/* ============================================================
   カラーコード変換ツール — style.css
   Design System: purple accent (#7c3aed), off-white bg (#f9f7f4)
   ============================================================ */

:root {
  --primary: #7c3aed;
  --primary-hover: #6d28d9;
  --primary-rgb: 124, 58, 237;
  --primary-light: #ede9fe;
  --bg: #f9f7f4;
  --surface: #ffffff;
  --text: #1a1a2e;
  --text-muted: #6b7280;
  --text-weak: #9ca3af;
  --border: #e2e8f0;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 4px 12px rgba(0,0,0,0.08);
  --shadow-hover: 0 4px 16px rgba(0,0,0,0.10), 0 1px 4px rgba(0,0,0,0.06);
  --transition: 0.15s ease;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
}

/* ============================================================
   Reset & Base
   ============================================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Outfit', 'BIZ UDPGothic', -apple-system, BlinkMacSystemFont, 'Hiragino Sans', sans-serif;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  overflow-x: hidden;
  -webkit-text-size-adjust: 100%;
}

/* ============================================================
   Typography
   ============================================================ */
h1, h2, h3 {
  line-height: 1.3;
  letter-spacing: 0.01em;
}

code {
  font-family: 'Courier New', Consolas, monospace;
  background: var(--primary-light);
  color: var(--primary);
  padding: 0.1em 0.4em;
  border-radius: 4px;
  font-size: 0.875em;
}

/* ============================================================
   Header
   ============================================================ */
header {
  background: linear-gradient(135deg, #7c3aed 0%, #6d28d9 60%, #5b21b6 100%);
  color: #fff;
  padding: var(--space-8) var(--space-5) var(--space-6);
  text-align: center;
}

.header-inner {
  max-width: 860px;
  margin: 0 auto;
}

header h1 {
  font-size: clamp(1.25rem, 4vw, 1.8rem);
  font-weight: 800;
  letter-spacing: -0.01em;
}

.subtitle {
  font-size: 0.9rem;
  opacity: 0.88;
  margin-top: var(--space-2);
  line-height: 1.6;
}

/* ============================================================
   Layout
   ============================================================ */
main {
  max-width: 860px;
  margin: 0 auto;
  padding: var(--space-5) var(--space-4);
}

.section-gap {
  margin-bottom: var(--space-6);
}

/* ============================================================
   Privacy Notice
   ============================================================ */
.privacy-notice {
  background: linear-gradient(135deg, #f5f3ff, #ede9fe);
  border: 1px solid #c4b5fd;
  border-radius: var(--radius-sm);
  padding: var(--space-3) var(--space-4);
  font-size: 0.8125rem;
  color: #5b21b6;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.privacy-notice .bi {
  font-size: 1rem;
  flex-shrink: 0;
}

/* ============================================================
   Ad Unit
   ============================================================ */
.ad-unit {
  min-height: 0;
  background: linear-gradient(135deg, #f8f5ff, #f0ebff);
  border: 1px dashed #c4b5fd;
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-6);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-weak);
  font-size: 0.75rem;
}

/* ============================================================
   Card
   ============================================================ */
.card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: var(--space-6) var(--space-5);
  box-shadow: var(--shadow);
  border: 1px solid rgba(0,0,0,0.04);
}

/* ============================================================
   Section Title
   ============================================================ */
.section-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: var(--space-4);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.section-title .bi {
  color: var(--primary);
  font-size: 1.1rem;
}

.section-desc {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-top: -0.75rem;
  margin-bottom: var(--space-4);
}

/* ============================================================
   Section 1: Color Input
   ============================================================ */
.color-input-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

/* Color Preview */
.color-preview-area {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
}

.color-preview-box {
  width: 100%;
  height: 120px;
  border-radius: var(--radius);
  border: 1px solid rgba(0,0,0,0.08);
  box-shadow: var(--shadow);
  transition: background 0.2s ease;
}

.picker-label {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--primary);
  cursor: pointer;
  padding: var(--space-2) var(--space-4);
  border: 1.5px solid var(--primary);
  border-radius: var(--radius-sm);
  min-height: 44px;
  transition: background var(--transition), color var(--transition);
  user-select: none;
}

.picker-label:hover {
  background: var(--primary-light);
}

input[type="color"] {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
  pointer-events: none;
}

/* Color Fields */
.color-fields {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

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

.field-label {
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.input-copy-row {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.input-copy-row input {
  flex: 1;
}

/* RGB / HSL inputs */
.rgb-inputs {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.rgb-field {
  flex: 1;
  display: flex;
  align-items: center;
  gap: var(--space-1);
  min-width: 0;
}

.rgb-label {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  min-width: 14px;
  text-align: center;
}

/* Input base */
input[type="text"],
input[type="number"] {
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.625rem;
  font-size: 0.9375rem;
  font-family: inherit;
  background: #fff;
  color: var(--text);
  min-height: 44px;
  width: 100%;
  transition: border-color var(--transition), box-shadow var(--transition);
}

input[type="text"]:focus,
input[type="number"]:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.15);
}

.mono-input {
  font-family: 'Courier New', Consolas, monospace;
  letter-spacing: 0.04em;
}

/* Number input: hide spinners on mobile to save space */
input[type="number"] {
  -moz-appearance: textfield;
  text-align: center;
}
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
}

/* Copy Button */
.copy-btn {
  flex-shrink: 0;
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid #c4b5fd;
  border-radius: var(--radius-sm);
  padding: 0 0.75rem;
  min-height: 44px;
  font-size: 1rem;
  cursor: pointer;
  transition: background var(--transition), color var(--transition), transform 0.12s ease;
  display: flex;
  align-items: center;
  justify-content: center;
}

.copy-btn:hover {
  background: var(--primary);
  color: #fff;
  transform: translateY(-1px);
}

.copy-btn:active {
  transform: translateY(0) scale(0.97);
}

.copy-btn.copied {
  background: #059669;
  color: #fff;
  border-color: #059669;
}

/* ============================================================
   Section 2: Contrast Checker
   ============================================================ */
.contrast-inputs {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.contrast-color-pair {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

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

.contrast-color-row {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.contrast-color-row input[type="color"] {
  position: static;
  opacity: 1;
  width: 44px;
  height: 44px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  padding: 2px;
  background: #fff;
  flex-shrink: 0;
}

.contrast-color-row input[type="color"]:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.15);
}

.contrast-preview {
  border-radius: var(--radius-sm);
  padding: var(--space-4) var(--space-5);
  min-height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #7c3aed;
  transition: background var(--transition);
  border: 1px solid rgba(0,0,0,0.08);
}

.preview-text {
  font-size: 1.1rem;
  font-weight: 600;
  color: #ffffff;
  text-align: center;
  transition: color var(--transition);
}

/* Contrast Result */
.contrast-result-area {
  margin-top: var(--space-5);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
}

.contrast-ratio-display {
  display: flex;
  align-items: baseline;
  gap: 0.25rem;
}

.ratio-value {
  font-size: clamp(2.5rem, 8vw, 4rem);
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
  font-family: 'Outfit', sans-serif;
}

.ratio-colon {
  font-size: clamp(1.2rem, 4vw, 2rem);
  font-weight: 700;
  color: var(--text-muted);
}

.wcag-badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  justify-content: center;
}

.wcag-badge {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-3);
  border-radius: 100px;
  font-size: 0.8125rem;
  font-weight: 700;
  min-height: 36px;
}

.wcag-badge.pass {
  background: #dcfce7;
  color: #166534;
  border: 1px solid #86efac;
}

.wcag-badge.fail {
  background: #fee2e2;
  color: #991b1b;
  border: 1px solid #fca5a5;
}

.wcag-badge .bi {
  font-size: 0.9rem;
}

/* ============================================================
   Section 3: Palette
   ============================================================ */
.palette-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: var(--space-3);
}

.palette-swatch {
  border-radius: var(--radius-sm);
  overflow: hidden;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  box-shadow: var(--shadow);
}

.palette-swatch:hover {
  transform: translateY(-3px) scale(1.03);
  box-shadow: var(--shadow-hover);
}

.palette-swatch:active {
  transform: translateY(0) scale(0.98);
}

.swatch-color {
  height: 72px;
  width: 100%;
  transition: background var(--transition);
}

.swatch-info {
  background: var(--surface);
  padding: var(--space-2) var(--space-2);
  text-align: center;
}

.swatch-label {
  font-size: 0.6875rem;
  font-weight: 700;
  color: var(--text-muted);
  display: block;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.swatch-hex {
  font-size: 0.75rem;
  font-family: 'Courier New', monospace;
  color: var(--text);
  display: block;
  margin-top: 1px;
}

.swatch-copied {
  font-size: 0.6875rem;
  color: #059669;
  font-weight: 700;
  display: none;
}

/* ============================================================
   Section 4: CSS Output
   ============================================================ */
.css-output-area {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.css-code {
  background: #1e1b4b;
  color: #c4b5fd;
  border-radius: var(--radius-sm);
  padding: var(--space-4) var(--space-5);
  font-family: 'Courier New', Consolas, monospace;
  font-size: 0.8125rem;
  line-height: 1.8;
  overflow-x: auto;
  white-space: pre;
  border: 1px solid #312e81;
}

/* ============================================================
   Buttons
   ============================================================ */
.btn-primary {
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.625rem 1.5rem;
  font-size: 0.9rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  transition: background var(--transition), transform 0.12s ease, box-shadow var(--transition);
  box-shadow: 0 2px 8px rgba(var(--primary-rgb), 0.3);
  align-self: flex-start;
}

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(var(--primary-rgb), 0.35);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: none;
}

.btn-primary.copied {
  background: #059669;
  box-shadow: 0 2px 8px rgba(5, 150, 105, 0.3);
}

/* ============================================================
   How-to Section (details/summary)
   ============================================================ */
.howto-summary {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-height: 44px;
  user-select: none;
}

.howto-summary::-webkit-details-marker {
  display: none;
}

.howto-summary::after {
  content: '\F282';
  font-family: 'bootstrap-icons';
  margin-left: auto;
  font-size: 1.1rem;
  transition: transform 0.2s ease;
}

details[open] .howto-summary::after {
  transform: rotate(180deg);
}

.howto-content {
  margin-top: var(--space-4);
}

.howto-steps {
  padding-left: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.howto-steps li {
  font-size: 0.9rem;
  color: var(--text);
  line-height: 1.7;
}

/* ============================================================
   About Content
   ============================================================ */
.about-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.about-content p {
  font-size: 0.9rem;
  color: #374151;
  line-height: 1.8;
}

/* ============================================================
   FAQ
   ============================================================ */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: border-color var(--transition);
}

.faq-item[open] {
  border-color: #c4b5fd;
}

.faq-q {
  padding: var(--space-3) var(--space-4);
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  min-height: 48px;
  user-select: none;
  transition: background var(--transition);
}

.faq-q:hover {
  background: var(--primary-light);
}

.faq-q::-webkit-details-marker {
  display: none;
}

.faq-q::before {
  content: 'Q.';
  color: var(--primary);
  font-weight: 800;
  margin-right: var(--space-2);
  flex-shrink: 0;
}

.faq-q::after {
  content: '\F282';
  font-family: 'bootstrap-icons';
  margin-left: auto;
  font-size: 1rem;
  color: var(--text-muted);
  transition: transform 0.2s ease;
  flex-shrink: 0;
}

details[open] .faq-q::after {
  transform: rotate(180deg);
}

.faq-a {
  padding: var(--space-3) var(--space-4) var(--space-4);
  font-size: 0.875rem;
  color: #374151;
  line-height: 1.75;
  background: #faf9ff;
  border-top: 1px solid var(--border);
}

/* ============================================================
   Disclaimer
   ============================================================ */
.disclaimer-section p {
  font-size: 0.8125rem;
  color: var(--text-muted);
  line-height: 1.75;
}

/* ============================================================
   Footer
   ============================================================ */
footer {
  text-align: center;
  padding: var(--space-10) var(--space-4) var(--space-8);
  font-size: 0.85rem;
  color: var(--text-muted);
}

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

footer a {
  color: var(--primary);
  text-decoration: none;
}

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

/* ============================================================
   Responsive — Tablet (640px+)
   ============================================================ */
@media (min-width: 640px) {
  main {
    padding: var(--space-6) var(--space-6);
  }

  .card {
    padding: var(--space-8) var(--space-6);
  }

  .color-input-grid {
    flex-direction: row;
    align-items: flex-start;
  }

  .color-preview-area {
    flex-shrink: 0;
    width: 180px;
  }

  .color-preview-box {
    height: 160px;
  }

  .contrast-color-pair {
    flex-direction: row;
    gap: var(--space-5);
  }

  .contrast-field {
    flex: 1;
  }

  .css-output-area {
    flex-direction: row;
    align-items: flex-end;
  }

  .css-code {
    flex: 1;
  }

  .palette-grid {
    grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
  }
}

/* ============================================================
   Responsive — Desktop (900px+)
   ============================================================ */
@media (min-width: 900px) {
  main {
    padding: var(--space-8) var(--space-4);
  }

  header h1 {
    font-size: 1.8rem;
  }

  .color-preview-box {
    height: 180px;
  }
}