/* ==========================================
   NegaToPos — Darkroom lab identity
   Amber safelight + charcoal + silver halide
   ========================================== */

:root {
    --bg: #100e0c;
    --bg-raised: #181410;
    --bg-panel: #1c1813;
    --bg-hover: #262019;
    --ink: #f3ece2;
    --ink-soft: #cbbfaf;
    --ink-muted: #8f8476;
    --line: rgba(243, 236, 226, 0.1);
    --line-strong: rgba(232, 164, 92, 0.45);
    --amber: #e8a45c;
    --amber-deep: #c46b2e;
    --amber-soft: rgba(232, 164, 92, 0.14);
    --danger: #e07060;
    --ok: #9bbb7a;
    --warn: #d4b05a;

    --font-display: "Cormorant Garamond", "Times New Roman", serif;
    --font-ui: "IBM Plex Sans", "Segoe UI", sans-serif;

    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.5rem;
    --space-6: 2rem;
    --space-7: 3rem;
    --space-8: 4rem;

    --radius: 4px;
    --radius-md: 8px;
    --shadow-soft: 0 18px 50px rgba(0, 0, 0, 0.35);
    --focus: 0 0 0 2px var(--bg), 0 0 0 4px var(--amber);

    --header-h: 4.25rem;
    --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

body {
    min-height: 100vh;
    font-family: var(--font-ui);
    color: var(--ink);
    background:
        radial-gradient(ellipse 90% 55% at 10% -10%, rgba(196, 107, 46, 0.16), transparent 55%),
        radial-gradient(ellipse 70% 45% at 100% 100%, rgba(232, 164, 92, 0.07), transparent 50%),
        var(--bg);
    display: flex;
    flex-direction: column;
    line-height: 1.5;
}

img, canvas {
    max-width: 100%;
    display: block;
}

button, input {
    font: inherit;
    color: inherit;
}

:focus-visible {
    outline: none;
    box-shadow: var(--focus);
}

.skip-link {
    position: absolute;
    left: var(--space-4);
    top: -4rem;
    z-index: 200;
    background: var(--amber);
    color: #1a120a;
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius);
    text-decoration: none;
    font-weight: 600;
}

.skip-link:focus {
    top: var(--space-4);
}

/* Header */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    border-bottom: 1px solid var(--line);
    background: rgba(16, 14, 12, 0.92);
    backdrop-filter: blur(8px);
}

.header-inner {
    max-width: 1200px;
    margin: 0 auto;
    min-height: var(--header-h);
    padding: var(--space-3) var(--space-5);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-4);
}

.brand {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    text-decoration: none;
    color: inherit;
}

.brand-mark {
    width: 2.25rem;
    height: 2.25rem;
    flex-shrink: 0;
}

.brand-text {
    display: flex;
    flex-direction: column;
    gap: 0.1rem;
}

.brand-name {
    font-family: var(--font-display);
    font-size: 1.65rem;
    font-weight: 600;
    letter-spacing: 0.01em;
    line-height: 1;
}

.brand-tag {
    font-size: 0.72rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--ink-muted);
}

.privacy-chip {
    font-size: 0.78rem;
    color: var(--ink-soft);
    border: 1px solid var(--line);
    padding: 0.35rem 0.7rem;
    border-radius: var(--radius);
    background: var(--bg-raised);
}

.privacy-chip strong {
    color: var(--amber);
    font-weight: 600;
}

/* Main */
.site-main {
    flex: 1;
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-6) var(--space-5) var(--space-7);
}

.section {
    animation: rise 420ms var(--ease);
}

@keyframes rise {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: none; }
}

/* Upload */
.upload-hero {
    display: grid;
    gap: var(--space-5);
    max-width: 40rem;
    margin: 0 auto;
    padding-top: clamp(1rem, 6vh, 3.5rem);
}

.upload-kicker {
    font-size: 0.78rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--amber);
}

.upload-hero h1 {
    font-family: var(--font-display);
    font-weight: 600;
    font-size: clamp(2.4rem, 6vw, 3.6rem);
    line-height: 1.05;
    letter-spacing: -0.02em;
}

.upload-lead {
    color: var(--ink-soft);
    font-size: 1.05rem;
    max-width: 34rem;
}

.dropzone {
    margin-top: var(--space-2);
    border: 1px dashed rgba(232, 164, 92, 0.35);
    background: linear-gradient(180deg, rgba(232, 164, 92, 0.05), transparent 55%), var(--bg-panel);
    border-radius: var(--radius-md);
    padding: clamp(2rem, 5vw, 3rem) var(--space-5);
    text-align: center;
    cursor: pointer;
    transition: border-color 200ms ease, transform 200ms var(--ease), background 200ms ease;
    box-shadow: var(--shadow-soft);
}

.dropzone:hover,
.dropzone.is-dragover {
    border-color: var(--amber);
    transform: translateY(-2px);
    background: linear-gradient(180deg, rgba(232, 164, 92, 0.1), transparent 55%), var(--bg-panel);
}

.dropzone-icon {
    width: 3rem;
    height: 3rem;
    margin: 0 auto var(--space-4);
    color: var(--amber);
}

.dropzone h2 {
    font-family: var(--font-display);
    font-size: 1.7rem;
    font-weight: 600;
    margin-bottom: var(--space-2);
}

.dropzone p {
    color: var(--ink-muted);
    font-size: 0.95rem;
}

.dropzone-formats {
    margin-top: var(--space-2);
    margin-bottom: var(--space-5);
    font-size: 0.82rem !important;
}

.hint-row {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
    color: var(--ink-muted);
    font-size: 0.85rem;
}

.hint-row span {
    border-left: 2px solid var(--amber-soft);
    padding-left: var(--space-3);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    min-height: 2.75rem;
    padding: 0.65rem 1.15rem;
    border-radius: var(--radius);
    border: 1px solid transparent;
    cursor: pointer;
    font-weight: 600;
    letter-spacing: 0.01em;
    transition: background 160ms ease, border-color 160ms ease, color 160ms ease, transform 160ms ease;
}

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

.btn-primary {
    background: linear-gradient(180deg, #efb06d, var(--amber-deep));
    color: #1a120a;
}

.btn-primary:hover {
    filter: brightness(1.05);
}

.btn-secondary {
    background: var(--bg-hover);
    border-color: var(--line);
    color: var(--ink);
}

.btn-secondary:hover {
    border-color: var(--line-strong);
}

.btn-ghost {
    background: transparent;
    border-color: var(--line);
    color: var(--ink-soft);
}

.btn-ghost:hover {
    color: var(--ink);
    border-color: var(--line-strong);
    background: var(--amber-soft);
}

.btn-ghost.is-active,
.btn-accent.is-active {
    border-color: var(--amber);
    color: var(--amber);
    background: var(--amber-soft);
}

.btn-accent {
    width: 100%;
    background: var(--bg-raised);
    border: 1px solid var(--line);
    color: var(--ink-soft);
    border-radius: var(--radius);
}

.btn-block {
    width: 100%;
}

/* Editor */
.editor-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: var(--space-5);
    align-items: start;
}

.preview-col {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    min-width: 0;
}

.preview-toolbar {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-3);
}

.tabs {
    display: inline-flex;
    gap: 2px;
    padding: 3px;
    background: var(--bg-panel);
    border: 1px solid var(--line);
    border-radius: var(--radius);
}

.tab {
    appearance: none;
    border: 0;
    background: transparent;
    color: var(--ink-muted);
    padding: 0.55rem 0.9rem;
    min-height: 2.5rem;
    border-radius: 3px;
    cursor: pointer;
    font-size: 0.88rem;
    font-weight: 500;
}

.tab.is-active {
    background: var(--amber-soft);
    color: var(--ink);
}

.image-count {
    font-size: 0.82rem;
    color: var(--ink-muted);
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.preview-frame {
    position: relative;
    min-height: min(62vh, 560px);
    background:
        linear-gradient(45deg, #17130f 25%, transparent 25%),
        linear-gradient(-45deg, #17130f 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #17130f 75%),
        linear-gradient(-45deg, transparent 75%, #17130f 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0;
    background-color: #120f0c;
    border: 1px solid var(--line);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.preview-split {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    min-height: inherit;
    position: relative;
    padding: var(--space-3);
}

/* Same-size stacked canvases + clip-path = real before/after reveal */
.compare-stack {
    position: relative;
    display: inline-block;
    max-width: 100%;
    line-height: 0;
    --split: 50%;
}

.compare-stack #canvas-result {
    position: relative;
    z-index: 1;
    display: block;
    max-width: 100%;
    max-height: min(62vh, 560px);
    width: auto;
    height: auto;
}

.compare-stack #canvas-original {
    position: absolute;
    inset: 0;
    z-index: 2;
    width: 100%;
    height: 100%;
    clip-path: inset(0 calc(100% - var(--split)) 0 0);
}

/* Eyedropper: custom cursor on the whole compare surface */
.preview-frame.is-eyedropper,
.preview-frame.is-eyedropper .compare-stack,
.preview-frame.is-eyedropper .compare-stack canvas {
    cursor: url("../assets/cursor-eyedropper.png") 5 28, crosshair !important;
}

.preview-frame.is-eyedropper .split-divider {
    pointer-events: none;
}

.preview-split[data-mode="original"] #canvas-result,
.preview-split[data-mode="result"] #canvas-original,
.preview-split[data-mode="original"] .split-divider,
.preview-split[data-mode="result"] .split-divider,
.preview-split[data-mode="original"] .label-pos,
.preview-split[data-mode="result"] .label-neg {
    display: none !important;
}

.preview-split[data-mode="original"] #canvas-original {
    position: relative;
    inset: auto;
    clip-path: none;
    max-width: 100%;
    max-height: min(62vh, 560px);
    width: auto;
    height: auto;
}

.preview-label {
    position: absolute;
    bottom: var(--space-3);
    z-index: 4;
    font-size: 0.68rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--ink);
    background: rgba(16, 14, 12, 0.78);
    border: 1px solid var(--line);
    padding: 0.3rem 0.55rem;
    border-radius: var(--radius);
    pointer-events: none;
}

.label-neg {
    left: var(--space-3);
}

.label-pos {
    right: var(--space-3);
    left: auto;
}

.split-divider {
    position: absolute;
    top: 0;
    bottom: 0;
    left: var(--split);
    width: 2px;
    transform: translateX(-50%);
    background: var(--amber);
    z-index: 5;
    cursor: col-resize;
    touch-action: none;
}

.split-divider[hidden] {
    display: none !important;
}

.split-handle {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 2rem;
    height: 2.75rem;
    transform: translate(-50%, -50%);
    border: 1px solid rgba(26, 18, 10, 0.35);
    border-radius: var(--radius);
    background: linear-gradient(180deg, #efb06d, var(--amber-deep));
    display: grid;
    place-items: center;
    color: #1a120a;
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.35);
}

.split-divider.is-dragging .split-handle {
    transform: translate(-50%, -50%) scale(1.05);
}

.processing-overlay {
    position: absolute;
    inset: 0;
    z-index: 8;
    display: grid;
    place-items: center;
    gap: var(--space-3);
    background: rgba(16, 14, 12, 0.72);
}

.processing-overlay[hidden] {
    display: none !important;
}

.film-progress {
    width: min(220px, 60%);
    height: 3px;
    background: rgba(243, 236, 226, 0.12);
    overflow: hidden;
    border-radius: 999px;
}

.film-progress::after {
    content: "";
    display: block;
    width: 40%;
    height: 100%;
    background: var(--amber);
    animation: scan 1s var(--ease) infinite;
}

@keyframes scan {
    from { transform: translateX(-120%); }
    to { transform: translateX(280%); }
}

.processing-overlay p {
    color: var(--ink-soft);
    font-size: 0.9rem;
}

.thumb-strip {
    display: flex;
    gap: var(--space-2);
    overflow-x: auto;
    padding-bottom: var(--space-1);
    scrollbar-width: thin;
}

.thumb-strip:empty {
    display: none;
}

.thumb {
    flex: 0 0 auto;
    width: 4.25rem;
    height: 4.25rem;
    padding: 0;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    overflow: hidden;
    opacity: 0.65;
    cursor: pointer;
    background: var(--bg-panel);
}

.thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.thumb:hover,
.thumb.is-active {
    opacity: 1;
    border-color: var(--amber);
}

/* Controls */
.controls {
    background: var(--bg-panel);
    border: 1px solid var(--line);
    border-radius: var(--radius-md);
    padding: var(--space-5);
    display: flex;
    flex-direction: column;
    gap: var(--space-5);
    position: sticky;
    top: calc(var(--header-h) + var(--space-3));
}

.controls h2 {
    font-family: var(--font-display);
    font-size: 1.55rem;
    font-weight: 600;
}

.control-block {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.control-label {
    font-size: 0.78rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--ink-muted);
}

.segmented {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-2);
}

.segmented-wide {
    grid-template-columns: repeat(2, 1fr);
}

@media (min-width: 360px) {
    .segmented-wide {
        grid-template-columns: repeat(4, 1fr);
    }
}

.seg-btn {
    min-height: 2.5rem;
    border: 1px solid var(--line);
    background: var(--bg-raised);
    color: var(--ink-soft);
    border-radius: var(--radius);
    cursor: pointer;
    font-size: 0.82rem;
    font-weight: 500;
    padding: 0.4rem;
}

.seg-btn.is-active {
    border-color: var(--amber);
    color: var(--ink);
    background: var(--amber-soft);
}

.slider-head {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: var(--space-3);
}

.slider-head label {
    font-size: 0.9rem;
    color: var(--ink-soft);
}

.slider-val {
    font-variant-numeric: tabular-nums;
    font-size: 0.82rem;
    color: var(--amber);
    min-width: 2.25rem;
    text-align: right;
}

.slider {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 4px;
    border-radius: 999px;
    background: var(--bg-hover);
    outline: none;
}

.slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 1.1rem;
    height: 1.1rem;
    border-radius: 50%;
    background: var(--amber);
    border: 2px solid #1a120a;
    cursor: pointer;
}

.slider::-moz-range-thumb {
    width: 1.1rem;
    height: 1.1rem;
    border-radius: 50%;
    background: var(--amber);
    border: 2px solid #1a120a;
    cursor: pointer;
}

.actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-2);
}

.actions .btn {
    min-width: 0;
}

.stack-actions {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.kbd-hint {
    font-size: 0.75rem;
    color: var(--ink-muted);
    line-height: 1.45;
}

.kbd-hint kbd {
    font-family: var(--font-ui);
    font-size: 0.7rem;
    border: 1px solid var(--line);
    border-radius: 3px;
    padding: 0.05rem 0.3rem;
    background: var(--bg-raised);
}

/* Toast */
.toast {
    position: fixed;
    left: 50%;
    bottom: var(--space-5);
    transform: translate(-50%, 120%);
    z-index: 100;
    max-width: min(92vw, 28rem);
    padding: 0.85rem 1.15rem;
    background: var(--bg-raised);
    border: 1px solid var(--line);
    border-radius: var(--radius-md);
    color: var(--ink);
    font-size: 0.92rem;
    box-shadow: var(--shadow-soft);
    opacity: 0;
    pointer-events: none;
    transition: transform 280ms var(--ease), opacity 280ms ease;
}

.toast.show {
    opacity: 1;
    transform: translate(-50%, 0);
}

.toast[data-tone="error"] {
    border-color: rgba(224, 112, 96, 0.55);
}

.toast[data-tone="warn"] {
    border-color: rgba(212, 176, 90, 0.55);
}

/* Footer */
.site-footer {
    border-top: 1px solid var(--line);
    padding: var(--space-5);
    text-align: center;
    color: var(--ink-muted);
    font-size: 0.82rem;
}

.site-footer a {
    color: var(--amber);
}

/* Responsive */
@media (max-width: 960px) {
    .editor-layout {
        grid-template-columns: 1fr;
    }

    .controls {
        position: static;
        order: 2;
    }

    .preview-col {
        order: 1;
    }
}

@media (max-width: 640px) {
    .header-inner {
        padding: var(--space-3) var(--space-4);
    }

    .privacy-chip {
        display: none;
    }

    .site-main {
        padding: var(--space-5) var(--space-4) var(--space-6);
    }

    .tabs {
        width: 100%;
    }

    .tab {
        flex: 1;
        text-align: center;
        padding-inline: 0.4rem;
        font-size: 0.8rem;
    }

    .preview-frame {
        min-height: 42vh;
    }

    .compare-stack #canvas-result,
    .preview-split[data-mode="original"] #canvas-original {
        max-height: 48vh;
    }

    .actions {
        grid-template-columns: 1fr;
    }

    .btn {
        min-height: 2.85rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}