:root {
  --bg: #f5f5f7;
  --surface: #ffffff;
  --surface-2: #fbfbfd;
  --ink: #1d1d1f;
  --ink-2: #6e6e73;
  --ink-3: #86868b;
  --line: #d2d2d7;
  --line-2: #e5e5ea;
  --primary: #0071e3;
  --primary-hover: #0077ed;
  --accent: #1d1d1f;
  --accent-hover: #000;
  --danger: #ff3b30;
  --safe-bottom: env(safe-area-inset-bottom, 0px);
  --radius-lg: 18px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --shadow-1: 0 1px 2px rgba(0,0,0,0.04), 0 1px 3px rgba(0,0,0,0.06);
  --shadow-2: 0 6px 24px rgba(0,0,0,0.06), 0 2px 6px rgba(0,0,0,0.04);
  --ease: cubic-bezier(0.25, 0.1, 0.25, 1);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Segoe UI", "Hiragino Sans", "Yu Gothic UI", sans-serif;
  background: var(--bg);
  color: var(--ink);
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  letter-spacing: -0.01em;
}

header {
  padding: 72px 24px 36px;
  text-align: center;
  background: transparent;
}
.eyebrow {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.32em;
  color: var(--ink-3);
  text-transform: uppercase;
  margin-bottom: 18px;
}
header h1 {
  margin: 0;
  font-size: 48px;
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.0;
  background: linear-gradient(180deg, #000 0%, #434346 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  color: transparent;
}
header h1 .hanko {
  position: relative;
  display: inline-block;
  padding: 0 0.04em;
  color: #c42e2e;
  -webkit-text-fill-color: #c42e2e;
}
header h1 .hanko::before {
  content: "";
  position: absolute;
  inset: 8% -6% 8% -6%;
  border: 2px solid #c42e2e;
  border-radius: 8px;
  transform: rotate(-2deg);
  pointer-events: none;
}
header .desc {
  margin: 14px 0 0;
  color: var(--ink-2);
  font-size: 16px;
  font-weight: 400;
  letter-spacing: 0.005em;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px 40px;
}

.panel {
  background: var(--surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-2);
  padding: 28px 28px 22px;
}

.grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px 24px;
}
.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
}
.field label {
  font-size: 11px;
  color: var(--ink-3);
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.field label span:not(#sizeLabel) { color: var(--ink-2); font-weight: 500; }

.field input[type="number"],
.field input[type="text"] {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  font-size: 16px;
  font-family: inherit;
  background: var(--surface);
  color: var(--ink);
  transition: border-color 0.15s var(--ease), box-shadow 0.15s var(--ease);
  -webkit-appearance: none;
  appearance: none;
}
.field input[type="number"]:focus,
.field input[type="text"]:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(0,113,227,0.15);
}

.file-input {
  position: relative;
  border: 1px dashed var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  padding: 14px 14px;
  transition: all 0.15s var(--ease);
  cursor: pointer;
  min-height: 48px;
  display: flex;
  align-items: center;
}
.file-input:hover { border-color: var(--primary); background: #f5f8ff; }
.file-input input[type="file"] {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}
.file-placeholder {
  font-size: 14px;
  color: var(--ink-2);
  pointer-events: none;
}
.file-input.has-file .file-placeholder { color: var(--ink); font-weight: 500; }

.field input[type="range"] {
  width: 100%;
  height: 28px;
  -webkit-appearance: none;
  appearance: none;
  background: transparent;
}
.field input[type="range"]::-webkit-slider-runnable-track {
  height: 4px;
  background: var(--line-2);
  border-radius: 2px;
}
.field input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: #fff;
  border: 0.5px solid var(--line);
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
  margin-top: -9px;
  cursor: grab;
}
.field input[type="range"]::-moz-range-track {
  height: 4px;
  background: var(--line-2);
  border-radius: 2px;
}
.field input[type="range"]::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: #fff;
  border: 0.5px solid var(--line);
  box-shadow: 0 2px 6px rgba(0,0,0,0.15);
  cursor: grab;
}

.segmented {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
  padding: 2px;
  background: var(--line-2);
  border-radius: var(--radius-sm);
  min-height: 48px;
  position: relative;
}
.segmented input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
  width: 0;
  height: 0;
}
.segmented label {
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  border-radius: 6px;
  font-size: 14px;
  font-weight: 500;
  color: var(--ink-2);
  transition: background 0.2s var(--ease), color 0.2s var(--ease), box-shadow 0.2s var(--ease);
  user-select: none;
  -webkit-user-select: none;
  text-transform: none;
  letter-spacing: normal;
}
.segmented input:checked + label {
  background: var(--surface);
  color: var(--ink);
  box-shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 1px rgba(0,0,0,0.04);
  font-weight: 600;
}

body.mode-stamp .field-text { display: none; }
body.mode-text .field-stamp { display: none; }

.actions {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  margin-top: 22px;
}
button {
  padding: 14px 18px;
  border: 0;
  border-radius: 980px;
  font-weight: 600;
  cursor: pointer;
  font-size: 15px;
  font-family: inherit;
  letter-spacing: -0.01em;
  min-height: 48px;
  touch-action: manipulation;
  transition: all 0.15s var(--ease);
  -webkit-appearance: none;
  appearance: none;
}
button:disabled { opacity: 0.4; cursor: not-allowed; }
button:active:not(:disabled) { transform: scale(0.98); }
.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 1px 2px rgba(0,0,0,0.08);
}
.btn-primary:not(:disabled):hover { background: var(--primary-hover); }
.btn-accent {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 1px 2px rgba(0,0,0,0.12);
}
.btn-accent:not(:disabled):hover { background: var(--accent-hover); }
.btn-ghost {
  background: transparent;
  color: var(--ink);
  box-shadow: inset 0 0 0 1px var(--line);
}
.btn-ghost:not(:disabled):hover { background: var(--line-2); }

.hint, .status {
  margin: 0;
  font-size: 13px;
  letter-spacing: -0.005em;
}
.hint { color: var(--ink-3); margin-top: 10px; }
.status { color: var(--primary); min-height: 18px; margin-top: 14px; font-weight: 500; }
.status.error { color: var(--danger); }
.status.ok { color: #0a8744; }

.viewer {
  padding: 40px 0 calc(40px + var(--safe-bottom));
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
}
.page-label {
  align-self: flex-start;
  font-size: 11px;
  color: var(--ink-3);
  margin-bottom: -12px;
  padding-left: 4px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
}
.page-wrap {
  position: relative;
  background: #fff;
  box-shadow: var(--shadow-2);
  border-radius: var(--radius-md);
  overflow: hidden;
  line-height: 0;
  max-width: 100%;
}
.page-wrap canvas {
  display: block;
  max-width: 100%;
  height: auto;
  touch-action: manipulation;
  user-select: none;
  -webkit-user-select: none;
}
.page-wrap .overlay {
  position: absolute;
  inset: 0;
  cursor: crosshair;
  touch-action: none;
  -webkit-tap-highlight-color: transparent;
}
.stamp-preview {
  position: absolute;
  transform: translate(-50%, -50%);
  pointer-events: auto;
  border: 1.5px dashed rgba(255,59,48,0.85);
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center;
  touch-action: none;
  cursor: grab;
  border-radius: 4px;
}
.stamp-preview.dragging { cursor: grabbing; opacity: 0.8 !important; }
.text-preview {
  position: absolute;
  transform: translate(-50%, -50%);
  pointer-events: auto;
  border: 1.5px dashed rgba(0,113,227,0.85);
  padding: 2px 8px;
  white-space: nowrap;
  background: rgba(255,255,255,0.5);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  touch-action: none;
  cursor: grab;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Hiragino Sans", "Yu Gothic UI", sans-serif;
  font-weight: 600;
  line-height: 1.1;
  user-select: none;
  -webkit-user-select: none;
  border-radius: 4px;
  letter-spacing: -0.01em;
}
.text-preview.dragging { cursor: grabbing; opacity: 0.8 !important; }
.stamp-preview .remove,
.text-preview .remove {
  position: absolute;
  top: -12px;
  right: -12px;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--danger);
  color: #fff;
  font-size: 15px;
  line-height: 26px;
  text-align: center;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
  font-weight: 400;
}
.resize-handle {
  position: absolute;
  right: -10px;
  bottom: -10px;
  width: 20px;
  height: 20px;
  background: #fff;
  border: 2px solid var(--primary);
  border-radius: 50%;
  cursor: nwse-resize;
  touch-action: none;
  pointer-events: auto;
  box-shadow: 0 2px 6px rgba(0,0,0,0.2);
}

/* Tablet */
@media (min-width: 640px) {
  header { padding: 96px 24px 48px; }
  header h1 { font-size: 68px; }
  header .desc { font-size: 18px; margin-top: 18px; }
  .eyebrow { font-size: 12px; letter-spacing: 0.36em; margin-bottom: 22px; }
  main { padding: 0 28px 48px; }
  .panel { padding: 36px; }
  .grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px 28px;
  }
  .actions {
    grid-template-columns: auto auto auto;
    justify-content: flex-end;
    gap: 8px;
  }
  button { min-width: 140px; }
  .viewer { padding: 48px 0 calc(48px + var(--safe-bottom)); }
}

/* Desktop */
@media (min-width: 1024px) {
  header h1 { font-size: 80px; }
  .grid {
    grid-template-columns: 2fr 1.4fr 2fr 1fr;
  }
  .field-doc { grid-column: 1 / 2; }
  .field-mode { grid-column: 2 / 3; }
  .field-stamp { grid-column: 3 / 4; }
  body.mode-text .field-text { grid-column: 3 / 4; }
  .field-size { grid-column: 4 / 5; }
  .field-opacity { grid-column: 1 / -1; }
}