/* Mark It Down - Warm Minimalism Design System */
/* Japanese "Ma" (間) - Intentional breathing room */

/* ========================================
   1. DESIGN TOKENS & CSS VARIABLES
   ======================================== */

@import url('https://fonts.googleapis.com/css2?family=Lora:wght@400;500;600&family=Raleway:wght@300;400;500;600&display=swap');

:root {
  /* Warm Color Palette - Soft, warm off-white */
  --bg-primary: #FAFAF9;
  --bg-secondary: #F5F4F2;
  --bg-accent: #EFEDE9;
  --bg-card: #FFFFFF;

  /* Text Colors - Warm tones with good contrast */
  --text-primary: #2D2A26;
  --text-secondary: #5C5854;
  --text-muted: #8A8580;

  /* Accent - Refined warm earth tone */
  --accent-primary: #8B7355;
  --accent-hover: #6D5A44;
  --accent-light: rgba(139, 115, 85, 0.08);

  /* Borders - Softer, warmer */
  --border-primary: #E8E6E2;
  --border-subtle: #F2F0ED;
  --border-card: rgba(45, 42, 38, 0.06);

  /* Shadows - Layered for depth and warmth (using accent color) */
  --shadow-sm: 0 1px 2px rgba(139, 115, 85, 0.04);
  --shadow-md: 0 4px 16px rgba(139, 115, 85, 0.06), 0 2px 4px rgba(139, 115, 85, 0.04);
  --shadow-lg: 0 8px 32px rgba(139, 115, 85, 0.1), 0 4px 8px rgba(139, 115, 85, 0.05);
  --shadow-card: 0 2px 8px rgba(139, 115, 85, 0.05), 0 1px 2px rgba(139, 115, 85, 0.03);
  --shadow-screenshot: 0 16px 48px rgba(45, 42, 38, 0.12), 0 8px 16px rgba(139, 115, 85, 0.08);

  /* Typography */
  --font-serif: 'Lora', Georgia, serif;
  --font-sans: 'Raleway', -apple-system, BlinkMacSystemFont, sans-serif;

  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.75rem;
  --font-size-hero: 3.5rem;

  /* Spacing - Balanced for Ma (間) principle */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  --spacing-section: 6rem;
  --spacing-hero: 8rem;

  /* Line Height */
  --line-height-tight: 1.3;
  --line-height-normal: 1.7;
  --line-height-relaxed: 1.9;

  /* Letter Spacing */
  --letter-spacing-tight: -0.02em;
  --letter-spacing-normal: 0;
  --letter-spacing-wide: 0.02em;

  /* Border Radius - Subtle, warm curves */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* Transitions - Smooth ease-out for natural feel */
  --transition-fast: 150ms ease-out;
  --transition-base: 250ms ease-out;
  --transition-slow: 400ms ease-out;
}

/* ========================================
   2. BASE STYLES
   ======================================== */

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

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

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: var(--line-height-relaxed);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ========================================
   3. ACCESSIBILITY
   ======================================== */

.skip-to-content {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-primary);
  color: white;
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: 0 0 var(--radius-md) var(--radius-md);
  text-decoration: none;
  font-weight: 500;
  font-size: var(--font-size-sm);
  z-index: 1000;
  transition: top var(--transition-fast);
}

.skip-to-content:focus {
  top: 0;
  outline: none;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Focus States */
:focus {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ========================================
   4. LAYOUT
   ======================================== */

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: var(--spacing-lg);
}

/* ========================================
   5. HEADER
   ======================================== */

header {
  text-align: center;
  padding: var(--spacing-hero) 0 var(--spacing-2xl);
}

.header-logo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.logo-icon {
  width: 56px;
  height: 56px;
  object-fit: contain;
  opacity: 0.9;
}

header h1 {
  font-family: var(--font-serif);
  font-size: var(--font-size-3xl);
  font-weight: 500;
  color: var(--text-primary);
  letter-spacing: var(--letter-spacing-tight);
  margin: 0;
}

header .tagline {
  font-family: var(--font-sans);
  font-size: var(--font-size-lg);
  font-weight: 300;
  color: var(--text-secondary);
  margin-top: var(--spacing-sm);
  letter-spacing: var(--letter-spacing-wide);
}

/* ========================================
   6. MAIN CONTENT
   ======================================== */

main {
  padding: 0;
}

section {
  margin-bottom: var(--spacing-section);
}

/* ========================================
   7. TYPOGRAPHY
   ======================================== */

h2 {
  font-family: var(--font-serif);
  font-size: var(--font-size-2xl);
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: var(--spacing-lg);
  letter-spacing: var(--letter-spacing-tight);
  line-height: var(--line-height-tight);
}

h3 {
  font-family: var(--font-serif);
  font-size: var(--font-size-xl);
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
  letter-spacing: var(--letter-spacing-tight);
}

p {
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  color: var(--text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-md);
}

/* ========================================
   8. HERO SECTION
   ======================================== */

.hero {
  text-align: center;
  padding: var(--spacing-lg) 0 var(--spacing-xl);
}

.hero-tagline {
  font-family: var(--font-serif);
  font-size: clamp(2.5rem, 8vw, 4.5rem);
  font-weight: 400;
  color: var(--text-primary);
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-lg);
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-family: var(--font-sans);
  font-size: var(--font-size-lg);
  font-weight: 300;
  color: var(--text-secondary);
  max-width: 520px;
  margin: 0 auto var(--spacing-xl);
  line-height: var(--line-height-relaxed);
}

.hero-image {
  margin: var(--spacing-2xl) 0;
}

.hero-image img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-primary);
  box-shadow: var(--shadow-md);
}

/* ========================================
   9. PHILOSOPHY SECTION
   ======================================== */

.philosophy {
  padding: var(--spacing-2xl) 0;
  text-align: center;
}

.philosophy-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
  max-width: 500px;
  margin: 0 auto;
}

.philosophy-item {
  padding: 0;
}

.philosophy-item::before {
  display: none;
}

.philosophy-item h3 {
  font-family: var(--font-serif);
  font-size: var(--font-size-xl);
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
}

.philosophy-item p {
  font-size: var(--font-size-base);
  color: var(--text-secondary);
  margin: 0;
  line-height: var(--line-height-relaxed);
}

/* Flow Section (Information Flow Philosophy) */
.flow-section {
  padding: var(--spacing-2xl) 0;
  text-align: center;
  border-top: 1px solid var(--border-subtle);
}

.flow-section h2 {
  font-family: var(--font-serif);
  font-size: var(--font-size-2xl);
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
  letter-spacing: var(--letter-spacing-wide);
}

.flow-description {
  font-size: var(--font-size-lg);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
}

.flow-section .philosophy-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--spacing-md);
  max-width: 800px;
}

/* Flow item with icon */
.flow-item {
  position: relative;
  padding: var(--spacing-md);
  background: var(--bg-card);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.flow-item:hover {
  border-color: var(--border-primary);
  box-shadow: var(--shadow-card);
}

.flow-icon {
  width: 24px;
  height: 24px;
  margin: 0 auto var(--spacing-xs);
  color: var(--accent-primary);
}

.flow-icon svg {
  width: 100%;
  height: 100%;
}

/* Arrow between flow items */
.flow-arrow {
  display: none;
}

@media (min-width: 769px) {
  .flow-section .philosophy-list {
    position: relative;
  }

  .flow-arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: var(--font-size-lg);
  }
}

@media (max-width: 768px) {
  .flow-section .philosophy-list {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 480px) {
  .flow-section .philosophy-list {
    grid-template-columns: 1fr;
  }
}

/* ========================================
   10. BUTTONS
   ======================================== */

.buttons {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
  justify-content: center;
  margin-top: var(--spacing-xl);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-sm) var(--spacing-xl);
  min-height: 52px;
  border-radius: var(--radius-md);
  text-decoration: none;
  font-family: var(--font-sans);
  font-weight: 500;
  font-size: var(--font-size-base);
  cursor: pointer;
  border: none;
  transition: background var(--transition-base), box-shadow var(--transition-base), transform var(--transition-fast);
}

.btn-primary {
  background: var(--accent-primary);
  color: white;
  box-shadow: 0 2px 8px rgba(139, 115, 85, 0.2);
}

.btn-primary:hover {
  background: var(--accent-hover);
  box-shadow: 0 4px 16px rgba(139, 115, 85, 0.25);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: 0 1px 4px rgba(139, 115, 85, 0.2);
}

@media (prefers-reduced-motion: reduce) {
  .btn-primary:hover,
  .btn-primary:active {
    transform: none;
  }
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-secondary);
  border: 1px solid var(--border-primary);
}

.btn-secondary:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  background: var(--accent-light);
}

/* ========================================
   11. LINKS
   ======================================== */

a {
  color: var(--accent-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-hover);
}

/* ========================================
   12. SCREENSHOT SECTION
   ======================================== */

.screenshot-section {
  text-align: center;
  padding: var(--spacing-2xl) 0;
}

.screenshot-section img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-xl);
  border: 1px solid var(--border-primary);
  box-shadow: var(--shadow-screenshot);
  transition: box-shadow var(--transition-slow);
}

.screenshot-section img:hover {
  box-shadow: 0 20px 60px rgba(45, 42, 38, 0.15), 0 8px 20px rgba(139, 115, 85, 0.1);
}

@media (prefers-reduced-motion: reduce) {
  .screenshot-section img {
    transition: none;
  }
}

.screenshot-caption {
  font-size: var(--font-size-sm);
  color: var(--text-muted);
  margin-top: var(--spacing-lg);
  font-style: italic;
  letter-spacing: var(--letter-spacing-wide);
}

/* ========================================
   12.5 COMING SOON SECTION
   ======================================== */

.coming-soon-section {
  text-align: center;
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--border-subtle);
}

.coming-soon-section h2 {
  font-family: var(--font-serif);
  font-size: var(--font-size-xl);
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
}

.coming-soon-status {
  font-size: var(--font-size-sm);
  color: var(--accent-primary);
  font-weight: 500;
  margin-bottom: var(--spacing-lg);
  display: inline-block;
  padding: 2px 12px;
  background: var(--accent-light);
  border-radius: var(--radius-sm);
}

.coming-soon-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-md);
  max-width: 600px;
  margin: 0 auto;
  text-align: left;
}

.coming-soon-list li {
  padding: var(--spacing-sm);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast);
}

.coming-soon-list li:hover {
  border-color: var(--border-primary);
}

.coming-soon-list strong {
  display: block;
  font-family: var(--font-sans);
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.coming-soon-list span {
  font-size: var(--font-size-sm);
  color: var(--text-muted);
  line-height: 1.4;
}

@media (max-width: 640px) {
  .coming-soon-list {
    grid-template-columns: 1fr;
  }
}

/* ========================================
   13. TAB NAVIGATION (Features Page)
   ======================================== */

.tab-container {
  margin-bottom: var(--spacing-lg);
  scroll-margin-top: var(--spacing-sm);
}

/* Hide radio inputs */
.tab-container input[type="radio"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

/* Tab navigation bar - compact horizontal scroll on mobile */
.tab-nav {
  display: flex;
  flex-wrap: nowrap;
  gap: var(--spacing-xs);
  justify-content: center;
  margin-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: var(--spacing-xs);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.tab-nav::-webkit-scrollbar {
  display: none;
}

.tab-nav label {
  padding: var(--spacing-xs) var(--spacing-sm);
  font-family: var(--font-sans);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  border-bottom-width: 2px;
  transition: color var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
  flex-shrink: 0;
}

.tab-nav label:hover {
  color: var(--text-primary);
  background: var(--bg-secondary);
}

/* Active tab style - 8 tabs */
#tab-modes:checked ~ .tab-nav label[for="tab-modes"],
#tab-markdown:checked ~ .tab-nav label[for="tab-markdown"],
#tab-view:checked ~ .tab-nav label[for="tab-view"],
#tab-notes:checked ~ .tab-nav label[for="tab-notes"],
#tab-storage:checked ~ .tab-nav label[for="tab-storage"],
#tab-git:checked ~ .tab-nav label[for="tab-git"],
#tab-dual:checked ~ .tab-nav label[for="tab-dual"],
#tab-keys:checked ~ .tab-nav label[for="tab-keys"] {
  color: var(--accent-primary);
  background: var(--bg-card);
  border: 1px solid var(--border-primary);
  border-bottom-color: var(--accent-primary);
  border-bottom-width: 2px;
  box-shadow: var(--shadow-sm);
}

/* Tab panels - hidden by default */
.tab-panel {
  display: none;
}

/* Show active panel - 8 tabs */
#tab-modes:checked ~ .tab-content .tab-panel-modes,
#tab-markdown:checked ~ .tab-content .tab-panel-markdown,
#tab-view:checked ~ .tab-content .tab-panel-view,
#tab-notes:checked ~ .tab-content .tab-panel-notes,
#tab-storage:checked ~ .tab-content .tab-panel-storage,
#tab-git:checked ~ .tab-content .tab-panel-git,
#tab-dual:checked ~ .tab-content .tab-panel-dual,
#tab-keys:checked ~ .tab-content .tab-panel-keys {
  display: block;
}

/* Tab content area - compact height */
.tab-content {
  min-height: 280px;
}

/* Tab panel sections - compact */
.tab-panel section {
  margin-bottom: var(--spacing-md);
}

.tab-panel section:last-child {
  margin-bottom: 0;
}

/* Compact philosophy list in tabs */
.tab-panel .philosophy-list {
  gap: var(--spacing-sm);
}

.tab-panel .philosophy-item h3 {
  font-size: var(--font-size-base);
  margin-bottom: 0.25rem;
}

.tab-panel .philosophy-item p {
  font-size: var(--font-size-sm);
  margin: 0;
}

.tab-panel h2 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-sm);
}

.tab-panel > section > p {
  font-size: var(--font-size-sm);
  margin-bottom: var(--spacing-sm);
}

/* Keyboard shortcuts table */
.shortcuts-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
}

.shortcuts-table th,
.shortcuts-table td {
  padding: var(--spacing-xs) var(--spacing-sm);
  text-align: left;
  border-bottom: 1px solid var(--border-subtle);
}

.shortcuts-table th {
  font-family: var(--font-serif);
  font-weight: 500;
  color: var(--text-primary);
}

.shortcuts-table td {
  color: var(--text-secondary);
}

.shortcuts-table kbd {
  font-family: var(--font-sans);
  font-size: var(--font-size-sm);
  background: var(--bg-secondary);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-primary);
}

/* Tab panel animation */
.tab-panel {
  animation: fadeIn 0.2s ease-out;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  .tab-panel {
    animation: none;
  }
}

/* Responsive: Horizontal scroll with hint on mobile */
@media (max-width: 768px) {
  .tab-nav-wrapper {
    position: relative;
  }

  .tab-nav-wrapper::after {
    content: "";
    position: absolute;
    right: 0;
    top: 0;
    bottom: var(--spacing-xs);
    width: 48px;
    background: linear-gradient(to right, transparent, var(--bg-primary));
    pointer-events: none;
  }
}

@media (max-width: 640px) {
  .tab-nav {
    justify-content: flex-start;
    padding-left: var(--spacing-sm);
    padding-right: var(--spacing-sm);
  }

  .tab-nav label {
    padding: var(--spacing-xs) var(--spacing-xs);
    font-size: 0.8rem;
  }
}

/* ========================================
   14. CTA SECTION
   ======================================== */

.cta-section {
  text-align: center;
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--border-subtle);
}

.cta-section h2 {
  font-family: var(--font-serif);
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-sm);
}

.cta-section p {
  max-width: 440px;
  margin: 0 auto var(--spacing-md);
  font-size: var(--font-size-sm);
}

/* ========================================
   14. FOOTER
   ======================================== */

footer {
  text-align: center;
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--border-subtle);
  margin-top: var(--spacing-2xl);
}

footer p {
  font-size: var(--font-size-sm);
  color: var(--text-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

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

footer a:hover {
  color: var(--accent-primary);
  text-decoration: underline;
}

/* ========================================
   15. RESPONSIVE - TABLET
   ======================================== */

@media (max-width: 768px) {
  :root {
    --spacing-section: 4rem;
    --spacing-hero: 5rem;
  }

  .container {
    padding: var(--spacing-md);
  }

  header {
    padding: var(--spacing-xl) 0 var(--spacing-lg);
  }

  .hero-tagline {
    font-size: var(--font-size-4xl);
  }

  .hero-subtitle {
    font-size: var(--font-size-base);
  }

  .buttons {
    flex-direction: column;
    align-items: center;
  }

  .btn {
    width: 100%;
    max-width: 300px;
  }
}

/* ========================================
   16. RESPONSIVE - MOBILE
   ======================================== */

@media (max-width: 480px) {
  :root {
    --spacing-section: 3rem;
    --spacing-hero: 4rem;
  }

  .container {
    padding: var(--spacing-sm);
  }

  header h1 {
    font-size: var(--font-size-2xl);
  }

  .hero-tagline {
    font-size: var(--font-size-3xl);
  }

  h2 {
    font-size: var(--font-size-xl);
  }

  .philosophy-list {
    gap: var(--spacing-sm);
  }

  footer p {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
}

/* ========================================
   17. RESPONSIVE - LARGE SCREENS (1600px+)
   ======================================== */

@media (min-width: 1600px) {
  .container {
    max-width: 1000px;
  }

  .hero-tagline {
    font-size: 5rem;
  }

  .hero-subtitle {
    font-size: var(--font-size-xl);
    max-width: 600px;
  }

  header h1 {
    font-size: var(--font-size-4xl);
  }

  .philosophy-list {
    max-width: 600px;
  }

  .flow-section .philosophy-list {
    max-width: 1000px;
  }

  .screenshot-section img {
    max-width: 900px;
  }
}

/* ========================================
   18. PRINT STYLES
   ======================================== */

@media print {
  body {
    background: white;
    color: black;
  }

  .skip-to-content,
  .buttons {
    display: none;
  }

  a {
    color: black;
    text-decoration: underline;
  }
}