:root {
    --pane-padding: 24px;
    --radius: 4px;
    --radius-sm: 3px;
    --font-sans:
        "SF Pro Text", "SF Pro Display", -apple-system, BlinkMacSystemFont,
        "Segoe UI", "Helvetica Neue", Arial, sans-serif;
    --background: #000000;
    --card: #000000;
    --card-soft: #000000;
    --surface: #000000;
    --border: #ffffff;
    --border-strong: #ffffff;
    --text: #ffffff;
    --muted: #ffffff;
    --accent: #ffffff;
    --accent-soft: #000000;
    --accent-border: #ffffff;
    --accent-border-strong: #ffffff;
    --surface-lift: #000000;
    --surface-image: #000000;
    --kbd-bg: #111111;
    --kbd-border: #2a2a2a;
    --kbd-text: #f0f0f0;
    --kbd-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.08);
    --button-bg: #000000;
    --button-bg-hover: #000000;
    --button-text: #ffffff;
    --button-border: #ffffff;
}

body[data-theme="light"] {
    --background: #ffffff;
    --card: #ffffff;
    --card-soft: #ffffff;
    --surface: #ffffff;
    --border: #000000;
    --border-strong: #000000;
    --text: #000000;
    --muted: #000000;
    --accent: #000000;
    --accent-soft: #ffffff;
    --accent-border: #000000;
    --accent-border-strong: #000000;
    --surface-lift: #ffffff;
    --surface-image: #ffffff;
    --kbd-bg: #e7e7e7;
    --kbd-border: #e0e0e0;
    --kbd-text: #5d5d5d;
    --kbd-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.9);
    --button-bg: #ffffff;
    --button-bg-hover: #ffffff;
    --button-text: #000000;
    --button-border: #000000;
}

* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    min-height: 100%;
}

body {
    position: relative;
    font-family: var(--font-sans);
    color: var(--text);
    background: var(--background);
}

button,
input,
[contenteditable="true"] {
    font: inherit;
}

button {
    cursor: pointer;
}

.app-shell {
    width: 100%;
    margin: 0;
    min-height: 100vh;
    padding: 12px;
    background: transparent;
}

.toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 14px;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 0;
    background: var(--card-soft);
    max-width: 1024px;
    margin: auto;
}

.toolbar__title {
    font-size: 0.86rem;
    font-weight: 700;
    letter-spacing: 0.11em;
    text-transform: uppercase;
    white-space: nowrap;
}

.toolbar__controls {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 8px;
}

.button,
.slider-control {
    min-height: 26px;
    border: 1px solid var(--border);
    border-radius: 12px;
    background: var(--surface);
    color: var(--text);
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 26px;
    padding: 0 16px;
    border-color: var(--button-border);
    border-radius: 14px;
    background: var(--button-bg);
    color: var(--button-text);
    font-size: 0.95rem;
    font-weight: 500;
    letter-spacing: 0;
    line-height: 1;
    text-transform: none;
    transition:
        border-color 160ms ease,
        background-color 160ms ease,
        color 160ms ease,
        box-shadow 160ms ease,
        transform 80ms ease;
}

.button:hover,
.button:focus-visible {
    border-color: var(--border-strong);
    background: var(--button-bg-hover);
    outline: none;
}

.button:focus-visible {
    box-shadow:
        0 0 0 1px var(--background),
        0 0 0 3px var(--border);
}

.button:active {
    transform: translateY(1px);
}

.button--primary {
    border-color: var(--accent-border);
    box-shadow: inset 0 0 0 1px var(--accent-border);
}

.slider-control {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 0 10px;
    color: var(--muted);
    font-size: 0.79rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.slider-control span,
.slider-control output {
    white-space: nowrap;
}

.slider-control input {
    width: 130px;
    accent-color: var(--accent);
}

.workspace {
    display: grid;
    gap: 10px;
    margin-top: 0px;
}

.workspace__hint {
    margin: 0;
    color: var(--muted);
    text-align: center;
    font-size: 12px;
    letter-spacing: auto;
    border: 1px solid var(--accent-border);
    border-radius: 0 0 4px 4px;
    padding: 4px;
    border-top: 0;
    width: 600px;
    margin: auto;
}

.comparison-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
    min-height: calc(100vh - 166px);
}

.pane {
    position: relative;
    min-height: 100%;
    padding: 10px;
    border: 0px solid var(--border);
    border-radius: var(--radius);
    background: var(--surface);
    transition:
        border-color 160ms ease,
        background-color 160ms ease;
}

.pane--active {
    border-color: var(--accent-border-strong);
}

.pane--active .pane__surface {
    border-color: seagreen;
}

.pane--dragging {
    border-color: var(--accent-border-strong);
    background: var(--surface-lift);
}

.pane__surface {
    position: relative;
    display: grid;
    place-items: center;
    min-height: 100%;
    padding: calc(var(--pane-padding) + 22px) var(--pane-padding)
        var(--pane-padding);
    overflow: hidden;
    border: 1px dashed var(--border-strong);
    border-radius: var(--radius-sm);
    background: var(--surface-image);
}

.pane__surface:has(.pane__image:not([hidden])) {
    border: 1px solid transparent;
    background: var(--surface-image);
}

.pane__surface:has(.pane__image:not([hidden])) .pane__empty {
    display: none;
}

.pane__label-wrap {
    position: absolute;
    top: 14px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 3;
    display: flex;
    align-items: center;
    justify-content: center;
}

.pane__label {
    min-width: 0;
    max-width: 100%;
    padding: 4px 12px;
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-sm);
    background: var(--surface);
    color: var(--text);
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.09em;
    outline: none;
}

.pane__label:focus {
    border-color: var(--accent-border-strong);
    background: var(--card-soft);
}

.pane__image {
    display: block;
    width: 100%;
    height: 100%;
    max-width: 100%;
    max-height: calc(100vh - 270px);
    object-fit: contain;
    object-position: center;
    user-select: none;
    border: 1px solid transparent;
}

.pane__empty {
    display: grid;
    place-items: center;
    gap: 6px;
    text-align: center;
    color: var(--muted);
    text-transform: uppercase;
}

.pane__empty p,
.pane__empty span {
    margin: 0;
}

.pane__empty p {
    color: var(--text);
    font-weight: 700;
}

body.ui-hidden [data-ui] {
    display: none !important;
}

body.ui-hidden .app-shell {
    margin: 0;
    width: 100vw;
    min-height: 100vh;
    border-radius: 0;
}

body.ui-hidden .comparison-grid {
    min-height: calc(100vh - 36px);
    gap: 0;
}

body.ui-hidden .pane {
    padding: 0;
    border-color: transparent;
    border-radius: 0;
    background: transparent;
}

body.ui-hidden .pane__surface {
    min-height: calc(100vh - 36px);
    border-color: transparent;
    border-radius: 0;
}

body.ui-hidden .pane--active,
body.ui-hidden .pane--dragging {
    border-color: transparent;
}

kbd {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 1.45rem;
    min-height: 1.45rem;
    padding: 0 0.35rem;
    border: 1px solid var(--kbd-border);
    border-radius: 0.5rem;
    background: var(--kbd-bg);
    color: var(--kbd-text);
    box-shadow: var(--kbd-shadow);
    font-size: 0.92em;
    font-weight: 600;
    line-height: 1;
}

@media (max-width: 980px) {
    .comparison-grid {
        grid-template-columns: 1fr;
    }

    .pane__surface {
        min-height: 360px;
    }

    .toolbar__controls {
        justify-content: flex-start;
    }
}

@media (max-width: 680px) {
    .app-shell {
        width: 100%;
        margin: 0;
        min-height: 100vh;
        padding: 10px;
    }

    .toolbar__controls {
        width: 100%;
    }

    .slider-control {
        width: 100%;
        justify-content: space-between;
    }

    .slider-control input {
        width: 100%;
        max-width: 170px;
    }

    .button {
        flex: 1 1 calc(50% - 8px);
    }
}