg); background: var(--panel); box-shadow: inset 0 0 0 1px var(--line); }
.example::before { content: "Example"; display: block; color: var(--muted); font: 500 11px var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.example > h3:first-of-type { margin-top: 2px; font-size: 18px; }
.example-box { margin: 10px 0 14px; padding: 12px 16px; border-left: 3px solid var(--accent); border-radius: 8px; background: var(--bg); font: 500 14px/1.6 var(--mono); white-space: pre; overflow-x: auto; }
.big-box { margin: 28px 0; padding: 24px 28px; border-radius: var(--radius-lg); background: color-mix(in srgb, var(--accent) 10%, var(--panel)); }
.big-box h2 { margin-top: 0; }

/* Tables */
.table-wrap { margin: 16px 0 24px; overflow-x: auto; }
table { width: 100%; margin: 16px 0 24px; border-collapse: collapse; font-size: 15px; font-variant-numeric: tabular-nums; }
.table-wrap table { margin: 0; }
th { padding: 10px 12px; border-bottom: 1px solid var(--line); color: var(--muted); font: 700 11px var(--font); letter-spacing: .06em; text-align: left; text-transform: uppercase; white-space: nowrap; }
td { padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }

/* Cards */
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 14px; margin: 20px 0; }
.card { display: flex; flex-direction: column; gap: 6px; padding: 14px; border-radius: var(--radius); background: var(--panel); color: var(--text) !important; text-decoration: none; transition: transform var(--dur-base) var(--ease-spring); }
a.card:hover { background: var(--raise); box-shadow: var(--raise-ring); }
a.card:active { transform: scale(.97); }
.card .cover { width: 100%; height: auto; margin-bottom: 4px; box-shadow: var(--shadow); }
.card h3 { margin: 2px 0 0; font-size: 17px; }
.card p { margin: 0; color: var(--muted); font-size: 14px; }

/* Diagrams and signal chains */
.diagram { margin: 20px 0; padding: 16px; border-radius: var(--radius); background: var(--panel); overflow-x: auto; }
.diagram figcaption { margin-top: 8px; color: var(--muted); font-size: 14px; }
.signal-chain { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; font: 500 13px var(--mono); }
.signal-chain span { padding: 6px 12px; border-radius: 8px; background: var(--bg); box-shadow: inset 0 0 0 1.5px var(--accent); }
.signal-chain i { color: var(--accent-text); font-style: normal; font-weight: 700; }

/* Glossary */
dl { margin: 12px 0 24px; }
dt { margin-top: 14px; font-weight: 700; }
dd { max-width: var(--measure); margin: 2px 0 0; padding-left: 14px; border-left: 2px solid var(--line); }

/* Motion (Tactile). Only transform and opacity animate. */
@keyframes f8-rise { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }
@keyframes f8-grow { from { transform: scaleY(0); } to { transform: scaleY(1); } }
@keyframes f8-jump { 0% { opacity: var(--unlit); transform: scaleY(.2); } 60% { opacity: 1; transform: scaleY(1.12); } 100% { opacity: 1; transform: scaleY(1); } }
@keyframes f8-ring { from { opacity: .8; transform: scale(.4); } to { opacity: 0; transform: scale(3); } }
@keyframes f8-bounce { 0%, 100% { transform: scaleY(.3); } 50% { transform: scaleY(1); } }
@keyframes f8-pulse { 0%, 100% { opacity: 1; } 50% { opacity: .45; } }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; animation-delay: 0s !important; transition-duration: .01ms !important; scroll-behavior: auto !important; }
}