:root {
    color-scheme: dark;
    --acoustic-ink: #f7fbff;
    --acoustic-muted: #b9cad8;
    --acoustic-surface: #12222d;
    --acoustic-surface-2: #19313f;
    --acoustic-line: #3b5968;
    --acoustic-blue: #6dc5ff;
    --acoustic-green: #68d9a5;
    --acoustic-focus: #ffd166;
}

body {
    margin: 0;
    min-height: 100vh;
    background: #09151d;
    color: var(--acoustic-ink);
    font-family: 'Space Grotesk', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}
#global-menu-container { background: #111d2f; }
#global-footer-container { min-height: 430px; background: #121d2f; }
[hidden] { display: none !important; }
.skip-link { position: fixed; left: 1rem; top: -4rem; z-index: 1000; background: var(--acoustic-focus); color: #172026; padding: .75rem 1rem; }
.skip-link:focus { top: 1rem; }
.acoustic-shell { width: min(1180px, calc(100% - 2rem)); margin: 0 auto; padding: 2rem 0 4rem; }
.acoustic-intro { display: flex; justify-content: space-between; align-items: end; gap: 3rem; padding: 2.5rem 0 3rem; border-bottom: 1px solid var(--acoustic-line); }
.product-kicker { color: var(--acoustic-green); font-weight: 700; margin: 0 0 .8rem; }
.acoustic-intro h1 { max-width: 15ch; font-size: clamp(2.4rem, 5vw, 4.5rem); line-height: 1; letter-spacing: -.03em; margin: 0; text-wrap: balance; }
.intro-copy { max-width: 66ch; color: var(--acoustic-muted); font-size: 1.15rem; line-height: 1.7; margin: 1.4rem 0 0; }
.intro-links { display: grid; gap: .8rem; min-width: 13rem; }
.intro-links a, .text-button { color: #8ad2ff; text-decoration: underline; text-underline-offset: .25rem; }
.text-button { background: transparent; border: 0; font-weight: 700; padding: .5rem 0; }
.pathway-choice { padding: 4rem 0; }
.section-heading { max-width: 70ch; }
.section-heading h2 { font-size: clamp(1.8rem, 4vw, 3rem); margin: 0 0 1rem; }
.section-heading p { color: var(--acoustic-muted); line-height: 1.7; }
.pathway-options { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin: 2rem 0 1.5rem; }
.pathway-button { min-height: 11rem; padding: 1.6rem; text-align: left; color: var(--acoustic-ink); background: var(--acoustic-surface); border: 1px solid var(--acoustic-line); border-radius: 14px; box-shadow: 0 14px 28px rgba(0,0,0,.22); cursor: pointer; }
.pathway-button:hover { background: var(--acoustic-surface-2); transform: translateY(-2px); }
.pathway-title { display: block; font-size: 1.35rem; font-weight: 750; margin-bottom: .75rem; }
.pathway-button span:last-child { color: var(--acoustic-muted); line-height: 1.55; }
.trainer-workspace { display: grid; grid-template-columns: minmax(15rem, 20rem) 1fr; gap: 2.5rem; padding: 3rem 0; }
.journey-rail { border-right: 1px solid var(--acoustic-line); padding-right: 2rem; }
.pathway-label { color: var(--acoustic-green); font-weight: 700; }
.journey-rail ol { list-style: none; padding: 0; margin: 1.5rem 0 2.5rem; }
.journey-rail li { color: var(--acoustic-muted); padding: .55rem 0; }
.journey-rail li[aria-current="step"] { color: var(--acoustic-ink); font-weight: 750; }
.journey-rail li[data-complete="true"] { color: var(--acoustic-green); }
.advanced-settings { border-top: 1px solid var(--acoustic-line); padding-top: 1rem; }
.advanced-settings summary { cursor: pointer; font-weight: 700; }
.advanced-settings label { display: block; margin: 1rem 0 .35rem; }
.advanced-settings select, .advanced-settings input, .recognition-controls input, textarea { width: 100%; background: #081219; color: var(--acoustic-ink); border: 1px solid var(--acoustic-line); border-radius: 8px; padding: .72rem; }
.speed-fields { display: grid; grid-template-columns: 1fr 1fr; gap: .75rem; }
.field-help { color: var(--acoustic-muted); font-size: .9rem; line-height: 1.55; }
.stage-panel { min-width: 0; }
.stage-meta { display: flex; justify-content: space-between; color: var(--acoustic-muted); }
.stage-panel h2 { font-size: clamp(2rem, 5vw, 3.6rem); margin: .5rem 0 1rem; letter-spacing: -.025em; }
#workspaceHeading:focus { outline: none; }
.stage-instruction { max-width: 70ch; min-height: 3.5rem; color: var(--acoustic-muted); font-size: 1.1rem; line-height: 1.65; }
.learner-action {
    max-width: 70ch;
    margin: 0 0 1rem;
    padding: .9rem 1rem;
    border-radius: 12px;
    background: #102938;
    color: #dff8ed;
    font-weight: 650;
    line-height: 1.5;
}
.learner-action::before { content: 'Your action: '; color: var(--acoustic-green); }
.audio-safety { padding: 1rem 0 1.5rem; }
.audio-safety p { color: var(--acoustic-muted); }
.sound-stage { min-height: 17rem; display: grid; place-items: center; align-content: center; gap: 1.25rem; background: var(--acoustic-surface); border-radius: 16px; padding: 2rem; box-shadow: 0 18px 38px rgba(0,0,0,.25); }
.concealed-identity { font-size: clamp(5rem, 15vw, 9rem); font-weight: 800; line-height: 1; }
.revealed-identity {
    width: min(100%, 46rem);
    display: grid;
    grid-template-columns: minmax(9rem, 12rem) 1fr;
    gap: clamp(1.5rem, 4vw, 3rem);
    align-items: center;
}
.identity-glyph {
    aspect-ratio: 1;
    display: grid;
    place-items: center;
    border-radius: 14px;
    background: #081219;
    color: var(--acoustic-ink);
}
.identity-glyph span { font-size: clamp(4.75rem, 10vw, 7.5rem); font-weight: 800; line-height: 1; }
.identity-copy { min-width: 0; }
.identity-kicker { margin: 0 0 .45rem; color: var(--acoustic-green); font-weight: 750; }
.identity-copy h3 { margin: 0; font-size: clamp(1.8rem, 4vw, 2.7rem); line-height: 1.1; letter-spacing: -.02em; }
.identity-copy > p:not(.identity-kicker) { margin: .75rem 0 1.25rem; color: var(--acoustic-muted); line-height: 1.55; }
.identity-actions { display: flex; flex-wrap: wrap; gap: .75rem; }
.notation-reference {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: .35rem 1rem;
    align-items: center;
    margin-top: 1rem;
    padding: .9rem 1rem;
    border-radius: 10px;
    background: #071219;
}
.notation-reference span { color: var(--acoustic-muted); font-size: .9rem; }
.notation-reference code { color: var(--acoustic-green); font-size: 1.4rem; font-weight: 750; letter-spacing: .18em; }
.notation-reference small { grid-column: 1 / -1; color: var(--acoustic-muted); line-height: 1.45; }
.known-target-summary { display: flex; gap: .75rem; align-items: baseline; color: var(--acoustic-muted); }
.known-target-summary strong { color: var(--acoustic-ink); font-size: 2rem; }
.sound-actions, .stage-navigation { display: flex; gap: .75rem; flex-wrap: wrap; justify-content: center; }
button { font: inherit; }
.primary-button, .secondary-button, .observation-options button, .paddle-button { min-height: 44px; border-radius: 10px; padding: .75rem 1rem; cursor: pointer; }
.primary-button { background: var(--acoustic-green); color: #092017; border: 1px solid var(--acoustic-green); font-weight: 800; }
.secondary-button, .observation-options button, .paddle-button { background: transparent; color: var(--acoustic-ink); border: 1px solid var(--acoustic-line); }
.action-link { display: inline-flex; align-items: center; text-decoration: none; }
button:disabled { opacity: .45; cursor: not-allowed; }
button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible, summary:focus-visible { outline: 3px solid var(--acoustic-focus); outline-offset: 3px; }
kbd { font-size: .78em; opacity: .75; }
.recognition-controls, .instructor-controls, .task-controls { margin-top: 1.5rem; padding: 1.5rem; border: 1px solid var(--acoustic-line); border-radius: 14px; background: #0d1d27; }
.recognition-controls { display: grid; grid-template-columns: 1fr auto; gap: .75rem; align-items: end; }
.recognition-controls label { grid-column: 1 / -1; }
.task-controls > p:first-child { margin-top: 0; color: var(--acoustic-muted); line-height: 1.6; }
.task-actions { display: flex; flex-wrap: wrap; gap: .75rem; align-items: center; }
.sending-pattern {
    display: block;
    width: 100%;
    min-height: 3.5rem;
    margin: 1rem 0;
    padding: .8rem 1rem;
    border-radius: 10px;
    background: #071219;
    color: var(--acoustic-green);
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: .18em;
    text-align: center;
}
.paddle-controls { display: grid; grid-template-columns: 1fr 1fr; gap: .75rem; margin-bottom: .75rem; }
.paddle-button { min-height: 64px; font-size: 1.05rem; font-weight: 750; }
.paddle-button:active { background: var(--acoustic-surface-2); }
.sending-controls a { color: #8ad2ff; }
.observation-options { display: flex; flex-wrap: wrap; gap: .6rem; margin: 1rem 0; }
.indicator-group { display: grid; grid-template-columns: repeat(5, 1fr); gap: 1rem; margin: 2rem 0; }
.indicator-group div { display: grid; gap: .5rem; }
.indicator-group span { color: var(--acoustic-muted); font-size: .9rem; }
progress { width: 100%; accent-color: var(--acoustic-green); }
.stage-message { min-height: 2rem; color: var(--acoustic-muted); text-align: center; margin: 1rem 0; }
.stage-navigation { justify-content: space-between; border-top: 1px solid var(--acoustic-line); padding-top: 1.5rem; }
@media (prefers-reduced-motion: no-preference) { .pathway-button { transition: background-color .2s ease-out, transform .2s ease-out; } }
@media (max-width: 800px) {
    .acoustic-shell { padding-top: 1rem; }
    .acoustic-intro, .trainer-workspace { display: block; }
    .intro-links { margin-top: 2rem; }
    .pathway-options, .indicator-group { grid-template-columns: 1fr; }
    .journey-rail { border-right: 0; border-bottom: 1px solid var(--acoustic-line); padding: 0 0 2rem; margin-bottom: 2rem; }
    .journey-rail ol { display: flex; overflow-x: auto; gap: 1rem; }
    .journey-rail li { min-width: 9rem; }
    .recognition-controls { grid-template-columns: 1fr; }
    .recognition-controls label { grid-column: auto; }
    .revealed-identity { grid-template-columns: 1fr; text-align: center; }
    .identity-glyph { width: 9rem; margin: 0 auto; }
    .identity-actions { justify-content: center; }
    .notation-reference { text-align: left; }
}