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

/* ===== Theme Variables ===== */
:root {
  --bg: #000000;
  --bg-panel: #111111;
  --bg-glass: #1a1a1a;
  --card-hover: #222222;
  --border: #2a2a2a;
  --border-bright: rgba(139, 126, 200, 0.25);
  --fg: #e8e0d4;
  --fg-muted: #8a8278;
  --accent: #8b7ec8;
  --accent-rgb: 139, 126, 200;
  --accent-dim: rgba(139, 126, 200, 0.12);
  --font-brand: 'Righteous', cursive;
  --font-body: 'Source Sans 3', 'Segoe UI', system-ui, -apple-system, sans-serif;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-med: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Light mode — white background, black text */
html.light {
  --bg: #ffffff;
  --bg-panel: #ffffff;
  --bg-glass: #f0eeeb;
  --card-hover: #e8e5e0;
  --border: #d5d0c8;
  --border-bright: rgba(139, 126, 200, 0.3);
  --fg: #000000;
  --fg-muted: #555555;
  --accent-dim: rgba(139, 126, 200, 0.08);
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.75;
  color: var(--fg);
  background: var(--bg);
  transition: background 0.35s ease, color 0.35s ease;
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(139, 126, 200, 0.25); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(139, 126, 200, 0.4); }
::selection { background: rgba(139, 126, 200, 0.3); color: var(--fg); }

/* ===== Page Layout ===== */
.page-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}
.body-layout {
  display: flex;
  flex: 1;
}

/* ===== Header ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--bg-panel);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  padding: 0 24px;
}
.header-left {
  display: flex;
  align-items: center;
  gap: 32px;
}
.brand-link {
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
}
.brand-link:hover .brand-title { text-shadow: 0 0 16px rgba(139,126,200,0.35); }
.brand-link:hover .brand-subtitle { color: var(--fg); }
.brand-title {
  font-family: var(--font-brand);
  font-size: 24px;
  letter-spacing: 1.5px;
  color: var(--accent);
  line-height: 1.1;
  transition: text-shadow 0.3s;
}
.brand-subtitle {
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--fg-muted);
  margin-top: 2px;
  transition: color 0.2s;
}

/* Header nav */
.header-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}
.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 12px;
  font-size: 14px;
  font-weight: 500;
  color: var(--fg-muted);
  text-decoration: none;
  border-radius: 6px;
  border: none;
  background: none;
  cursor: pointer;
  font-family: var(--font-body);
  transition: all var(--transition-fast);
}
.nav-link:hover {
  color: var(--fg);
  background: var(--card-hover);
}

/* Dropdown */
.dropdown { position: relative; }
.chevron { transition: transform 0.2s; }
.dropdown.open .chevron { transform: rotate(180deg); }
.dropdown-menu {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  min-width: 280px;
  background: var(--bg-panel);
  border: 1px solid var(--border-bright);
  border-radius: var(--radius-md);
  box-shadow: 0 8px 32px rgba(0,0,0,0.45), 0 0 0 1px rgba(var(--accent-rgb), 0.06);
  z-index: 50;
  overflow: hidden;
  display: none;
  animation: dropdown-enter 0.18s cubic-bezier(0.16, 1, 0.3, 1);
}
html.light .dropdown-menu {
  box-shadow: 0 8px 32px rgba(0,0,0,0.08), 0 0 0 1px rgba(var(--accent-rgb), 0.08);
}
.dropdown.open .dropdown-menu { display: block; }
@keyframes dropdown-enter {
  from { opacity: 0; transform: translateY(-6px) scale(0.97); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}
.dropdown-item {
  display: block;
  padding: 10px 16px;
  font-size: 13px;
  color: var(--fg);
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: all var(--transition-fast);
}
.dropdown-item:hover {
  background: var(--card-hover);
  border-left-color: var(--accent);
  color: #fff;
}
html.light .dropdown-item:hover { color: var(--accent); }

/* Theme toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border: none;
  background: none;
  border-radius: 6px;
  cursor: pointer;
  color: var(--fg-muted);
  transition: all var(--transition-fast);
}
.theme-toggle:hover {
  color: var(--fg);
  background: var(--card-hover);
}
/* Show moon in dark mode, sun in light mode */
html.dark .icon-sun { display: none; }
html.dark .icon-moon { display: block; }
html.light .icon-sun { display: block; }
html.light .icon-moon { display: none; }

/* ===== Sidebar ===== */
.sidebar {
  width: 240px;
  min-width: 240px;
  background: var(--bg-panel);
  border-right: 1px solid var(--border);
  position: sticky;
  top: 56px;
  height: calc(100vh - 56px);
  overflow-y: auto;
  flex-shrink: 0;
  padding-top: 16px;
}
.sidebar-section { margin-bottom: 16px; }
.sidebar-section:first-child {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--bg-panel);
  padding: 16px 0 0;
  margin-bottom: 0;
}
.sidebar-section:first-child::after {
  content: '';
  display: block;
  height: 1px;
  margin: 0 24px;
  background: linear-gradient(90deg, transparent, var(--border-bright), transparent);
}
.sidebar-section:first-child .sidebar-link {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 16px;
}
.sidebar-link .nav-arrow {
  margin-left: auto;
  flex-shrink: 0;
  opacity: 0.5;
  transition: opacity 0.2s, transform 0.2s;
}
.sidebar-link:hover .nav-arrow {
  opacity: 1;
  transform: translateX(-2px);
}
.sidebar-heading {
  padding: 8px 24px 6px;
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--fg-muted);
}
.sidebar-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 24px;
  font-size: 13px;
  font-weight: 500;
  color: var(--fg);
  text-decoration: none;
  border-left: 3px solid transparent;
  transition: all var(--transition-fast);
}
.sidebar-link:hover {
  background: var(--card-hover);
  border-left-color: var(--accent);
}
.sidebar-link.active {
  color: var(--accent);
  border-left-color: var(--accent);
  background: var(--accent-dim);
  pointer-events: none;
  cursor: default;
}
.sidebar-link.sub {
  padding-left: 36px;
  font-size: 12px;
  font-weight: 400;
  color: var(--fg-muted);
}
.sidebar-link.sub:hover {
  color: var(--fg);
  background: var(--card-hover);
  border-left-color: var(--accent);
}
.sidebar-icon {
  width: 18px;
  height: 18px;
  object-fit: contain;
  flex-shrink: 0;
}

/* ===== Sidebar Preview Popup ===== */
.sidebar-preview {
  position: fixed;
  width: 260px;
  background: var(--bg-panel);
  border: 1px solid var(--border-bright);
  border-radius: var(--radius-md);
  box-shadow: 0 8px 32px rgba(0,0,0,0.45), 0 0 0 1px rgba(var(--accent-rgb), 0.06);
  z-index: 60;
  overflow: hidden;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
  transform: translateX(-6px);
}
html.light .sidebar-preview {
  box-shadow: 0 8px 32px rgba(0,0,0,0.08), 0 0 0 1px rgba(var(--accent-rgb), 0.08);
}
.sidebar-preview.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateX(0);
}
.sidebar-preview-img {
  width: 100%;
  height: 146px;
  overflow: hidden;
}
.sidebar-preview-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.sidebar-preview-info {
  padding: 12px 14px 14px;
}
.sidebar-preview-title {
  font-family: var(--font-brand);
  font-size: 14px;
  letter-spacing: 0.5px;
  color: var(--accent);
  margin-bottom: 3px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.sidebar-preview-subtitle {
  font-size: 10px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--fg-muted);
  margin-bottom: 8px;
}
.sidebar-preview-desc {
  font-size: 12px;
  line-height: 1.55;
  color: var(--fg-muted);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ===== Main Content ===== */
.main-content {
  flex: 1;
  padding: 24px 40px 96px;
  background: var(--bg);
  min-height: calc(100vh - 56px);
}

/* ===== Overview Heading ===== */
.overview-heading {
  margin-bottom: 24px;
}
.overview-heading .section-divider {
  margin-top: 20px;
  margin-bottom: 0;
}
.overview-title {
  font-family: var(--font-brand);
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  letter-spacing: 0.04em;
  line-height: 1;
  background: linear-gradient(180deg, #8b7ec8 0%, #8b7ec8 40%, rgba(139, 126, 200, 0.3) 70%, rgba(139, 126, 200, 0) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ===== Preview Row ===== */
.preview-row {
  display: flex;
  gap: 32px;
  margin-bottom: 32px;
}
.preview-window {
  position: relative;
  width: 55%;
  aspect-ratio: 16 / 9;
  border-radius: 0;
  overflow: hidden;
  border: none;
  background: var(--bg-panel);
  flex-shrink: 0;
  text-decoration: none;
  display: block;
}
.preview-window img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 0.7s;
}
.preview-window:hover img { transform: scale(1.05); }
.preview-gradient {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0,0,0,0.75) 0%, rgba(0,0,0,0.5) 35%, rgba(0,0,0,0.1) 55%, transparent 70%);
  mix-blend-mode: multiply;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.4s ease;
}
html.light .preview-gradient {
  background: linear-gradient(to top, rgba(0,0,0,0.55) 0%, rgba(0,0,0,0.35) 35%, rgba(0,0,0,0.05) 55%, transparent 70%);
}
.preview-window:hover .preview-gradient {
  opacity: 1;
}

.preview-text-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 28px 20px 20px;
  z-index: 2;
  display: flex;
  flex-direction: column;
  gap: 4px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.4s ease;
}
.preview-window:hover .preview-text-overlay {
  opacity: 1;
}
.preview-text-title {
  font-family: var(--font-brand);
  font-size: 20px;
  letter-spacing: 1px;
  color: #ffffff;
  text-shadow: 0 1px 4px rgba(0,0,0,0.5);
  max-width: 60%;
  line-height: 1.3;
}
.preview-text-tagline {
  font-size: 12px;
  color: rgba(255,255,255,0.6);
  line-height: 1.5;
  margin-top: 4px;
  max-width: 60%;
}
.preview-text-subtitle {
  font-size: 12px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: rgba(255,255,255,0.7);
  text-shadow: 0 1px 3px rgba(0,0,0,0.4);
}
.preview-description {
  width: 45%;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.project-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}
.project-icon-wrap {
  width: 48px;
  height: 48px;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg-glass);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.project-icon-wrap img {
  width: 36px;
  height: 36px;
  object-fit: contain;
}
.project-title {
  font-family: var(--font-brand);
  font-size: 28px;
  letter-spacing: 1px;
  color: var(--accent);
}
.project-subtitle {
  font-size: 12px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--fg-muted);
  margin-top: 2px;
}
.project-desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--fg);
  margin-bottom: 16px;
}
.project-tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}
.tag-pill {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  font-size: 11px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  background: var(--accent-dim);
  color: var(--accent);
  border: 1px solid var(--border-bright);
  transition: all var(--transition-fast);
}
.tag-pill:hover {
  background: rgba(var(--accent-rgb), 0.2);
  border-color: var(--accent);
}
.learn-more-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 600;
  font-family: var(--font-body);
  color: #fff;
  background: linear-gradient(135deg, #8b7ec8, #6c5ce7, #a78bfa);
  border: none;
  border-radius: 8px;
  text-decoration: none;
  cursor: pointer;
  width: fit-content;
  align-self: flex-start;
  transition: all 0.2s;
}
.learn-more-btn:hover {
  filter: brightness(1.15);
  box-shadow: 0 4px 16px rgba(var(--accent-rgb), 0.3);
  transform: translateY(-1px);
}

/* ===== Divider ===== */
.section-divider {
  width: 100%;
  height: 1px;
  margin-bottom: 32px;
  background: linear-gradient(90deg, transparent, var(--border-bright), transparent);
}

/* ===== Selection Area ===== */
.selection-area { }
.selection-group { margin-bottom: 24px; }
.selection-heading {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--fg-muted);
  margin-bottom: 12px;
}
.selection-grid {
  display: grid;
  gap: 16px;
}
.three-col { grid-template-columns: repeat(3, 1fr); }
.project-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-panel);
  cursor: pointer;
  text-align: left;
  font-family: var(--font-body);
  transition: all var(--transition-med);
}
.project-btn:hover {
  border-color: var(--accent);
}
.project-btn.active {
  border-color: var(--accent);
  background: var(--accent-dim);
  box-shadow: 0 0 12px rgba(var(--accent-rgb), 0.15);
}
.btn-icon-wrap {
  width: 40px;
  height: 40px;
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg-glass);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.btn-icon-wrap img {
  width: 28px;
  height: 28px;
  object-fit: contain;
}
.btn-text {
  flex: 1;
  min-width: 0;
}
.btn-title {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--fg);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: color 0.2s;
}
.project-btn.active .btn-title { color: var(--accent); }
.btn-subtitle {
  display: block;
  font-size: 11px;
  color: var(--fg-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.btn-indicator {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
  opacity: 0;
  transition: opacity 0.2s;
}
.project-btn.active .btn-indicator { opacity: 1; }

/* ===== Footer ===== */
.site-footer {
  background: var(--bg-panel);
  border-top: 1px solid var(--border);
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  max-width: 1600px;
  margin: 0 auto;
}
.copyright {
  font-size: 12px;
  color: var(--fg-muted);
}
.go-top-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  font-size: 12px;
  font-family: var(--font-body);
  color: var(--fg-muted);
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.go-top-btn:hover {
  color: var(--accent);
  border-color: var(--accent);
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .body-layout { flex-direction: column; }
  .sidebar {
    width: 100%;
    min-width: 100%;
    height: auto;
    position: relative;
    top: 0;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  .main-content { padding: 32px 24px 64px; }
  .preview-row { flex-direction: column; }
  .preview-window { width: 100%; }
  .preview-description { width: 100%; }
  .three-col { grid-template-columns: 1fr; }
  .ux-design-grid { grid-template-columns: 1fr; }
}

/* ===== UX Design Section ===== */
.ux-design-section {
  scroll-margin-top: 72px;
}
.ux-design-title {
  font-family: var(--font-brand);
  font-size: 28px;
  letter-spacing: 1px;
  color: var(--accent);
  margin-bottom: 8px;
}
.ux-design-desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--fg-muted);
  margin-bottom: 24px;
  max-width: 640px;
}
.ux-design-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}
.ux-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 20px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-panel);
  text-decoration: none;
  transition: all var(--transition-med);
}
.ux-card:hover {
  border-color: var(--accent);
  background: var(--accent-dim);
  box-shadow: 0 0 12px rgba(var(--accent-rgb), 0.1);
}
.ux-card-icon {
  width: 44px;
  height: 44px;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg-glass);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.ux-card-icon img {
  width: 32px;
  height: 32px;
  object-fit: contain;
}
.ux-card-info {
  flex: 1;
  min-width: 0;
}
.ux-card-title {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--fg);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: color 0.2s;
}
.ux-card:hover .ux-card-title { color: var(--accent); }
.ux-card-subtitle {
  display: block;
  font-size: 11px;
  color: var(--fg-muted);
  margin-top: 2px;
}
.ux-card-arrow {
  flex-shrink: 0;
  color: var(--fg-muted);
  transition: color 0.2s, transform 0.2s;
}
.ux-card:hover .ux-card-arrow {
  color: var(--accent);
  transform: translateX(3px);
}