/* ==========================================================================
   c1t0d0s0 Portal - Design System & Stylesheet
   ========================================================================== */

/* --- CSS Variables & Theme Definition --- */
:root {
  /* Color Palette - Light Theme (Default) */
  --bg-base: #ffffff;
  --bg-surface: #f5f5f7;
  --bg-card: #ffffff;
  --bg-card-hover: #ffffff;
  --bg-header: rgba(255, 255, 255, 0.72);
  --bg-control: #f5f5f7;
  --bg-control-hover: #ebebed;

  --border-color: rgba(0, 0, 0, 0.08);
  --border-color-hover: rgba(0, 0, 0, 0.16);

  --text-primary: #1d1d1f;
  --text-secondary: #6e6e73;
  --text-muted: #86868b;

  --accent: #0071e3;
  --accent-hover: #0077ed;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.07);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.10);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;

  --font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Text', 'SF Pro JP',
                 'Hiragino Sans', 'Hiragino Kaku Gothic ProN', 'Noto Sans JP',
                 'Segoe UI', 'Yu Gothic UI', Meiryo, sans-serif;
  --transition-smooth: all 0.25s cubic-bezier(0.25, 0.1, 0.25, 1);
}

/* Dark Theme Overrides */
[data-theme="dark"] {
  --bg-base: #000000;
  --bg-surface: #1d1d1f;
  --bg-card: #1d1d1f;
  --bg-card-hover: #232325;
  --bg-header: rgba(0, 0, 0, 0.72);
  --bg-control: #1d1d1f;
  --bg-control-hover: #2c2c2e;

  --border-color: rgba(255, 255, 255, 0.12);
  --border-color-hover: rgba(255, 255, 255, 0.24);

  --text-primary: #f5f5f7;
  --text-secondary: #a1a1a6;
  --text-muted: #86868b;

  --accent: #2997ff;
  --accent-hover: #47a5ff;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.6);
}

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

html {
  font-family: var(--font-family);
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  line-height: 1.6;
  letter-spacing: -0.01em;
  overflow-x: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

a {
  color: inherit;
  text-decoration: none;
}

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

/* --- Header / Navigation --- */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-header);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border-color);
}

.header-container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0.85rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.0625rem;
  letter-spacing: -0.02em;
}

.logo-icon {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.05rem;
  line-height: 1;
}

.logo-text {
  font-weight: 600;
  color: var(--text-primary);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Language Toggle Button */
.lang-toggle-btn {
  background: var(--bg-control);
  border: none;
  color: var(--text-primary);
  height: 36px;
  padding: 0 0.9rem;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  gap: 0.4rem;
  cursor: pointer;
  font-family: inherit;
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0;
  transition: var(--transition-smooth);
}

.lang-toggle-btn:hover {
  background: var(--bg-control-hover);
}

.lang-toggle-btn svg {
  width: 16px;
  height: 16px;
  color: var(--text-secondary);
  flex-shrink: 0;
}

/* Theme Toggle Button */
.theme-toggle-btn {
  background: var(--bg-control);
  border: none;
  color: var(--text-primary);
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.theme-toggle-btn:hover {
  background: var(--bg-control-hover);
}

.theme-toggle-btn svg {
  width: 17px;
  height: 17px;
  stroke-width: 1.75;
  color: var(--text-secondary);
}

.theme-icon-moon {
  display: none;
}

[data-theme="dark"] .theme-icon-moon {
  display: block;
}

[data-theme="dark"] .theme-icon-sun {
  display: none;
}

/* --- Hero --- */
.hero {
  max-width: 1080px;
  width: 100%;
  margin: 0 auto;
  padding: 4.5rem 1.5rem 0;
  text-align: center;
}

.hero-lead {
  max-width: 52rem;
  margin: 0 auto;
  font-size: clamp(1rem, 2.2vw, 1.375rem);
  font-weight: 500;
  line-height: 1.5;
  color: var(--text-primary);
  /* 日本語の任意改行を禁止し、本文中の U+200B のみを改行位置として使う */
  word-break: keep-all;
  overflow-wrap: anywhere;
  text-wrap: balance;
}

/* --- Search & Category Filter Section --- */
.filter-section {
  max-width: 1080px;
  width: 100%;
  margin: 3rem auto 3.5rem;
  padding: 0 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
}

.search-box {
  position: relative;
  width: 100%;
  max-width: 420px;
}

.search-icon {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
  stroke-width: 2;
}

.search-input {
  width: 100%;
  padding: 0.7rem 1rem 0.7rem 2.75rem;
  border-radius: var(--radius-full);
  border: 1px solid transparent;
  background: var(--bg-control);
  color: var(--text-primary);
  font-size: 0.9375rem;
  font-family: inherit;
  transition: var(--transition-smooth);
  outline: none;
}

.search-input::placeholder {
  color: var(--text-muted);
}

.search-input:focus {
  background: var(--bg-base);
  border-color: var(--accent);
}

.category-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
}

.tag-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.4rem 1rem;
  border-radius: var(--radius-full);
  font-family: inherit;
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.tag-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-color-hover);
}

.tag-btn.active {
  background: var(--text-primary);
  color: var(--bg-base);
  border-color: var(--text-primary);
}

/* --- App Cards Grid --- */
.main-content {
  flex: 1;
  max-width: 1080px;
  width: 100%;
  margin: 0 auto;
  padding: 0 1.5rem 6rem;
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2.5rem 2rem;
}

/* Individual App Card */
.app-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: var(--transition-smooth);
  text-decoration: none;
}

.app-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-color-hover);
  box-shadow: var(--shadow-md);
}

/* Thumbnail Media Container */
.card-media {
  width: 100%;
  aspect-ratio: 3 / 2;
  overflow: hidden;
  background: var(--bg-surface);
}

.card-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.6s cubic-bezier(0.25, 0.1, 0.25, 1),
              filter 0.25s cubic-bezier(0.25, 0.1, 0.25, 1);
}

.app-card:hover .card-img {
  transform: scale(1.02);
}

/* Illustrations are drawn on a light canvas, so soften them against dark cards */
[data-theme="dark"] .card-img {
  filter: brightness(0.86) saturate(0.9);
}

[data-theme="dark"] .app-card:hover .card-img {
  filter: brightness(0.94) saturate(0.95);
}

/* Card Body Content */
.card-body {
  padding: 1.375rem 1.5rem;
  display: flex;
  flex-direction: column;
  flex: 1;
}

/* Category Eyebrow Label */
.card-badge {
  align-self: flex-start;
  margin-bottom: 0.5rem;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.card-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
  line-height: 1.3;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.card-title svg {
  flex-shrink: 0;
  width: 16px;
  height: 16px;
  stroke-width: 1.75;
  color: var(--text-muted);
  opacity: 0;
  transition: var(--transition-smooth);
}

.app-card:hover .card-title svg {
  opacity: 1;
}

.card-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 1.375rem;
  flex: 1;
}

/* Card Action Footer */
.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1rem;
  border-top: 1px solid var(--border-color);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--accent);
}

.card-action-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

.card-action-btn svg {
  width: 13px;
  height: 13px;
  stroke-width: 2;
  transition: transform 0.25s cubic-bezier(0.25, 0.1, 0.25, 1);
}

.app-card:hover .card-action-btn svg {
  transform: translateX(3px);
}

.card-url-domain {
  font-size: 0.8125rem;
  color: var(--text-muted);
  font-weight: 400;
}

/* No Results Message */
.no-results {
  grid-column: 1 / -1;
  text-align: center;
  padding: 5rem 1.5rem;
  color: var(--text-secondary);
  font-size: 0.9375rem;
  display: none;
}

.no-results i {
  font-size: 1.75rem;
  font-style: normal;
  margin-bottom: 0.75rem;
  display: block;
  opacity: 0.5;
}

/* --- Footer Section --- */
.footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border-color);
  padding: 2.5rem 1.5rem;
  text-align: center;
  margin-top: auto;
}

.footer-container {
  max-width: 1080px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.875rem;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.footer-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: var(--transition-smooth);
}

.footer-link:hover {
  color: var(--text-primary);
}

.footer-link svg {
  width: 16px;
  height: 16px;
}

.copyright {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Back to Top Floating Button */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--bg-header);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  opacity: 0;
  visibility: hidden;
  transition: var(--transition-smooth);
  z-index: 90;
}

.back-to-top svg {
  width: 17px;
  height: 17px;
  stroke-width: 2;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  color: var(--text-primary);
  border-color: var(--border-color-hover);
}

/* --- Responsive Layout Adjustments --- */
@media (max-width: 768px) {
  .cards-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .header-container {
    padding: 0.75rem 1.25rem;
  }

  .hero {
    padding: 2.75rem 1.25rem 0;
  }

  .filter-section {
    margin: 2.25rem auto 2.5rem;
    padding: 0 1.25rem;
  }

  .main-content {
    padding: 0 1.25rem 4rem;
  }

  .back-to-top {
    bottom: 1.25rem;
    right: 1.25rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}