:root {
  color-scheme: light;
  --paper: #f3eddf;
  --paper-deep: #e7ddca;
  --ink: #171815;
  --muted: #67665f;
  --line: #c8bea9;
  --white: #fffdf6;
  --yellow: #f0c62e;
  --red: #d84a38;
  --blue: #3366b1;
  --green: #39855b;
  --shadow: 0 14px 38px rgba(59, 48, 28, 0.1);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 8%, rgba(240, 198, 46, 0.16), transparent 28rem),
    radial-gradient(circle at 90% 28%, rgba(51, 102, 177, 0.1), transparent 32rem),
    var(--paper);
}

button,
input {
  font: inherit;
}

button:focus-visible,
input:focus-visible {
  outline: 3px solid rgba(51, 102, 177, 0.36);
  outline-offset: 3px;
}

code {
  padding: 0.12rem 0.35rem;
  border: 1px solid rgba(23, 24, 21, 0.12);
  border-radius: 0.3rem;
  background: rgba(255, 255, 255, 0.45);
  font-size: 0.87em;
}

.page-shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 38px 0 30px;
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 180px;
  gap: 48px;
  align-items: end;
  padding: 34px 38px 38px;
  overflow: hidden;
  border: 1px solid var(--ink);
  border-radius: 28px;
  background: var(--white);
  box-shadow: var(--shadow);
}

.hero::after {
  position: absolute;
  right: -70px;
  bottom: -85px;
  width: 280px;
  height: 280px;
  border: 1px solid var(--line);
  border-radius: 50%;
  content: "";
}

.eyebrow,
.step-label {
  margin: 0 0 8px;
  color: var(--red);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

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

h1 {
  margin-bottom: 20px;
  font-size: clamp(2.6rem, 7vw, 5.7rem);
  font-weight: 850;
  letter-spacing: -0.065em;
  line-height: 0.86;
}

h2 {
  margin-bottom: 0;
  font-size: clamp(1.15rem, 2vw, 1.55rem);
  letter-spacing: -0.025em;
}

.hero-copy {
  max-width: 670px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.7;
}

.color-bars {
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  height: 126px;
  transform: rotate(-4deg);
}

.color-bars span {
  border: 1px solid var(--ink);
  border-radius: 999px;
}

.color-bars span:nth-child(1) { background: #141414; }
.color-bars span:nth-child(2) { background: #fff; }
.color-bars span:nth-child(3) { background: var(--yellow); }
.color-bars span:nth-child(4) { background: var(--red); }
.color-bars span:nth-child(5) { background: var(--blue); }
.color-bars span:nth-child(6) { background: var(--green); }

main {
  display: grid;
  gap: 18px;
  margin-top: 18px;
}

.panel {
  border: 1px solid var(--line);
  border-radius: 22px;
  background: rgba(255, 253, 246, 0.88);
  box-shadow: 0 8px 26px rgba(59, 48, 28, 0.06);
  backdrop-filter: blur(14px);
}

.preflight-panel {
  padding: 26px 30px;
}

.section-heading,
.step-title-row {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  justify-content: space-between;
}

.section-heading.compact {
  align-items: center;
}

.status-pill,
.step-state {
  flex: 0 0 auto;
  padding: 0.38rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  background: var(--paper);
  font-size: 0.75rem;
  font-weight: 750;
}

.status-pill.success,
.step-state.success {
  border-color: rgba(57, 133, 91, 0.5);
  color: #1f6540;
  background: #e5f2e9;
}

.status-pill.error,
.step-state.error {
  border-color: rgba(216, 74, 56, 0.45);
  color: #a82f23;
  background: #f8e6e1;
}

.status-pill.working,
.step-state.working {
  border-color: rgba(51, 102, 177, 0.45);
  color: #28548f;
  background: #e6edf8;
}

.status-pill.warning,
.step-state.warning {
  border-color: rgba(240, 198, 46, 0.65);
  color: #705c12;
  background: #faf3d4;
}

.check-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: 24px;
}

.check-item {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  min-height: 82px;
  padding: 15px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.38);
}

.check-item strong {
  display: block;
  margin-bottom: 4px;
  font-size: 0.88rem;
}

.check-item p {
  margin: 0;
  color: var(--muted);
  font-size: 0.79rem;
  line-height: 1.45;
}

.indicator {
  width: 11px;
  height: 11px;
  margin-top: 4px;
  border: 1px solid var(--muted);
  border-radius: 50%;
  background: var(--paper-deep);
}

.indicator.success {
  border-color: var(--green);
  background: var(--green);
  box-shadow: 0 0 0 4px rgba(57, 133, 91, 0.12);
}

.indicator.error {
  border-color: var(--red);
  background: var(--red);
  box-shadow: 0 0 0 4px rgba(216, 74, 56, 0.12);
}

.notice {
  display: none;
  margin-top: 16px;
  padding: 13px 15px;
  border-left: 4px solid var(--blue);
  border-radius: 7px;
  color: #284567;
  background: #e8eef6;
  font-size: 0.88rem;
  line-height: 1.55;
}

.notice.visible {
  display: block;
}

.notice.error {
  border-left-color: var(--red);
  color: #7f2e25;
  background: #f7e8e4;
}

.workflow {
  display: grid;
  gap: 12px;
}

.step-card {
  display: grid;
  grid-template-columns: 92px minmax(0, 1fr);
  min-height: 240px;
  overflow: hidden;
}

.step-number {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 28px;
  border-right: 1px solid var(--line);
  color: var(--ink);
  background: var(--paper-deep);
  font-size: 1.6rem;
  font-weight: 850;
  letter-spacing: -0.06em;
}

.step-card[data-step="pair"] .step-number { background: #f3dfd8; }
.step-card[data-step="probe"] .step-number { background: #dce6f2; }
.step-card[data-step="send"] .step-number { background: #eadfba; }

.step-content {
  padding: 27px 30px 30px;
}

.step-content > p {
  max-width: 780px;
  margin: 18px 0 0;
  color: var(--muted);
  line-height: 1.65;
}

.checkbox-row {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  width: fit-content;
  margin-top: 18px;
  cursor: pointer;
}

.checkbox-row input {
  width: 18px;
  height: 18px;
  margin-top: 2px;
  accent-color: var(--blue);
}

.checkbox-row strong,
.checkbox-row small {
  display: block;
}

.checkbox-row small {
  margin-top: 3px;
  color: var(--muted);
  line-height: 1.45;
}

.physical-action {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px;
  align-items: start;
  max-width: 820px;
  margin-top: 18px;
  padding: 14px 16px;
  border: 1px solid rgba(216, 74, 56, 0.28);
  border-radius: 12px;
  background: rgba(216, 74, 56, 0.07);
}

.physical-action span {
  padding: 0.22rem 0.48rem;
  border-radius: 5px;
  color: #fff;
  background: var(--red);
  font-size: 0.7rem;
  font-weight: 800;
}

.physical-action p {
  margin: 0;
  color: #74342c;
  font-size: 0.88rem;
  line-height: 1.6;
}

.destructive-warning {
  margin-top: 0;
  border-color: rgba(216, 74, 56, 0.5);
  background: rgba(216, 74, 56, 0.1);
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 23px;
}

.capability-note {
  margin: 11px 0 0 !important;
  color: var(--muted);
  font-size: 0.76rem;
  line-height: 1.5;
}

.capability-note.warning {
  color: #9a4b24;
}

.button {
  min-height: 44px;
  padding: 0.68rem 1.05rem;
  border: 1px solid var(--ink);
  border-radius: 10px;
  font-weight: 750;
  cursor: pointer;
  transition: transform 120ms ease, box-shadow 120ms ease, opacity 120ms ease;
}

.button:not(:disabled):hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 14px rgba(23, 24, 21, 0.13);
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.42;
}

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

.button.secondary {
  color: var(--ink);
  background: var(--yellow);
}

.button.ghost {
  color: var(--ink);
  background: transparent;
}

.button.danger {
  border-color: #9f2c21;
  color: #fff;
  background: #b73529;
}

.image-workbench {
  display: grid;
  grid-template-columns: minmax(220px, 0.85fr) minmax(300px, 1.15fr);
  gap: 14px;
  margin-top: 24px;
}

.image-drop-zone,
.image-editor-controls {
  min-width: 0;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.42);
}

.image-drop-zone {
  display: grid;
  gap: 9px;
  align-content: center;
  border-style: dashed;
  cursor: pointer;
  transition: border-color 120ms ease, background 120ms ease;
}

.image-drop-zone:hover,
.image-drop-zone.dragging {
  border-color: var(--blue);
  background: rgba(51, 102, 177, 0.09);
}

.drop-zone-title {
  font-weight: 800;
}

.image-drop-zone small,
.focus-grid small,
.source-image-details,
.control-value {
  color: var(--muted);
  font-size: 0.76rem;
  line-height: 1.5;
}

.image-drop-zone input[type="file"] {
  width: 100%;
  margin-top: 5px;
  color: var(--muted);
  font-size: 0.76rem;
}

.image-drop-zone input[type="file"]::file-selector-button {
  margin-right: 10px;
  padding: 0.5rem 0.7rem;
  border: 1px solid var(--ink);
  border-radius: 8px;
  color: var(--white);
  background: var(--ink);
  font: inherit;
  font-weight: 750;
  cursor: pointer;
}

.image-editor-controls {
  display: grid;
  gap: 16px;
}

.editor-action-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

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

.focus-grid label,
.focus-grid label > span {
  display: grid;
  gap: 7px;
}

.focus-grid label > span {
  grid-template-columns: 1fr auto;
  color: var(--ink);
  font-size: 0.79rem;
}

.focus-grid input[type="range"] {
  width: 100%;
  margin: 0;
  accent-color: var(--blue);
}

.compact-row {
  margin-top: 0;
}

.source-image-details {
  margin: 0;
  overflow-wrap: anywhere;
}

.write-layout {
  display: grid;
  grid-template-columns: minmax(190px, 270px) minmax(0, 1fr);
  gap: 30px;
  align-items: start;
  margin-top: 24px;
}

.test-preview-card {
  margin: 0;
  padding: 12px;
  border: 1px solid var(--ink);
  border-radius: 16px;
  background: var(--white);
}

.test-preview-card canvas {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--ink);
  background: #fff;
  image-rendering: pixelated;
  transition: opacity 120ms ease;
}

.test-preview-card canvas.stale {
  opacity: 0.42;
}

.test-preview-card figcaption {
  margin-top: 10px;
  color: var(--muted);
  font-size: 0.73rem;
  line-height: 1.5;
}

.write-controls {
  min-width: 0;
}

.payload-details {
  margin: 18px 0 0;
  border-top: 1px solid var(--line);
}

.payload-details div {
  display: grid;
  grid-template-columns: 92px minmax(0, 1fr);
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
}

.payload-details dt {
  color: var(--muted);
  font-size: 0.76rem;
}

.payload-details dd {
  margin: 0;
  overflow-wrap: anywhere;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.72rem;
}

.confirmation-row {
  width: 100%;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.42);
}

.progress-stack {
  display: grid;
  gap: 8px;
  margin-top: 18px;
}

.progress-stack progress {
  width: 100%;
  height: 12px;
  overflow: hidden;
  border: 0;
  border-radius: 999px;
  color: var(--green);
  background: var(--paper-deep);
}

.progress-stack progress::-webkit-progress-bar {
  border-radius: 999px;
  background: var(--paper-deep);
}

.progress-stack progress::-webkit-progress-value {
  border-radius: 999px;
  background: var(--green);
}

.progress-stack progress::-moz-progress-bar {
  border-radius: 999px;
  background: var(--green);
}

.progress-stack span {
  color: var(--muted);
  font-size: 0.76rem;
}

.transfer-result {
  margin: 14px 0 0;
  padding: 12px 14px;
  border-left: 4px solid var(--line);
  border-radius: 7px;
  color: var(--muted);
  background: rgba(231, 221, 202, 0.58);
  font-size: 0.82rem;
  line-height: 1.55;
}

.transfer-result.success {
  border-left-color: var(--green);
  color: #1f6540;
  background: #e5f2e9;
}

.transfer-result.warning {
  border-left-color: var(--yellow);
  color: #705c12;
  background: #faf3d4;
}

.transfer-result.error {
  border-left-color: var(--red);
  color: #8d3026;
  background: #f8e6e1;
}

.result-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 12px;
}

.device-panel,
.log-panel {
  min-height: 410px;
  padding: 27px 30px;
}

.device-details {
  display: grid;
  gap: 0;
  margin: 22px 0 0;
}

.device-details div {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 16px;
  padding: 10px 0;
  border-bottom: 1px solid rgba(200, 190, 169, 0.7);
}

.device-details dt {
  color: var(--muted);
  font-size: 0.79rem;
}

.device-details dd {
  margin: 0;
  overflow-wrap: anywhere;
  font-size: 0.84rem;
  font-weight: 650;
}

.footnote {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 0.76rem;
  line-height: 1.5;
}

.inline-actions {
  display: flex;
  gap: 12px;
}

.text-button {
  padding: 0;
  border: 0;
  border-bottom: 1px solid currentColor;
  color: var(--blue);
  background: transparent;
  font-size: 0.78rem;
  font-weight: 700;
  cursor: pointer;
}

.event-log {
  height: 310px;
  margin: 20px 0 0;
  padding: 14px 14px 14px 42px;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 12px;
  color: #d6dfd2;
  background: #1d211e;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.76rem;
  line-height: 1.55;
}

.event-log:empty::before {
  color: #8b968d;
  content: "等待操作…";
}

.event-log li {
  padding: 3px 0;
  overflow-wrap: anywhere;
}

.event-log li::marker {
  color: #7f8b82;
}

.event-log .error { color: #ff9b8e; }
.event-log .success { color: #92d7a9; }
.event-log .warning { color: #f0d876; }

footer {
  display: flex;
  gap: 20px;
  justify-content: space-between;
  padding: 24px 4px 0;
  color: var(--muted);
  font-size: 0.76rem;
}

footer p {
  margin-bottom: 0;
}

@media (max-width: 800px) {
  .page-shell { width: min(100% - 20px, 680px); padding-top: 10px; }
  .hero { grid-template-columns: 1fr; gap: 28px; padding: 28px 24px; border-radius: 20px; }
  .color-bars { width: 180px; height: 70px; }
  .check-grid,
  .result-grid { grid-template-columns: 1fr; }
  .image-workbench { grid-template-columns: 1fr; }
  .write-layout { grid-template-columns: minmax(150px, 220px) minmax(0, 1fr); }
  .step-card { grid-template-columns: 58px minmax(0, 1fr); }
  .step-number { font-size: 1.15rem; }
  .step-content,
  .preflight-panel,
  .device-panel,
  .log-panel { padding: 22px 20px; }
}

@media (max-width: 520px) {
  .section-heading,
  .step-title-row { align-items: flex-start; }
  .check-grid { grid-template-columns: 1fr; }
  .step-card { display: block; }
  .step-number {
    justify-content: flex-start;
    padding: 12px 20px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
  .physical-action { grid-template-columns: 1fr; }
  .focus-grid { grid-template-columns: 1fr; }
  .write-layout { grid-template-columns: 1fr; }
  .test-preview-card { width: min(100%, 260px); }
  .device-details div { grid-template-columns: 95px 1fr; }
  footer { display: block; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}

/* User-facing v0.4 layout */
.user-shell {
  width: min(1040px, calc(100% - 32px));
}

.simple-hero {
  display: flex;
  gap: 28px;
  align-items: flex-end;
  justify-content: space-between;
  padding: 34px 38px;
  border: 1px solid var(--ink);
  border-radius: 26px;
  background: var(--white);
  box-shadow: var(--shadow);
}

.simple-hero h1 {
  margin: 0 0 18px;
  font-size: clamp(2.8rem, 7vw, 5.4rem);
  line-height: 0.9;
}

.simple-hero p:last-child {
  max-width: 620px;
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.mini-palette {
  display: grid;
  grid-template-columns: repeat(3, 44px);
  gap: 8px;
  flex: 0 0 auto;
}

.mini-palette i {
  width: 44px;
  height: 44px;
  border: 1px solid var(--ink);
  border-radius: 50%;
}

.mini-palette i:nth-child(1) { background: #000; }
.mini-palette i:nth-child(2) { background: #fff; }
.mini-palette i:nth-child(3) { background: #ffdf00; }
.mini-palette i:nth-child(4) { background: #e74632; }
.mini-palette i:nth-child(5) { background: #3269b6; }
.mini-palette i:nth-child(6) { background: #37885b; }

.simple-flow {
  display: grid;
  gap: 16px;
}

.user-step {
  padding: 28px 30px 30px;
}

.user-step-heading {
  display: flex;
  gap: 15px;
  align-items: center;
  margin-bottom: 24px;
}

.user-step-heading > span {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border: 1px solid var(--ink);
  border-radius: 50%;
  font-weight: 850;
}

.user-step-heading .step-label {
  margin-bottom: 3px;
}

.editor-layout {
  display: grid;
  grid-template-columns: minmax(240px, 330px) minmax(0, 1fr);
  gap: 28px;
  align-items: start;
  min-width: 0;
}

.live-preview-card {
  position: sticky;
  top: 14px;
  margin: 0;
}

.canvas-shell {
  position: relative;
  overflow: hidden;
  padding: 10px;
  border: 1px solid var(--ink);
  border-radius: 18px;
  background: var(--white);
  box-shadow: 0 12px 26px rgba(23, 24, 21, 0.09);
}

.canvas-shell canvas {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--ink);
  background: #fff;
  image-rendering: pixelated;
  touch-action: none;
  user-select: none;
}

.canvas-shell canvas.interactive {
  cursor: grab;
}

.canvas-shell canvas.interactive:active {
  cursor: grabbing;
}

.canvas-shell canvas.editing {
  image-rendering: auto;
}

.canvas-gesture-hint {
  position: absolute;
  right: 20px;
  bottom: 20px;
  padding: 0.4rem 0.58rem;
  border-radius: 7px;
  color: #fff;
  background: rgba(23, 24, 21, 0.76);
  font-size: 0.67rem;
  pointer-events: none;
  opacity: 0;
  transition: opacity 120ms ease;
}

.canvas-shell:has(canvas.interactive):hover .canvas-gesture-hint {
  opacity: 1;
}

.live-preview-card figcaption {
  margin-top: 10px;
  color: var(--muted);
  font-size: 0.76rem;
  line-height: 1.5;
}

.editor-panel,
.editor-tools {
  display: grid;
  gap: 16px;
  min-width: 0;
}

.image-source-box {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  padding: 18px;
  border: 1px dashed var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.42);
}

.image-source-box.dragging {
  border-color: var(--blue);
  background: rgba(51, 102, 177, 0.1);
}

.file-picker {
  display: inline-grid;
  place-items: center;
}

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

.paste-hint {
  flex-basis: 100%;
  color: var(--muted);
  font-size: 0.74rem;
}

.editor-tools {
  padding-top: 4px;
}

.tool-row {
  display: flex;
  gap: 14px;
  align-items: center;
}

.grow {
  flex: 1 1 auto;
}

.range-control,
.dither-card label {
  display: grid;
  gap: 8px;
}

.range-control > span,
.dither-card label > span {
  display: flex;
  gap: 10px;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.79rem;
}

.range-control input[type="range"] {
  width: 100%;
  margin: 0;
  accent-color: var(--blue);
}

.dither-card {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(160px, 0.8fr);
  gap: 16px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 13px;
  background: rgba(255, 255, 255, 0.42);
}

.dither-card select {
  width: 100%;
  min-width: 0;
  max-width: 100%;
  min-height: 42px;
  padding: 0 0.65rem;
  border: 1px solid var(--line);
  border-radius: 9px;
  color: var(--ink);
  background: var(--white);
  font: inherit;
}

.compact-details {
  border-top: 1px solid var(--line);
}

.compact-details summary {
  padding: 14px 0 4px;
  color: var(--blue);
  font-size: 0.78rem;
  font-weight: 750;
  cursor: pointer;
}

.compact-details .focus-grid {
  margin-top: 14px;
}

.connection-action,
.send-layout {
  display: flex;
  gap: 22px;
  align-items: center;
  justify-content: space-between;
}

.connection-action p {
  margin-bottom: 5px;
}

.connection-action small {
  color: var(--muted);
}

.connection-summary {
  font-weight: 760;
}

.connection-summary.success { color: #1f6540; }
.connection-summary.warning { color: #8d5426; }
.connection-summary.working { color: var(--blue); }

.large-button {
  min-height: 50px;
  padding-inline: 1.35rem;
}

.send-layout .confirmation-row {
  flex: 1 1 auto;
  margin-top: 0;
}

.diagnostics {
  overflow: hidden;
}

.diagnostics > summary {
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  cursor: pointer;
  font-weight: 800;
  list-style-position: inside;
}

.diagnostics > summary small {
  color: var(--muted);
  font-weight: 500;
}

.diagnostic-content {
  display: grid;
  gap: 26px;
  padding: 4px 28px 28px;
  border-top: 1px solid var(--line);
}

.diagnostic-content > section:first-child {
  padding-top: 24px;
}

.technical-actions {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.technical-step {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.diagnostic-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 28px;
}

.diagnostic-grid .event-log {
  height: 420px;
}

@media (max-width: 760px) {
  .user-shell { width: min(100% - 20px, 640px); padding-top: 10px; }
  .simple-hero { padding: 28px 24px; align-items: center; }
  .mini-palette { grid-template-columns: repeat(2, 28px); }
  .mini-palette i { width: 28px; height: 28px; }
  .user-step { padding: 23px 20px; }
  .editor-layout { grid-template-columns: minmax(0, 1fr); }
  .live-preview-card { position: static; width: min(100%, 330px); max-width: 100%; margin-inline: auto; }
  .dither-card,
  .diagnostic-grid { grid-template-columns: 1fr; }
  .connection-action,
  .send-layout { align-items: stretch; flex-direction: column; }
  .connection-action .button-row,
  .send-layout .large-button { width: 100%; }
  .connection-action .button { flex: 1 1 auto; }
  .connection-action .button-row { flex-wrap: nowrap; }
}

@media (max-width: 460px) {
  .simple-hero h1 { font-size: 2.7rem; }
  .mini-palette { display: none; }
  .tool-row { align-items: stretch; flex-direction: column; }
  .diagnostics > summary small { display: none; }
}

/* Minimal system UI — v0.5 */
:root {
  --apple-blue: #0071e3;
  --apple-blue-hover: #0077ed;
  --apple-bg: #f5f5f7;
  --apple-surface: rgba(255, 255, 255, 0.82);
  --apple-fill: #f1f1f3;
  --apple-separator: rgba(60, 60, 67, 0.16);
  --apple-label: #1d1d1f;
  --apple-secondary: #6e6e73;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display", system-ui, sans-serif;
}

body {
  color: var(--apple-label);
  background: var(--apple-bg);
  background-image: none;
  -webkit-font-smoothing: antialiased;
}

.apple-shell {
  width: min(980px, calc(100% - 40px));
  padding: 0 0 36px;
}

.app-header {
  display: flex;
  height: 72px;
  align-items: center;
  padding: 0 4px;
}

.app-header h1 {
  margin: 0;
  font-size: 1.38rem;
  font-weight: 650;
  letter-spacing: -0.025em;
  line-height: 1;
}

.apple-content {
  display: grid;
  gap: 18px;
  margin: 0;
}

.apple-content .panel {
  border: 1px solid rgba(255, 255, 255, 0.7);
  border-radius: 24px;
  background: var(--apple-surface);
  box-shadow:
    0 1px 2px rgba(0, 0, 0, 0.03),
    0 10px 35px rgba(0, 0, 0, 0.055);
  backdrop-filter: blur(24px) saturate(1.25);
  -webkit-backdrop-filter: blur(24px) saturate(1.25);
}

.editor-surface {
  padding: 28px;
}

.surface-header {
  display: flex;
  gap: 18px;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}

.surface-header h2,
.diagnostic-content h2 {
  margin: 0;
  font-size: 1.18rem;
  font-weight: 650;
  letter-spacing: -0.02em;
}

.source-actions,
.device-buttons {
  display: flex;
  gap: 8px;
  align-items: center;
}

.button.apple-button {
  min-height: 36px;
  padding: 0.48rem 0.86rem;
  border: 0;
  border-radius: 999px;
  color: var(--apple-label);
  background: var(--apple-fill);
  font-size: 0.83rem;
  font-weight: 560;
  box-shadow: none;
  transition: background 120ms ease, opacity 120ms ease, transform 120ms ease;
}

.button.apple-button:not(:disabled):hover {
  transform: none;
  background: #e8e8ed;
  box-shadow: none;
}

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

.button.apple-button.primary:not(:disabled):hover {
  background: var(--apple-blue-hover);
}

.button.apple-button:disabled {
  opacity: 0.42;
}

.file-picker {
  position: relative;
  cursor: pointer;
}

.apple-editor-layout {
  grid-template-columns: minmax(260px, 340px) minmax(0, 1fr);
  gap: 30px;
}

.apple-content .live-preview-card {
  top: 20px;
}

.apple-content .canvas-shell {
  padding: 8px;
  border: 0;
  border-radius: 22px;
  background: #fff;
  box-shadow:
    0 0 0 1px rgba(0, 0, 0, 0.08),
    0 12px 32px rgba(0, 0, 0, 0.09);
}

.apple-content .canvas-shell canvas {
  border: 0;
  border-radius: 15px;
}

.apple-content .live-preview-card figcaption,
.source-image-details,
.paste-hint {
  color: var(--apple-secondary);
  font-size: 0.75rem;
}

.apple-editor-panel {
  align-content: start;
  gap: 14px;
}

.apple-editor-panel .source-image-details {
  margin: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.control-group,
.apple-editor-panel .dither-card {
  padding: 17px;
  border: 0;
  border-radius: 16px;
  background: var(--apple-fill);
}

.apple-editor-panel .dither-card {
  grid-template-columns: minmax(0, 1.1fr) minmax(150px, 0.9fr);
  gap: 18px;
}

.range-control > span,
.dither-card label > span {
  color: var(--apple-secondary);
  font-size: 0.78rem;
}

input[type="range"] {
  accent-color: var(--apple-blue);
}

.apple-editor-panel .dither-card select {
  min-height: 36px;
  padding: 0 0.65rem;
  border: 1px solid var(--apple-separator);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.86);
  font-size: 0.82rem;
}

.apple-editor-panel .compact-details {
  border-top-color: var(--apple-separator);
}

.apple-editor-panel .compact-details summary {
  color: var(--apple-blue);
  font-weight: 520;
}

.action-surface {
  padding: 22px 24px;
}

.device-action-row {
  display: flex;
  gap: 20px;
  align-items: center;
  justify-content: space-between;
}

.device-state {
  display: flex;
  gap: 10px;
  align-items: center;
}

.device-state i {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: #aeaeb2;
}

.device-state:has(.connection-summary.success) i {
  background: #30d158;
  box-shadow: 0 0 0 4px rgba(48, 209, 88, 0.11);
}

.device-state:has(.connection-summary.warning) i {
  background: #ff9f0a;
}

.device-state:has(.connection-summary.working) i {
  background: var(--apple-blue);
}

.apple-content .connection-summary {
  color: var(--apple-label);
  font-size: 0.9rem;
  font-weight: 560;
}

.main-action {
  min-width: 156px;
}

.subtle-button:disabled {
  display: none;
}

.action-surface .progress-stack {
  gap: 6px;
  margin-top: 18px;
}

.action-surface .progress-stack:has(progress[value="0"]) {
  display: none;
}

.action-surface .progress-stack progress {
  height: 5px;
  color: var(--apple-blue);
  background: #e5e5ea;
}

.action-surface .progress-stack progress::-webkit-progress-bar {
  background: #e5e5ea;
}

.action-surface .progress-stack progress::-webkit-progress-value,
.action-surface .progress-stack progress::-moz-progress-bar {
  background: var(--apple-blue);
}

.action-surface .transfer-result {
  margin: 10px 0 0;
  padding: 0;
  border: 0;
  color: var(--apple-secondary);
  background: transparent;
  font-size: 0.78rem;
}

.action-surface .transfer-result.success { color: #248a3d; }
.action-surface .transfer-result.warning { color: #9a6700; }
.action-surface .transfer-result.error { color: #d70015; }

.apple-content .diagnostics {
  border-radius: 18px;
  box-shadow: none;
  background: rgba(255, 255, 255, 0.56);
}

.apple-content .diagnostics > summary {
  padding: 17px 20px;
  color: var(--apple-secondary);
  font-size: 0.82rem;
  font-weight: 560;
}

.diagnostic-content {
  border-top-color: var(--apple-separator);
}

.apple-shell footer {
  justify-content: flex-end;
  padding: 18px 5px 0;
  color: #8e8e93;
  font-size: 0.7rem;
}

button:focus-visible,
input:focus-visible,
select:focus-visible,
summary:focus-visible {
  outline: 3px solid rgba(0, 113, 227, 0.28);
  outline-offset: 2px;
}

@media (max-width: 720px) {
  .apple-shell { width: min(100% - 20px, 620px); }
  .app-header { height: 60px; padding-inline: 6px; }
  .editor-surface { padding: 20px; }
  .surface-header { margin-bottom: 20px; }
  .apple-editor-layout { grid-template-columns: minmax(0, 1fr); gap: 24px; }
  .apple-content .live-preview-card { position: static; width: min(100%, 330px); margin-inline: auto; }
  .apple-editor-panel .dither-card { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 480px) {
  .surface-header { align-items: flex-start; flex-direction: column; }
  .source-actions { width: 100%; }
  .source-actions .button { flex: 1 1 0; }
  .device-action-row { align-items: stretch; flex-direction: column; }
  .device-buttons { width: 100%; }
  .device-buttons .main-action { flex: 1 1 auto; }
  .device-buttons .subtle-button:not(:disabled) { flex: 0 0 auto; }
}