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

body {
  font-family: "Noto Sans JP", -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: #333;
  background: #f0f4f8;
}

/* ===== Header ===== */
header {
  background: linear-gradient(135deg, #1a2a4a 0%, #2c4a7c 100%);
  color: white;
  padding: 1.5rem 1rem;
  text-align: center;
}

header h1 {
  font-size: 1.1rem;
  line-height: 1.4;
  font-weight: 700;
}

.subtitle {
  font-size: 0.875rem;
  opacity: 0.85;
  margin-top: 0.4rem;
}

/* ===== Main ===== */
main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem;
}

/* ===== Ad unit ===== */
.ad-unit {
  margin: 1.25rem 0;
}

/* ===== Editor layout ===== */
.editor-layout {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

/* ===== Settings panel ===== */
.settings-panel {
  background: white;
  border-radius: 12px;
  padding: 1.25rem 1rem;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.setting-group {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.setting-group.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.setting-label {
  font-size: 0.875rem;
  font-weight: 700;
  color: #374151;
}

/* ===== Preset buttons ===== */
.preset-buttons {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.preset-btn {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  font-weight: 600;
  border: 1.5px solid #d1d5db;
  border-radius: 20px;
  background: #f9fafb;
  color: #6b7280;
  cursor: pointer;
  transition: all 0.2s;
  min-height: 44px;
  font-family: inherit;
}

.preset-btn:hover {
  border-color: #2c4a7c;
  color: #2c4a7c;
  background: #eff6ff;
}

.preset-btn.active {
  background: #1a2a4a;
  border-color: #1a2a4a;
  color: white;
}

/* ===== Form group ===== */
.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.form-group label,
.form-group .setting-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: #374151;
}

.char-limit {
  font-weight: 400;
  color: #9ca3af;
  font-size: 0.8rem;
}

.form-group input[type="text"],
.form-group textarea {
  width: 100%;
  padding: 0.65rem 0.75rem;
  font-size: 1rem;
  border: 1.5px solid #d1d5db;
  border-radius: 8px;
  background: #f9fafb;
  color: #111827;
  transition: border-color 0.2s;
  min-height: 44px;
  font-family: inherit;
  resize: vertical;
}

.form-group textarea {
  min-height: 60px;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: #2c4a7c;
  background: white;
}

.char-counter {
  font-size: 0.75rem;
  color: #9ca3af;
  text-align: right;
}

.char-counter.warn {
  color: #d97706;
}

.char-counter.over {
  color: #dc2626;
}

/* ===== Color palette ===== */
.color-palette {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  align-items: center;
}

.color-swatch {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s;
  position: relative;
  min-width: 44px;
}

.color-swatch:hover {
  transform: scale(1.15);
  box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}

.color-swatch.active {
  border-color: #2c4a7c;
  box-shadow: 0 0 0 3px rgba(44, 74, 124, 0.3);
}

.color-custom-label {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1.5px dashed #9ca3af;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #f9fafb;
  transition: border-color 0.2s;
  overflow: hidden;
  position: relative;
}

.color-custom-label:hover {
  border-color: #2c4a7c;
}

.color-custom-icon {
  font-size: 1rem;
  color: #6b7280;
  pointer-events: none;
}

.color-custom-label input[type="color"] {
  position: absolute;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
  border: none;
  padding: 0;
}

/* ===== Radio group ===== */
.radio-group {
  display: flex;
  gap: 1rem;
}

.radio-label {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.875rem;
  color: #374151;
  cursor: pointer;
  min-height: 44px;
}

.radio-label input[type="radio"] {
  accent-color: #2c4a7c;
  width: 16px;
  height: 16px;
}

/* ===== Download button ===== */
.download-btn {
  width: 100%;
  padding: 0.875rem 1.5rem;
  font-size: 1rem;
  font-weight: 700;
  background: linear-gradient(135deg, #1a2a4a 0%, #2c4a7c 100%);
  color: white;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.1s;
  min-height: 52px;
  font-family: inherit;
  letter-spacing: 0.02em;
  box-shadow: 0 4px 12px rgba(44, 74, 124, 0.3);
}

.download-btn:hover {
  opacity: 0.92;
}

.download-btn:active {
  transform: scale(0.98);
}

/* ===== Preview panel ===== */
.preview-panel {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.preview-label {
  font-size: 0.875rem;
  font-weight: 700;
  color: #374151;
}

.preview-note {
  font-size: 0.75rem;
  font-weight: 400;
  color: #9ca3af;
}

.preview-wrapper {
  width: 100%;
  background: #e2e8f0;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  /* maintain 1200:630 aspect ratio */
  aspect-ratio: 1200 / 630;
  position: relative;
}

.preview-wrapper canvas {
  width: 100%;
  height: 100%;
  display: block;
}

/* ===== How-to section ===== */
.howto-section {
  margin-top: 1.5rem;
  background: white;
  border-radius: 12px;
  padding: 1.5rem 1rem;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.howto-section h2 {
  font-size: 1.05rem;
  color: #1a2a4a;
  margin-bottom: 0.75rem;
  margin-top: 1.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid #e2e8f0;
}

.howto-section h2:first-child {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}

.howto-section ol {
  padding-left: 1.25rem;
  color: #4b5563;
  font-size: 0.9rem;
}

.howto-section ol li {
  margin-bottom: 0.5rem;
  line-height: 1.6;
}

.howto-section p {
  font-size: 0.9rem;
  color: #4b5563;
  line-height: 1.8;
  margin-bottom: 0.75rem;
}

.howto-section p:last-of-type {
  margin-bottom: 0;
}

/* ===== Affiliate block ===== */
.affiliate-block {
  margin-top: 1.5rem;
  padding: 1rem;
  background: #fafafa;
  border: 1px solid #e5e7eb;
  border-radius: 8px;
}

.affiliate-label {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  color: #9ca3af;
  border: 1px solid #d1d5db;
  padding: 0 0.35rem;
  border-radius: 3px;
  margin-bottom: 0.5rem;
}

.affiliate-desc {
  font-size: 0.85rem;
  color: #4b5563;
  margin-bottom: 0.6rem;
}

.affiliate-link {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 600;
  color: #2c4a7c;
  text-decoration: underline;
  min-height: 44px;
  line-height: 44px;
}

/* ===== Footer ===== */
footer {
  text-align: center;
  padding: 2rem 1rem;
  font-size: 0.85rem;
  color: #9ca3af;
}

footer p {
  margin-bottom: 0.4rem;
}

footer a {
  color: #6b7280;
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

/* ===== Responsive: tablet+ ===== */
@media (min-width: 640px) {
  header {
    padding: 2rem 1.5rem;
  }

  header h1 {
    font-size: 1.3rem;
  }

  .subtitle {
    font-size: 0.95rem;
  }

  main {
    padding: 1.5rem 2rem;
  }

  .settings-panel {
    padding: 1.5rem;
  }
}

@media (min-width: 900px) {
  .editor-layout {
    flex-direction: row;
    align-items: flex-start;
  }

  .settings-panel {
    width: 360px;
    flex-shrink: 0;
    position: sticky;
    top: 1rem;
  }

  .preview-panel {
    flex: 1;
  }
}