/* Cool Monochrome Design System */
:root {
  /* Primary Colors - Sharp Monochrome Palette */
  --primary-gradient: linear-gradient(135deg, #000000 0%, #1a1a1a 50%, #000000 100%);
  --secondary-gradient: linear-gradient(135deg, #111111 0%, #000000 100%);
  --accent-gradient: linear-gradient(135deg, #333333 0%, #000000 100%);

  /* Light Theme Colors - High Contrast */
  --bg-primary: #ffffff;
  --bg-secondary: #f9f9f9;
  --bg-gradient: radial-gradient(ellipse at top left, #fafafa 0%, #f0f0f0 50%, #e8e8e8 100%);
  --text-primary: #000000;
  --text-secondary: #1a1a1a;
  --text-muted: #7a7a7a;
  --link-color: #000000;
  --border-color: #d8d8d8;
  --shadow-sm: 0 2px 12px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.2);
  --shadow-xl: 0 16px 56px rgba(0, 0, 0, 0.25);

  /* Glassmorphism - Sharper */
  --glass-bg: rgba(255, 255, 255, 0.85);
  --glass-border: rgba(0, 0, 0, 0.12);

  /* Dark Theme Colors - Deep Black */
  --dark-bg-primary: #000000;
  --dark-bg-secondary: #0d0d0d;
  --dark-bg-gradient: radial-gradient(ellipse at top left, #1a1a1a 0%, #0d0d0d 50%, #000000 100%);
  --dark-text-primary: #ffffff;
  --dark-text-secondary: #e8e8e8;
  --dark-text-muted: #7a7a7a;
  --dark-border-color: #2a2a2a;
  --dark-glass-bg: rgba(13, 13, 13, 0.85);
  --dark-glass-border: rgba(255, 255, 255, 0.1);
}

* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans JP', 'Hiragino Sans', 'Hiragino Kaku Gothic ProN', 'Yu Gothic', 'Meiryo', sans-serif;
  background: var(--bg-gradient);
  background-attachment: fixed;
  color: var(--text-primary);
  line-height: 1.7;
  margin: 0;
  padding: 0;
  min-height: 100vh;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background 0.3s ease, color 0.3s ease;
}

body.dark-mode {
  background: var(--dark-bg-gradient);
  background-attachment: fixed;
  color: var(--dark-text-primary);
}

.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header styling - Cool Sharp Header */
.header {
  background: var(--glass-bg);
  backdrop-filter: blur(24px) saturate(180%);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  border-bottom: 2px solid var(--glass-border);
  box-shadow: none;
  position: sticky;
  top: 0;
  z-index: 100;
  width: 100%;
  transition: all 0.25s cubic-bezier(0.165, 0.84, 0.44, 1);
}

body.dark-mode .header {
  background: var(--dark-glass-bg);
  border-bottom: 2px solid var(--dark-glass-border);
}

.navbar {
  background: transparent !important;
  padding: 10px 0;
  width: 100%;
}

.navbar-brand {
  font-size: 14px;
  font-weight: 900;
  color: var(--text-primary);
  text-decoration: none;
  transition: all 0.25s cubic-bezier(0.165, 0.84, 0.44, 1);
  letter-spacing: 2px;
  text-transform: uppercase;
}

body.dark-mode .navbar-brand {
  color: var(--dark-text-primary);
}

.navbar-brand:hover {
  transform: translateX(4px);
  opacity: 0.7;
}

/* Card styling - Cool Sharp Cards */
.card {
  background: var(--glass-bg);
  backdrop-filter: blur(24px) saturate(180%);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  border: 1px solid var(--glass-border);
  border-radius: 4px;
  box-shadow: var(--shadow-md);
  transition: all 0.35s cubic-bezier(0.165, 0.84, 0.44, 1);
  margin-bottom: 20px;
  padding: 28px;
  position: relative;
  min-height: 150px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 2px;
  height: 100%;
  background: var(--primary-gradient);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.35s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.card::after {
  content: '';
  position: absolute;
  bottom: 0;
  right: 0;
  width: 100%;
  height: 2px;
  background: var(--primary-gradient);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.35s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.card:hover {
  box-shadow: var(--shadow-xl);
  transform: translateY(-4px);
  border-color: rgba(0, 0, 0, 0.25);
}

body.dark-mode .card:hover {
  border-color: rgba(255, 255, 255, 0.2);
}

.card:hover::before {
  transform: scaleY(1);
}

.card:hover::after {
  transform: scaleX(1);
}

body.dark-mode .card {
  background: var(--dark-glass-bg);
  border-color: var(--dark-glass-border);
}

.card-title {
  font-size: 19px;
  font-weight: 700;
  margin: 0 0 16px 0;
  color: var(--text-primary);
  line-height: 1.4;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  flex: 1;
  letter-spacing: -0.5px;
  transition: color 0.3s ease;
  text-transform: uppercase;
  font-size: 15px;
}

body.dark-mode .card-title {
  color: var(--dark-text-primary);
}

.card-link {
  color: var(--link-color);
  text-decoration: none;
  font-size: 11px;
  font-weight: 700;
  margin-right: 16px;
  padding: 8px 20px;
  border-radius: 0;
  background: transparent;
  border: 1px solid var(--border-color);
  transition: all 0.25s cubic-bezier(0.165, 0.84, 0.44, 1);
  display: inline-block;
  text-transform: uppercase;
  letter-spacing: 1.5px;
}

body.dark-mode .card-link {
  border-color: var(--dark-border-color);
  color: var(--dark-text-secondary);
}

.card-link:hover {
  background: var(--primary-gradient);
  color: white;
  border-color: transparent;
  transform: translateX(4px);
  text-decoration: none;
}

.text-muted {
  color: var(--text-muted) !important;
  font-size: 13px;
  font-weight: 500;
}

body.dark-mode .text-muted {
  color: var(--dark-text-muted) !important;
}

.card > div:last-child {
  margin-top: auto;
  padding-top: 8px;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

body.dark-mode .card > div:last-child {
  border-top: 1px solid var(--dark-border-color);
}

/* Grid layout improvements - Premium Responsive Grid */
.row {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
  margin: 32px 0;
  animation: fadeInUp 0.6s ease-out;
}

.col {
  display: contents;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Article content styling */
.article-content {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 24px;
  margin: 20px 0;
  box-shadow: var(--shadow-sm);
  line-height: 1.7;
  word-break: break-word;
  overflow-wrap: break-word;
}

body.dark-mode .article-content {
  background: var(--dark-bg-secondary);
  border-color: var(--dark-border-color);
}

.article-content h1,
.article-content h2,
.article-content h3,
.article-content h4,
.article-content h5,
.article-content h6 {
  margin: 24px 0 12px 0;
  font-weight: 700;
  color: var(--text-primary);
}

body.dark-mode .article-content h1,
body.dark-mode .article-content h2,
body.dark-mode .article-content h3,
body.dark-mode .article-content h4,
body.dark-mode .article-content h5,
body.dark-mode .article-content h6 {
  color: var(--dark-text-primary);
}

.article-content h2 {
  font-size: 20px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 6px;
}

body.dark-mode .article-content h2 {
  border-bottom-color: var(--dark-border-color);
}

.article-content p {
  margin: 12px 0;
  color: var(--text-primary);
}

body.dark-mode .article-content p {
  color: var(--dark-text-primary);
}

.article-content ul, .article-content ol {
  margin: 12px 0;
  padding-left: 20px;
  color: var(--text-primary);
}

body.dark-mode .article-content ul,
body.dark-mode .article-content ol {
  color: var(--dark-text-primary);
}

.article-content blockquote {
  border-left: 4px solid var(--border-color);
  margin: 16px 0;
  padding: 8px 16px;
  background: var(--bg-secondary);
  font-style: italic;
  color: var(--text-secondary);
}

body.dark-mode .article-content blockquote {
  border-left-color: var(--dark-border-color);
  background: var(--dark-bg-primary);
  color: var(--dark-text-secondary);
}

.article-content a {
  word-break: break-all;
  overflow-wrap: break-word;
  display: inline-block;
  max-width: 100%;
}

.article-content img {
  max-width: 100%;
  height: auto;
  display: block;
}

.article-content code {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 3px;
  padding: 2px 6px;
  font-family: 'SF Mono', Monaco, 'Roboto Mono', Consolas, monospace;
  font-size: 0.9em;
  color: var(--text-primary);
  word-break: break-all;
  overflow-wrap: break-word;
}

body.dark-mode .article-content code {
  background: var(--dark-bg-primary);
  border-color: var(--dark-border-color);
  color: var(--dark-text-primary);
}

.article-content pre {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 16px;
  overflow-x: auto;
  margin: 16px 0;
  word-break: break-word;
  white-space: pre-wrap;
  word-wrap: break-word;
}

body.dark-mode .article-content pre {
  background: var(--dark-bg-primary);
  border-color: var(--dark-border-color);
}

.article-content pre code {
  background: none;
  border: none;
  padding: 0;
  display: block;
  white-space: pre-wrap;
}

/* Page title styling - Cool Sharp Typography */
.display-3 {
  font-size: 48px;
  font-weight: 900;
  margin: 56px 0 40px 0;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -2px;
  line-height: 1.1;
  animation: fadeInUp 0.5s cubic-bezier(0.165, 0.84, 0.44, 1);
  text-transform: uppercase;
  position: relative;
}

.display-3::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 0;
  width: 60px;
  height: 3px;
  background: var(--primary-gradient);
  animation: slideIn 0.6s cubic-bezier(0.165, 0.84, 0.44, 1) 0.2s both;
}

@keyframes slideIn {
  from {
    width: 0;
  }
  to {
    width: 60px;
  }
}

body.dark-mode .display-3 {
  background: linear-gradient(135deg, #ffffff 0%, #cccccc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Footer styling - Premium Footer */
.footer {
  background: var(--glass-bg) !important;
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-top: 1px solid var(--glass-border);
  margin-top: 80px;
  padding: 32px 0;
}

body.dark-mode .footer {
  background: var(--dark-glass-bg) !important;
  border-top: 1px solid var(--dark-glass-border);
}

.footer span {
  color: var(--text-secondary) !important;
  font-size: 14px;
  font-weight: 500;
}

body.dark-mode .footer span {
  color: var(--dark-text-secondary) !important;
}

/* Section styling */
section {
  background: transparent !important;
  padding: 20px 0;
}

/* Empty state styling */
section > p:last-child {
  text-align: center;
  color: var(--text-muted);
  font-style: italic;
  margin: 40px 0;
}

body.dark-mode section > p:last-child {
  color: var(--dark-text-muted);
}

/* Responsive design - Premium Mobile Experience */
@media (max-width: 1024px) {
  .row {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
  }

  .display-3 {
    font-size: 36px;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }

  .row {
    grid-template-columns: 1fr;
    gap: 16px;
    margin: 24px 0;
  }

  .card {
    padding: 20px;
    min-height: 130px;
  }

  .card-link {
    padding: 5px 12px;
    font-size: 13px;
  }

  .article-content {
    padding: 20px;
    border-radius: 12px;
  }

  .display-3 {
    font-size: 32px;
    margin: 32px 0 24px 0;
    letter-spacing: -1px;
  }

  .navbar {
    padding: 16px 0;
  }

  .navbar-brand {
    font-size: 18px;
  }

  .footer {
    margin-top: 60px;
    padding: 24px 0;
  }
}

@media (max-width: 480px) {
  .display-3 {
    font-size: 28px;
  }

  .card-title {
    font-size: 16px;
  }

  .row {
    gap: 12px;
  }

  .card {
    padding: 16px;
  }

  .article-content {
    padding: 16px;
  }

  .article-content a {
    display: inline;
    word-break: break-all;
  }

  .article-content pre {
    padding: 12px;
    font-size: 0.85em;
    overflow-x: auto;
  }

  .article-content code {
    font-size: 0.8em;
    word-break: break-all;
  }
}

/* Animation for smooth transitions */
* {
  transition: color 0.2s ease, background-color 0.2s ease;
}

/* Link styling throughout the app */
a {
  color: var(--link-color);
  text-decoration: none;
  transition: color 0.3s ease;
}

a:hover {
  text-decoration: underline;
}

body.dark-mode a {
  color: #d4d4d4;
}

/* Action buttons styling */
.action-buttons {
  margin: 20px 0 30px 0;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* Button styling - Cool Sharp Buttons */
.btn {
  border-radius: 0;
  font-weight: 700;
  padding: 12px 32px;
  border: 2px solid var(--border-color);
  background: transparent;
  color: var(--text-primary);
  text-decoration: none;
  transition: all 0.25s cubic-bezier(0.165, 0.84, 0.44, 1);
  display: inline-block;
  font-size: 11px;
  cursor: pointer;
  box-shadow: none;
  text-transform: uppercase;
  letter-spacing: 1.5px;
}

.btn:hover {
  background: var(--primary-gradient);
  color: white;
  transform: translateX(4px);
  box-shadow: var(--shadow-md);
  text-decoration: none;
  border-color: transparent;
}

body.dark-mode .btn {
  background: transparent;
  color: var(--dark-text-primary);
  border-color: var(--dark-border-color);
}

body.dark-mode .btn:hover {
  background: var(--primary-gradient);
  color: white;
  border-color: transparent;
}

.btn-danger {
  background: transparent;
  color: var(--text-primary);
  border-color: var(--text-primary);
}

.btn-danger:hover {
  background: var(--secondary-gradient);
  color: white;
  transform: translateX(4px);
  box-shadow: var(--shadow-md);
  border-color: transparent;
}

body.dark-mode .btn-danger {
  color: var(--dark-text-primary);
  border-color: var(--dark-text-primary);
}

/* Dark Mode Toggle Button */
.dark-mode-toggle {
  background: transparent;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  border: 2px solid var(--border-color);
  border-radius: 0;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.165, 0.84, 0.44, 1);
  position: relative;
  overflow: hidden;
}

.dark-mode-toggle:hover {
  transform: translateX(4px);
  box-shadow: none;
  border-color: var(--text-primary);
}

body.dark-mode .dark-mode-toggle {
  border-color: var(--dark-border-color);
}

body.dark-mode .dark-mode-toggle:hover {
  border-color: var(--dark-text-primary);
}

.dark-mode-toggle svg {
  position: absolute;
  transition: all 0.25s cubic-bezier(0.165, 0.84, 0.44, 1);
  color: var(--text-primary);
}

.dark-mode-toggle .sun-icon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.dark-mode-toggle .moon-icon {
  opacity: 0;
  transform: rotate(180deg) scale(0);
}

body.dark-mode .dark-mode-toggle svg {
  color: var(--dark-text-primary);
}

body.dark-mode .dark-mode-toggle .sun-icon {
  opacity: 0;
  transform: rotate(-180deg) scale(0);
}

body.dark-mode .dark-mode-toggle .moon-icon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}