/* Animation Lab: walk cycle */
/* Layout: an animator's light table. The drawing sheet, with its peg holes, sits on a cool desk;
   the transport, exposure sheet and review panels are laid out underneath like tools on the desk. */
:root {
    --desk: #E1E5E9;
    --desk-deep: #D0D6DD;
    --paper: #FBFCFA;
    --ink: #1E2227;
    --ink-soft: #57606A;
    --rule: #C3CAD2;
    --blue: #4A86C4;
    --accent: #5B2BD6;
    --accent-ink: #FFFFFF;
    --red: #CF4336;
    --green: #2C955A;
    --shadow: rgba(24, 32, 44, 0.22);

    --font-display: 'Barlow Condensed', 'Arial Narrow', 'Roboto Condensed', sans-serif;
    --font-body: 'IBM Plex Sans', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'IBM Plex Mono', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    --font-hand: 'Caveat', 'Segoe Print', 'Bradley Hand', cursive;

    --radius: 6px;
    color-scheme: light;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --desk: #121519;
        --desk-deep: #0A0C0F;
        --paper: #1C2026;
        --ink: #E5E8EC;
        --ink-soft: #9AA3AD;
        --rule: #353C45;
        --blue: #6FA6DD;
        --accent: #A88EFF;
        --accent-ink: #15111F;
        --red: #EF7266;
        --green: #5AC688;
        --shadow: rgba(0, 0, 0, 0.55);
        color-scheme: dark;
    }
}

:root[data-theme="dark"] {
    --desk: #121519;
    --desk-deep: #0A0C0F;
    --paper: #1C2026;
    --ink: #E5E8EC;
    --ink-soft: #9AA3AD;
    --rule: #353C45;
    --blue: #6FA6DD;
    --accent: #A88EFF;
    --accent-ink: #15111F;
    --red: #EF7266;
    --green: #5AC688;
    --shadow: rgba(0, 0, 0, 0.55);
    color-scheme: dark;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    background: var(--desk);
    color: var(--ink);
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.55;
}

a {
    color: var(--accent);
    text-underline-offset: 0.18em;
}

button {
    font: inherit;
    color: inherit;
}

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.page {
    max-width: 1120px;
    margin: 0 auto;
    padding-block: 12px 40px;
    padding-left: max(16px, env(safe-area-inset-left, 0px));
    padding-right: max(16px, env(safe-area-inset-right, 0px));
    display: flex;
    flex-direction: column;
    gap: 28px;
}

/* ---------------------------------------------------------------- header */
.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    font-size: 0.875rem;
}

.back {
    font-weight: 500;
    text-decoration: none;
}

.back:hover {
    text-decoration: underline;
}

.topbar-label,
.label,
.eyebrow {
    font-size: 0.75rem;
    font-weight: 500;
    letter-spacing: 0.09em;
    text-transform: uppercase;
    color: var(--ink-soft);
}

.hero {
    display: flex;
    flex-direction: column;
    gap: 6px;
    max-width: 68ch;
}

.eyebrow {
    margin: 0;
    font-family: var(--font-mono);
    letter-spacing: 0.04em;
}

h1,
h2 {
    font-family: var(--font-display);
    text-transform: uppercase;
    text-wrap: balance;
    margin: 0;
    line-height: 1;
}

h1 {
    font-size: clamp(2.75rem, 9vw, 5rem);
    font-weight: 700;
    letter-spacing: 0.005em;
}

h2 {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: 0.03em;
}

.lead {
    margin: 6px 0 0;
    font-size: 1.0625rem;
    color: var(--ink-soft);
}

/* ----------------------------------------------------------------- stage */
.desk {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.sheet {
    background: var(--paper);
    border-radius: var(--radius);
    box-shadow: 0 1px 0 var(--rule), 0 14px 34px -22px var(--shadow);
    overflow: hidden;
}

#stage {
    display: block;
    width: 100%;
    touch-action: pan-y;
}

/* ------------------------------------------------------------- transport */
.transport {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 12px 18px;
}

.transport-buttons {
    display: flex;
    gap: 6px;
}

.tool {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    min-height: 44px;
    padding: 0 14px;
    border: 1px solid var(--rule);
    border-radius: var(--radius);
    background: var(--paper);
    cursor: pointer;
}

.tool:hover {
    border-color: var(--ink-soft);
}

.tool svg {
    width: 20px;
    height: 20px;
    fill: currentColor;
}

.tool.icon {
    width: 44px;
    padding: 0;
}

.tool.play {
    min-width: 108px;
    background: var(--accent);
    border-color: var(--accent);
    color: var(--accent-ink);
    font-weight: 600;
}

.tool.play .icon-play,
.tool.play.paused .icon-pause {
    display: none;
}

.tool.play.paused .icon-play {
    display: block;
}

.readout {
    display: flex;
    flex-direction: column;
    min-width: 0;
    flex: 1 1 200px;
    line-height: 1.3;
}

.readout-frame {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    color: var(--ink-soft);
    font-variant-numeric: tabular-nums;
}

.readout-frame strong {
    font-size: 1.375rem;
    font-weight: 500;
    color: var(--ink);
}

.readout-pose {
    font-weight: 500;
}

.transport-options {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.seg {
    display: inline-flex;
    border: 1px solid var(--rule);
    border-radius: var(--radius);
    background: var(--paper);
    overflow: hidden;
}

.seg button {
    min-height: 40px;
    padding: 0 12px;
    border: 0;
    background: transparent;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    white-space: nowrap;
}

.seg button + button {
    border-left: 1px solid var(--rule);
}

.seg button[aria-pressed="true"] {
    background: var(--ink);
    color: var(--paper);
}

/* ---------------------------------------------------------------- layers */
.layers {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
}

.layers .label {
    margin-right: 4px;
}

.chip {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    min-height: 36px;
    padding: 0 12px;
    border: 1px solid var(--rule);
    border-radius: 999px;
    background: transparent;
    font-size: 0.875rem;
    cursor: pointer;
}

.chip[aria-pressed="true"] {
    background: var(--paper);
    border-color: var(--ink);
    font-weight: 500;
}

.swatch {
    display: inline-block;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    flex: none;
}

.swatch.onion {
    background: linear-gradient(90deg, var(--red) 50%, var(--green) 50%);
}

.swatch.arcs {
    border: 2px dotted var(--accent);
}

.swatch.joints {
    border: 2px solid var(--ink);
    background: var(--paper);
}

.swatch.near {
    background: var(--ink);
}

.swatch.far {
    background: var(--blue);
}

/* ---------------------------------------------------------- exposure sheet */
.xsheet {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.xsheet-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
}

.xsheet-key {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8125rem;
    color: var(--ink-soft);
}

.xsheet-rows {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.xrow {
    display: grid;
    grid-template-columns: 5.5rem repeat(12, minmax(0, 1fr));
    align-items: stretch;
    gap: 3px;
}

.xrow-label {
    align-self: center;
    font-size: 0.75rem;
    font-weight: 500;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--ink-soft);
}

.xcell {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1px;
    min-height: 48px;
    padding: 4px 0;
    border: 1px solid var(--rule);
    border-radius: 4px;
    background: var(--paper);
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    font-variant-numeric: tabular-nums;
    cursor: pointer;
}

.xcell:hover {
    border-color: var(--ink-soft);
}

.xcell .tag {
    font-family: var(--font-hand);
    font-size: 0.9375rem;
    line-height: 1;
    color: var(--ink-soft);
}

.key-mark {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.6em;
    height: 1.6em;
    border: 1.5px solid var(--red);
    border-radius: 50%;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    line-height: 1;
    color: var(--ink);
}

.xcell.current {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--accent-ink);
}

.xcell.current .tag,
.xcell.current .key-mark {
    color: var(--accent-ink);
    border-color: var(--accent-ink);
}

@media (max-width: 560px) {
    .xrow {
        grid-template-columns: repeat(12, minmax(0, 1fr));
        gap: 2px;
    }

    .xrow-label {
        grid-column: 1 / -1;
    }

    .xcell {
        min-height: 44px;
        font-size: 0.6875rem;
    }

    .xcell .tag {
        font-size: 0.8125rem;
    }

    .key-mark {
        font-size: 0.625rem;
    }
}

/* ---------------------------------------------------------------- passes */
.section-head {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.section-head p {
    margin: 0;
    color: var(--ink-soft);
    font-size: 0.9375rem;
    max-width: 62ch;
}

.passes {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.pass-picker {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 6px;
}

.pass-picker button {
    display: flex;
    align-items: baseline;
    gap: 8px;
    min-height: 52px;
    padding: 8px 12px;
    border: 1px solid var(--rule);
    border-radius: var(--radius);
    background: var(--paper);
    text-align: left;
    cursor: pointer;
}

.pass-picker button:hover {
    border-color: var(--ink-soft);
}

.pass-picker button[aria-pressed="true"] {
    border-color: var(--accent);
    box-shadow: inset 0 0 0 1px var(--accent);
}

.pass-num {
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    color: var(--ink-soft);
}

.pass-picker button[aria-pressed="true"] .pass-num {
    color: var(--accent);
}

.pass-name {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    letter-spacing: 0.03em;
    text-transform: uppercase;
}

.pass-note {
    margin: 0;
    max-width: 68ch;
    min-height: 3.1em;
}

@media (max-width: 560px) {
    .pass-picker {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

/* ---------------------------------------------------------------- panels */
.panels {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
}

@media (min-width: 900px) {
    .panels {
        grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
        gap: 28px 36px;
    }

    .panel-wide {
        grid-column: 1 / -1;
    }
}

.panel {
    display: flex;
    flex-direction: column;
    gap: 12px;
    min-width: 0;
}

.key-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 8px;
}

@media (max-width: 560px) {
    .key-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

.key-card {
    display: flex;
    flex-direction: column;
    gap: 6px;
    padding: 0 0 10px;
    border: 1px solid var(--rule);
    border-radius: var(--radius);
    background: var(--paper);
    text-align: left;
    cursor: pointer;
    overflow: hidden;
}

.key-card:hover {
    border-color: var(--ink-soft);
}

.key-card[aria-current="true"] {
    border-color: var(--accent);
    box-shadow: inset 0 0 0 1px var(--accent);
}

.key-card canvas {
    display: block;
    width: 100%;
}

.key-card .key-title {
    padding: 0 10px;
    font-family: var(--font-display);
    font-size: 1.125rem;
    font-weight: 600;
    letter-spacing: 0.03em;
    text-transform: uppercase;
    line-height: 1.1;
}

.key-card .key-text {
    padding: 0 10px;
    font-size: 0.8125rem;
    line-height: 1.4;
    color: var(--ink-soft);
}

/* ---------------------------------------------------------------- checks */
.checks {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    border-top: 1px solid var(--rule);
}

.checks li {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr) auto;
    align-items: baseline;
    gap: 4px 12px;
    padding: 10px 0;
    border-bottom: 1px solid var(--rule);
}

.check-state {
    min-width: 4.25rem;
    padding: 2px 8px;
    border-radius: 999px;
    font-size: 0.6875rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    text-align: center;
}

.check-state.pass {
    background: var(--green);
    color: var(--paper);
}

.check-state.watch {
    background: var(--red);
    color: var(--paper);
}

.check-state.info {
    border: 1px solid var(--rule);
    color: var(--ink-soft);
}

.check-name {
    font-weight: 500;
}

.check-detail {
    grid-column: 2 / -1;
    font-size: 0.8125rem;
    color: var(--ink-soft);
}

.check-value {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    font-variant-numeric: tabular-nums;
    white-space: nowrap;
}

/* ----------------------------------------------------------------- graph */
.legend {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 18px;
    font-size: 0.8125rem;
    color: var(--ink-soft);
}

.legend > span {
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.legend .swatch {
    width: 18px;
    height: 3px;
    border-radius: 2px;
}

#graph {
    display: block;
    width: 100%;
    background: var(--paper);
    border-radius: var(--radius);
    border: 1px solid var(--rule);
}

/* ----------------------------------------------------------------- notes */
.notes {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    gap: 28px;
    padding-top: 24px;
    border-top: 1px solid var(--rule);
}

@media (min-width: 900px) {
    .notes {
        grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
        gap: 36px;
    }
}

.notes-col {
    display: flex;
    flex-direction: column;
    gap: 12px;
    min-width: 0;
}

.notes ul,
.notes ol {
    margin: 0;
    padding-left: 1.2em;
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-width: 62ch;
}

.notes li::marker {
    color: var(--ink-soft);
    font-family: var(--font-mono);
    font-size: 0.875em;
}

.next-lesson {
    display: flex;
    flex-direction: column;
    gap: 10px;
    padding-top: 24px;
    border-top: 1px solid var(--rule);
}

.next-lesson p {
    margin: 0;
    max-width: 65ch;
}

.next-link {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    padding: 0 16px;
    border-radius: var(--radius);
    background: var(--accent);
    color: var(--accent-ink);
    font-weight: 600;
    text-decoration: none;
}

.next-link:hover { filter: brightness(1.08); }

.foot {
    font-size: 0.8125rem;
    color: var(--ink-soft);
}

.foot p {
    margin: 0;
    max-width: 75ch;
}

@media (prefers-reduced-motion: reduce) {
    * {
        transition: none !important;
    }
}