:root {
  color-scheme: light dark;
  --bg: #f2f1ed;
  --panel: #ffffff;
  --text: #252525;
  --muted: #6b6b68;
  --border: #d7d5cf;
  --accent: #355d48;
  --accent-hover: #294b39;
  --accent-soft: #e5eee8;
  --warning: #8a4b0f;
  --warning-bg: #fff0dd;
  --upscale: #7b3e11;
  --upscale-bg: #fff0df;
  --error: #9e2929;
  --error-bg: #fff0f0;
  --checker-a: #ececec;
  --checker-b: #dcdcdc;
  --shadow: 0 12px 30px rgba(0, 0, 0, 0.07);
}

* {
  box-sizing: border-box;
}

html {
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
}

body {
  margin: 0;
  min-width: 320px;
}

button,
input,
select {
  font: inherit;
}

button,
select,
input[type="number"] {
  min-height: 44px;
}

.app-shell {
  width: min(1100px, calc(100% - 32px));
  margin: 0 auto;
  padding: 48px 0 32px;
}

.site-header {
  max-width: 780px;
  margin-bottom: 28px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 12px;
  font-size: clamp(2rem, 5vw, 3.6rem);
  line-height: 1;
  letter-spacing: -0.04em;
}

h2 {
  margin-bottom: 8px;
  font-size: 1.25rem;
}

h3 {
  margin-bottom: 10px;
  font-size: 0.95rem;
}

.intro,
.section-heading p,
.site-footer,
.metric-detail {
  color: var(--muted);
}

.panel {
  margin-bottom: 20px;
  padding: 24px;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.section-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.section-heading p {
  margin-bottom: 0;
}

.drop-zone {
  display: flex;
  min-height: 220px;
  margin-top: 20px;
  padding: 28px;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 6px;
  border: 2px dashed var(--border);
  border-radius: 14px;
  background: color-mix(in srgb, var(--panel) 90%, var(--accent-soft));
  cursor: pointer;
  text-align: center;
  transition: border-color 160ms ease, background-color 160ms ease;
}

.drop-zone:hover,
.drop-zone.is-dragging {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.drop-zone input {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  opacity: 0;
}

.drop-zone-title {
  font-size: 1.2rem;
  font-weight: 700;
}

.drop-zone-subtitle,
.drop-zone-types {
  color: var(--muted);
}

.drop-zone-types {
  margin-top: 10px;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.workspace[hidden],
[hidden] {
  display: none !important;
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  margin: 20px 0;
}

.metric {
  display: flex;
  min-height: 110px;
  padding: 16px;
  flex-direction: column;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: color-mix(in srgb, var(--panel) 95%, var(--bg));
}

.metric-label {
  margin-bottom: 5px;
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
}

.metric strong {
  font-size: 1.1rem;
}

.metric-detail {
  margin-top: 4px;
  font-size: 0.82rem;
}

.scale-banner {
  margin: 16px 0 22px;
  padding: 12px 16px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 800;
  letter-spacing: 0.02em;
  text-align: center;
}

.scale-banner.is-upscaled {
  background: var(--upscale-bg);
  color: var(--upscale);
}

.controls-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
  align-items: end;
  gap: 16px;
}

.control-group {
  display: flex;
  min-width: 0;
  flex-direction: column;
  gap: 7px;
}

.control-group label {
  font-size: 0.86rem;
  font-weight: 700;
}

input[type="number"],
select {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: var(--panel);
  color: var(--text);
}

input:focus,
select:focus,
button:focus-visible,
.drop-zone:focus-within {
  outline: 3px solid color-mix(in srgb, var(--accent) 30%, transparent);
  outline-offset: 2px;
}

.ratio-lock {
  display: flex;
  min-width: 120px;
  padding-bottom: 6px;
  align-items: center;
  flex-direction: column;
  color: var(--muted);
  font-size: 0.76rem;
}

.ratio-lock strong {
  color: var(--text);
}

.ratio-line {
  width: 28px;
  height: 1px;
  margin-bottom: 5px;
  background: var(--border);
}

.scale-controls {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 16px;
  margin-top: 18px;
  align-items: end;
}

.input-suffix {
  display: flex;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: var(--panel);
  overflow: hidden;
}

.input-suffix input {
  min-width: 0;
  border: 0;
  border-radius: 0;
}

.input-suffix span {
  padding-right: 12px;
  color: var(--muted);
}

.preset-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.preset-buttons button {
  min-height: 40px;
  padding: 8px 13px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--panel);
  color: var(--text);
  cursor: pointer;
}

.preset-buttons button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.export-controls {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2fr);
  gap: 16px;
  margin: 18px 0 24px;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}

.preview-layout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.preview-frame {
  display: flex;
  min-height: 320px;
  padding: 14px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}

.checkerboard {
  background-color: var(--checker-a);
  background-image:
    linear-gradient(45deg, var(--checker-b) 25%, transparent 25%),
    linear-gradient(-45deg, var(--checker-b) 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, var(--checker-b) 75%),
    linear-gradient(-45deg, transparent 75%, var(--checker-b) 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0;
}

.preview-frame img,
.preview-frame canvas {
  display: block;
  max-width: 100%;
  max-height: 440px;
  width: auto;
  height: auto;
  object-fit: contain;
}

.export-summary {
  display: flex;
  margin-top: 20px;
  padding-top: 18px;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-top: 1px solid var(--border);
}

.export-summary div {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.export-summary span {
  color: var(--muted);
  font-size: 0.82rem;
}

.button {
  padding: 10px 16px;
  border-radius: 9px;
  border: 1px solid transparent;
  cursor: pointer;
  font-weight: 700;
}

.button-primary {
  background: var(--accent);
  color: #fff;
}

.button-primary:hover {
  background: var(--accent-hover);
}

.button-secondary {
  border-color: var(--border);
  background: transparent;
  color: var(--text);
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

.message {
  margin: 14px 0 0;
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 0.9rem;
}

.message-error {
  background: var(--error-bg);
  color: var(--error);
}

.message-info {
  background: var(--accent-soft);
  color: var(--accent);
}

.site-footer {
  padding: 8px 4px 0;
  font-size: 0.85rem;
}

.site-footer p {
  margin-bottom: 0;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #151716;
    --panel: #1e211f;
    --text: #eceeea;
    --muted: #a9ada8;
    --border: #3d423e;
    --accent: #81b899;
    --accent-hover: #9bc9ad;
    --accent-soft: #22372b;
    --upscale: #f0b174;
    --upscale-bg: #3a291b;
    --error: #ff9898;
    --error-bg: #3a2020;
    --checker-a: #242724;
    --checker-b: #333833;
    --shadow: none;
  }

  .button-primary {
    color: #102117;
  }
}

@media (max-width: 820px) {
  .metrics-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .preview-frame {
    min-height: 240px;
  }
}

@media (max-width: 620px) {
  .app-shell {
    width: min(100% - 20px, 1100px);
    padding-top: 28px;
  }

  .panel {
    padding: 18px;
    border-radius: 12px;
  }

  .section-heading,
  .export-summary {
    align-items: stretch;
    flex-direction: column;
  }

  .controls-grid,
  .scale-controls,
  .export-controls,
  .preview-layout {
    grid-template-columns: 1fr;
  }

  .ratio-lock {
    min-width: 0;
    padding: 0;
    flex-direction: row;
    justify-content: center;
    gap: 7px;
  }

  .ratio-line {
    display: none;
  }

  .preview-frame {
    min-height: 210px;
  }

  .button-primary {
    width: 100%;
  }
}