* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; background: var(--page); min-height: 100vh; }
main { margin: 0 auto; max-width: 1968px; padding: 24px; }
#message { max-width: 1440px; margin-inline: auto; }
/* Reserve the header, two-line controls, borders, and page padding before sizing the score. */
.player { --panel-width: clamp(340px, 28vw, 410px); --panel-heading-height: 78px; --header-crop: 7.5%; --player-chrome-height: 272px; width: 100%; max-width: calc((100dvh - var(--player-chrome-height)) * 2.05); margin-inline: auto; display: grid; grid-template-columns: minmax(0, 1fr) 0px; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; box-shadow: 0 18px 60px #0003; transition: grid-template-columns 260ms cubic-bezier(.22,.7,.25,1), max-width 260ms cubic-bezier(.22,.7,.25,1); }
.player.panel-open { max-width: calc((100dvh - var(--player-chrome-height)) * 2.05 + var(--panel-width)); grid-template-columns: minmax(0, 1fr) var(--panel-width); }
.performance { min-width: 0; align-self: start; container-type: inline-size; }
.piece-header { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 24px 3% 26px; border-bottom: 1px solid var(--line); }
.piece-heading { min-width: 0; }
.piece-composer { margin: 0 0 7px; color: var(--secondary); font-size: 11px; letter-spacing: .17em; text-transform: uppercase; }
.piece-header h1 { margin: 0; font-size: clamp(20px, 2.6cqw, 36px); font-weight: 600; letter-spacing: -.025em; line-height: 1.25; }
.about-toggle { display: flex; align-items: center; gap: 6px; flex-shrink: 0; padding: 12px 0 12px 8px; color: var(--accent); font-size: 13px; white-space: nowrap; }
.about-toggle:hover { color: var(--accent-hover); }
.about-toggle svg { width: 15px; height: 15px; transition: transform 260ms; }
.about-toggle[aria-expanded=true] svg { transform: rotate(180deg); }
.score-window { display: flow-root; overflow: hidden; }
.stage-wrap { position: relative; width: 100%; aspect-ratio: 16 / 9; margin-top: calc(-1 * var(--header-crop)); }
.instrument-rows { position: absolute; inset: 0; pointer-events: none; }
.instrument-row { position: absolute; pointer-events: auto; border: 1px solid transparent; border-radius: 5px; padding: 0; }
.instrument-row:hover { background: #ffffff05; border-color: #a5d6c540; }
.instrument-row[aria-pressed=true] { border-color: var(--part-color); box-shadow: inset 3px 0 var(--part-color); }
.instrument-row:focus-visible { outline: 2px solid var(--text); outline-offset: -3px; }
.instrument-row .focus-tag { position: absolute; top: 7px; right: 10px; font-size: clamp(6px,.6vw,10px); letter-spacing: .1em; color: var(--part-color); background: #0a121cea; padding: 3px 5px; border-radius: 3px; opacity: 0; }
.instrument-row[aria-pressed=true] .focus-tag { opacity: 1; }
canvas { display: block; width: 100%; height: 100%; }
.loading { position: absolute; inset: 0; display: flex; align-items: center; justify-content: center; gap: 14px; background: #080e15; color: var(--secondary); font-size: 14px; letter-spacing: .04em; }
.loading[hidden] { display: none; }
.loading span { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 15px #a5d6c599; }
.transport { position: relative; min-height: 80px; display: flex; align-items: flex-start; gap: 16px; padding: 15px 22px; border-top: 1px solid var(--line); background: var(--surface); }
.play-navigation { display: flex; flex-direction: column; gap: 4px; flex-shrink: 0; }
.all-pieces { display: flex; align-items: center; justify-content: center; gap: 5px; min-height: 24px; padding: 2px 6px; border-radius: 4px; color: var(--accent); font-size: 12px; line-height: 20px; text-decoration: none; white-space: nowrap; }
.all-pieces svg { width: 13px; height: 13px; flex-shrink: 0; }
.all-pieces:hover { color: var(--accent-hover); background: #a5d6c50b; }
.transport > .icon-button, .transport > .volume-control { margin-top: 3.5px; }
button { font: inherit; cursor: pointer; color: inherit; border: 0; background: transparent; transition: background .15s, color .15s; }
button:disabled { cursor: wait; opacity: .4; }
button:focus-visible, input:focus-visible, summary:focus-visible, a:focus-visible { outline: 2px solid var(--accent); outline-offset: 5px; }
button svg { width: 21px; height: 21px; fill: currentColor; vertical-align: middle; flex-shrink: 0; }
.play { display: flex; align-items: center; justify-content: center; gap: 9px; min-width: 107px; padding: 12px 17px; border-radius: 8px; background: var(--accent); color: var(--on-accent); font-size: 14px; font-weight: 650; }
.play:hover:not(:disabled) { background: var(--accent-hover); }
.icon-button { display: grid; place-items: center; width: 36px; height: 38px; border-radius: 7px; color: var(--secondary); flex-shrink: 0; }
.icon-button:hover { color: #fff; background: var(--line); }
.icon-button.active { color: var(--accent); background: #a5d6c514; }
.background-options { position: absolute; z-index: 3; right: 12px; bottom: calc(100% + 8px); width: min(280px, calc(100% - 24px)); padding: 14px 18px 20px; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); box-shadow: 0 12px 36px #0008; font-size: 13px; }
.background-options[hidden] { display: none; }
.background-options { overflow-y: auto; overscroll-behavior: contain; scrollbar-width: thin; scrollbar-color: var(--track) transparent; }
.background-heading { display: flex; justify-content: space-between; align-items: center; font-weight: 600; margin: -4px -7px 10px 0; }
.background-heading .icon-button { font-size: 23px; }
.background-choices { display: grid; gap: 6px; margin-bottom: 20px; }
.background-choices button { text-align: left; padding: 11px 12px; min-height: 44px; border: 1px solid var(--line); border-radius: 7px; color: var(--secondary); }
.background-choices button:hover { background: #ffffff06; }
.background-choices button[aria-pressed=true] { border-color: var(--accent); color: var(--accent); background: #a5d6c50b; }
.background-label { display: flex; justify-content: space-between; margin-bottom: 12px; color: var(--secondary); }
#background-value { color: var(--muted); font-variant-numeric: tabular-nums; }
#background-strength:disabled { opacity: .35; cursor: default; }
#background-status { margin: 12px 0 0; color: var(--secondary); line-height: 1.5; }
#background-status:empty { display: none; }
.timeline { flex: 1; min-width: 100px; padding-top: 4px; }
input[type=range] { display: block; appearance: none; -webkit-appearance: none; width: 100%; height: 5px; border-radius: 4px; margin: 7px 0; background: linear-gradient(to right, var(--accent) var(--progress, 0%), var(--track) var(--progress, 0%)); cursor: pointer; }
input[type=range]::-webkit-slider-thumb { appearance: none; -webkit-appearance: none; width: 13px; height: 13px; border-radius: 50%; background: var(--text); border: 2px solid var(--surface); box-shadow: 0 0 0 1px #a5d6c577; }
input[type=range]::-moz-range-thumb { width: 10px; height: 10px; border-radius: 50%; background: var(--text); border: 2px solid var(--surface); }
.timeline-labels { display: flex; justify-content: space-between; margin-top: 9px; font-size: 11px; color: var(--muted); font-variant-numeric: tabular-nums; }
#bar { color: var(--secondary); }
.volume-control { display: flex; align-items: center; gap: 5px; }
.volume-control input { width: 66px; --progress: 100%; }
#message { color: #e5c8a0; font-size: 13px; min-height: 0; margin-block: 8px; }
#message:empty { display: none; }
.credits { font-size: 14px; line-height: 1.7; color: var(--secondary); border-top: 1px solid var(--line); padding-top: 24px; margin-top: 28px; }
.credits summary { cursor: pointer; padding: 4px 22px 4px 0; color: var(--text); font-size: 15px; list-style: none; position: relative; }
.credits summary::-webkit-details-marker { display: none; }
.credits summary::after { content: "›"; position: absolute; right: 0; top: 0; font-size: 24px; line-height: 1.25; color: var(--accent); }
.credits[open] summary::after { transform: rotate(90deg); }
.credits p { max-width: 950px; }
a { color: var(--accent); text-underline-offset: 3px; }
.keyboard-help { color: var(--muted); }
.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; }
.player:fullscreen { border: 0; border-radius: 0; max-width: none; width: 100%; height: 100%; align-items: center; }
.player:fullscreen .performance { align-self: center; width: 100%; }
.player:fullscreen .information-panel { align-self: stretch; }
@media (min-width: 1101px) {
 /* Constrain the score's grid track, so spare space sits outside the joined score and panel. */
 .player:fullscreen { --panel-width: clamp(340px, 28vw, 520px); --panel-heading-height: clamp(78px, calc(var(--panel-width) * .19), 99px); --fullscreen-score-width: calc((100dvh - clamp(229px, 24dvh, 274px)) * 2.05); align-content: center; justify-content: center; grid-template-columns: minmax(0, min(100%, var(--fullscreen-score-width))) 0px; }
 .player.panel-open:fullscreen { grid-template-columns: minmax(0, min(100% - var(--panel-width), var(--fullscreen-score-width))) var(--panel-width); }
 /* Match the panel's first line while keeping a full-sized click target. */
 .player.panel-open .about-toggle { align-self: flex-start; min-height: 44px; padding-block: 0; margin-top: calc((var(--panel-heading-height) - 44px) / 2 - 24px); }
 .player:fullscreen .piece-composer { font-size: clamp(11px, .9cqw, 18px); }
 .player:fullscreen .piece-header h1 { font-size: clamp(20px, 2.6cqw, 52px); }
 .player:fullscreen .about-toggle { font-size: clamp(13px, 1.1cqw, 20px); }
 .player:fullscreen .about-toggle svg { width: 1.15em; height: 1.15em; }
 .player:fullscreen .information-panel { container-type: inline-size; }
 .player:fullscreen .panel-reading { padding-inline: clamp(30px, 7.3cqw, 38px); }
 .player:fullscreen .panel-top p { font-size: clamp(11px, 2.7cqw, 14px); }
 .player:fullscreen .piece-information h2 { font-size: clamp(29px, 7.1cqw, 37px); }
 .player:fullscreen .piece-information p { font-size: clamp(16px, 3.9cqw, 20px); }
 .player:fullscreen .listening-guide dt { font-size: clamp(17px, 4.15cqw, 21px); }
 .player:fullscreen .listening-guide dd { font-size: clamp(15px, 3.66cqw, 19px); }
 .player:fullscreen .music-background h2 { font-size: clamp(24px, 5.86cqw, 30px); }
 .player:fullscreen .credits summary { font-size: clamp(15px, 3.66cqw, 19px); }
 .player:fullscreen .credits p { font-size: clamp(14px, 3.42cqw, 18px); }
}
@media (max-width: 760px) {
 main { padding: 10px; }
 .player, .player.panel-open, #message { width: 100%; max-width: none; }
 .piece-header { padding: 18px 16px; align-items: flex-start; gap: 14px; }
 .piece-composer { font-size: 9px; }
 .piece-header h1 { font-size: 20px; }
 .about-toggle { font-size: 12px; padding-top: 0; }
 .transport { padding: 12px; gap: 8px; flex-wrap: wrap; }
 .play { min-width: 88px; padding: 10px 12px; }
 .transport > .icon-button, .transport > .volume-control { margin-top: 1.5px; }
 .volume-control input { width: 50px; }
}
@media (prefers-reduced-motion: reduce) { button { transition: none; } }

.information-panel { position: relative; min-width: 0; overflow: hidden; visibility: hidden; background: var(--panel); transition: visibility 260ms; }
.panel-open .information-panel { visibility: visible; box-shadow: inset 1px 0 var(--line); }
.panel-reading { position: absolute; inset: 0; width: var(--panel-width); overflow-y: auto; overscroll-behavior: contain; scrollbar-width: thin; scrollbar-color: var(--track) transparent; padding: 0 30px 32px; transform: translateX(24px); opacity: 0; transition: transform 260ms cubic-bezier(.22,.7,.25,1), opacity 180ms; }
.panel-open .panel-reading { transform: translateX(0); opacity: 1; }
.panel-scroll-cue { position: absolute; inset: auto 1px 0; z-index: 2; display: flex; align-items: center; justify-content: center; gap: 4px; height: 62px; padding-top: 24px; color: var(--accent); background: linear-gradient(transparent, var(--panel) 55%); font-size: 12px; }
.panel-scroll-cue[hidden] { display: none; }
.panel-scroll-cue span { font-size: 17px; }
.panel-scroll-cue:hover { color: var(--accent-hover); }
.panel-scroll-cue:focus-visible { outline-offset: -5px; }
.panel-top { position: sticky; top: 0; z-index: 1; display: flex; align-items: center; justify-content: space-between; gap: 16px; min-height: var(--panel-heading-height); background: var(--panel); }
.panel-top p { margin: 0; color: var(--accent); font-size: 11px; font-weight: 500; letter-spacing: .13em; text-transform: uppercase; }
.panel-close { display: grid; place-items: center; width: 44px; height: 44px; margin-right: -12px; border-radius: 50%; color: var(--text); }
.panel-close:hover { background: var(--line); }
.panel-close svg { width: 23px; height: 23px; }
.piece-information h2 { font-size: 29px; font-weight: 550; letter-spacing: -.025em; line-height: 1.2; margin: 6px 0 20px; }
.piece-information p { margin: 0 0 18px; color: var(--secondary); font-size: 16px; line-height: 1.65; }
.piece-information .listening-intro { color: var(--text); }
.listening-guide { margin: 28px 0; }
.listening-guide div + div { margin-top: 22px; }
.listening-guide dt { font-size: 17px; font-weight: 550; margin-bottom: 4px; }
.listening-guide dd { margin: 0; color: var(--secondary); font-size: 15px; line-height: 1.6; }
.music-background { border-top: 1px solid var(--line); padding-top: 27px; }
.music-background h2 { font-size: 24px; margin: 0 0 14px; }
.credits p { font-size: 14px; margin-top: 18px; overflow-wrap: anywhere; }
@media (max-width: 1100px) {
 .player, .player.panel-open { grid-template-columns: minmax(0, 1fr); }
 .information-panel { height: 0; transition: height 260ms cubic-bezier(.22,.7,.25,1), visibility 260ms; }
 .panel-open .information-panel { height: min(620px, 70dvh); box-shadow: inset 0 1px var(--line); }
 .panel-reading { width: 100%; transform: translateY(16px); }
 .panel-open .panel-reading { transform: translateY(0); }
 .piece-information { max-width: 620px; margin-inline: auto; }
 .player:fullscreen { display: block; overflow-y: auto; }
 .player:fullscreen .performance { margin-inline: auto; }
 .about-toggle svg { transform: rotate(90deg); }
 .about-toggle[aria-expanded=true] svg { transform: rotate(-90deg); }
}
@container (max-width: 600px) {
 .piece-header { flex-wrap: wrap; gap: 5px; }
 .piece-heading { flex-basis: 100%; }
 .about-toggle { padding: 8px 0 0; }
 .transport { display: grid; grid-template-columns: auto auto 1fr auto auto; padding: 12px; gap: 10px 8px; }
 .play { min-width: 88px; padding: 10px 12px; }
 .timeline { grid-row: 2; grid-column: 1 / -1; min-width: 0; padding-top: 0; }
 .volume-control { justify-self: end; }
 .volume-control input { width: 42px; }
}
@media (prefers-reduced-motion: reduce) {
 .player, .information-panel, .panel-reading, .about-toggle svg { transition: none; }
}