/* ==========================================================================
   ChattyApps — Minimalist Engineering Portfolio
   Clean, typography-focused, craft-driven design
   ========================================================================== */

:root {
  /* Dark Mode (Default) - Pure Monochrome & Subtlety */
  --bg-body: #000000;
  --bg-surface: #0a0a0a;
  --bg-surface-hover: #141414;
  --bg-surface-active: #1c1c1c;
  --bg-badge: #141414;

  --border-subtle: #1c1c1c;
  --border-medium: #282828;
  --border-active: #404040;

  --text-primary: #ededed;
  --text-secondary: #8e8e8e;
  --text-muted: #5a5a5a;
  --text-link: #ffffff;

  --accent-green: #22c55e;
  --accent-blue: #3b82f6;

  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  --content-max-width: 740px;
  --transition: 0.18s ease;
}

/* Light Mode */
body.light-theme {
  --bg-body: #ffffff;
  --bg-surface: #f9f9f9;
  --bg-surface-hover: #f1f1f1;
  --bg-surface-active: #e8e8e8;
  --bg-badge: #f0f0f0;

  --border-subtle: #e5e5e5;
  --border-medium: #d4d4d4;
  --border-active: #a3a3a3;

  --text-primary: #111111;
  --text-secondary: #555555;
  --text-muted: #888888;
  --text-link: #000000;
}

/* ==========================================================================
   Base
   ========================================================================== */

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.65;
  padding: 60px 24px 120px 24px;
  transition: background-color var(--transition), color var(--transition);
}

.wrapper {
  max-width: var(--content-max-width);
  margin: 0 auto;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition), opacity var(--transition);
}

/* ==========================================================================
   Header
   ========================================================================== */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 56px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-subtle);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-icon {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
}

.brand-icon img, .brand-icon svg {
  width: 100%;
  height: 100%;
}

.brand-name {
  font-weight: 600;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 0.8rem;
  color: var(--text-secondary);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  padding: 4px 11px;
  border-radius: var(--radius-full);
}

.status-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--accent-green);
  box-shadow: 0 0 8px rgba(34, 197, 94, 0.6);
}

.theme-btn {
  background: transparent;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-secondary);
  transition: all var(--transition);
}

.theme-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-medium);
  background: var(--bg-surface);
}

.theme-btn svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

.sun-icon { display: none; }
.moon-icon { display: block; }
body.light-theme .sun-icon { display: block; }
body.light-theme .moon-icon { display: none; }

/* ==========================================================================
   Hero / Intro
   ========================================================================== */

.hero {
  margin-bottom: 56px;
}

.hero-title {
  font-size: 1.85rem;
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.3;
  margin-bottom: 18px;
  color: var(--text-primary);
}

.hero-bio {
  font-size: 1.02rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 24px;
}

.hero-links {
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
}

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-primary);
  padding-bottom: 2px;
  border-bottom: 1px solid var(--border-medium);
  transition: all var(--transition);
}

.link-arrow:hover {
  border-bottom-color: var(--text-primary);
  color: var(--text-link);
}

.link-arrow svg {
  transition: transform var(--transition);
}

.link-arrow:hover svg {
  transform: translate(2px, -2px);
}

/* ==========================================================================
   Section Headers & Tabs
   ========================================================================== */

.section {
  margin-bottom: 64px;
}

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 22px;
}

.section-title {
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text-primary);
}

.filter-group {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.filter-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 500;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition);
}

.filter-btn:hover {
  color: var(--text-secondary);
}

.filter-btn.active {
  color: var(--text-primary);
  background: var(--bg-surface);
  border-color: var(--border-subtle);
}

/* ==========================================================================
   Projects List
   ========================================================================== */

.projects-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.project-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  transition: all var(--transition);
  overflow: hidden;
}

.project-item:hover {
  border-color: var(--border-medium);
  background: var(--bg-surface-hover);
}

.project-item.expanded {
  border-color: var(--border-active);
}

/* Project Header / Row */
.project-row {
  padding: 18px 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  user-select: none;
  gap: 16px;
}

.project-leading {
  display: flex;
  align-items: center;
  gap: 16px;
  flex: 1;
  min-width: 0;
}

.project-avatar {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: var(--bg-badge);
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  overflow: hidden;
  transition: transform var(--transition), border-color var(--transition);
}

.project-item:hover .project-avatar {
  border-color: var(--border-medium);
  transform: scale(1.04);
}

.project-avatar img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

.project-info {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

.project-meta-line {
  display: flex;
  align-items: center;
  gap: 10px;
}

.project-title {
  font-size: 1.08rem;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.project-tag {
  font-size: 0.74rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  background: var(--bg-badge);
  border: 1px solid var(--border-subtle);
  padding: 1px 7px;
  border-radius: var(--radius-sm);
}

.project-desc-short {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.project-row-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.action-btn-group {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.action-btn-group.is-disabled {
  cursor: not-allowed;
}

.btn-view {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.8rem;
  font-weight: 500;
  font-family: inherit;
  color: var(--text-primary);
  background: var(--bg-badge);
  border: 1px solid var(--border-medium);
  padding: 5px 12px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  white-space: nowrap;
  text-decoration: none;
}

.btn-view:hover {
  background: var(--text-primary);
  color: var(--bg-body);
  border-color: var(--text-primary);
}

.btn-view.is-disabled {
  opacity: 0.45;
  cursor: not-allowed;
  pointer-events: none;
  background: var(--bg-badge);
  color: var(--text-muted);
  border-color: var(--border-subtle);
  transform: none !important;
}

.badge-unavailable {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  white-space: nowrap;
  letter-spacing: -0.01em;
  user-select: none;
}

.badge-unavailable::before {
  content: '';
  display: inline-block;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--text-muted);
  opacity: 0.6;
}

.btn-view-code {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: transparent;
  border: 1px solid var(--border-subtle);
  padding: 5px 10px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  white-space: nowrap;
}

.btn-view-code:hover {
  color: var(--text-primary);
  border-color: var(--border-medium);
  background: var(--bg-surface-hover);
}

.project-expand-icon {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  flex-shrink: 0;
  transition: transform var(--transition), color var(--transition);
}

.project-item:hover .project-expand-icon {
  color: var(--text-primary);
}

.project-item.expanded .project-expand-icon {
  transform: rotate(180deg);
  color: var(--text-primary);
}

/* Expanded Details Drawer */
.project-drawer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  border-top: 1px solid transparent;
}

.project-item.expanded .project-drawer {
  border-top-color: var(--border-subtle);
}

.drawer-content {
  padding: 24px 22px 26px 22px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.drawer-head-box {
  display: flex;
  align-items: center;
  gap: 14px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-subtle);
}

.drawer-avatar {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: var(--bg-badge);
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  overflow: hidden;
}

.drawer-avatar img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

.drawer-head-title {
  font-size: 1.12rem;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.01em;
  margin-bottom: 3px;
}

.drawer-head-meta {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.drawer-section-title {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 8px;
  font-weight: 600;
}

.drawer-text {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

.drawer-features {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.drawer-features li {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.55;
  position: relative;
  padding-left: 16px;
}

.drawer-features li::before {
  content: '–';
  position: absolute;
  left: 0;
  color: var(--text-muted);
}

.drawer-stack {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.stack-pill {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--text-secondary);
  background: var(--bg-badge);
  border: 1px solid var(--border-subtle);
  padding: 3px 8px;
  border-radius: var(--radius-sm);
}

.drawer-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 18px;
  border-top: 1px solid var(--border-subtle);
  gap: 14px;
  flex-wrap: wrap;
}

.drawer-actions-left {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.drawer-unavailable-group {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  cursor: not-allowed;
  flex-wrap: wrap;
}

.drawer-btn-view {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.84rem;
  font-weight: 600;
  font-family: inherit;
  color: var(--bg-body);
  background: var(--text-primary);
  border: 1px solid var(--text-primary);
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  text-decoration: none;
}

.drawer-btn-view:hover {
  opacity: 0.88;
  transform: translateY(-1px);
}

.drawer-btn-view.is-disabled {
  opacity: 0.45;
  cursor: not-allowed;
  pointer-events: none;
  background: var(--bg-badge);
  color: var(--text-muted);
  border: 1px solid var(--border-subtle);
  transform: none !important;
}

.drawer-btn-github {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.84rem;
  font-weight: 500;
  color: var(--text-primary);
  background: var(--bg-badge);
  border: 1px solid var(--border-medium);
  padding: 6px 13px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}

.drawer-btn-github:hover {
  border-color: var(--text-primary);
  background: var(--bg-surface-hover);
}

.drawer-nda-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.drawer-cta {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-primary);
  font-weight: 500;
  font-size: 0.86rem;
  transition: opacity var(--transition);
}

.drawer-cta:hover {
  opacity: 0.75;
}

/* ==========================================================================
   Stack & Competencies
   ========================================================================== */

.stack-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.stack-group {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 20px;
}

.stack-group-title {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 12px;
  font-weight: 600;
}

.stack-items-list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

/* ==========================================================================
   Contact / Footer
   ========================================================================== */

.contact-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 26px;
  margin-bottom: 48px;
}

.contact-text {
  font-size: 0.98rem;
  color: var(--text-secondary);
  margin-bottom: 18px;
  line-height: 1.6;
}

.contact-actions {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 24px;
  border-top: 1px solid var(--border-subtle);
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Project Landing Pages (e.g. yttvaf.html)
   ========================================================================== */

.landing-nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 40px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-subtle);
}

.landing-nav-left {
  display: flex;
  align-items: center;
  gap: 14px;
}

.landing-back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition);
  text-decoration: none;
}

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

.landing-hero {
  margin-bottom: 48px;
}

.landing-head {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  margin-bottom: 24px;
}

.landing-app-icon {
  width: 72px;
  height: 72px;
  border-radius: 16px;
  border: 1px solid var(--border-medium);
  background: var(--bg-surface);
  box-shadow: var(--shadow-sm);
  flex-shrink: 0;
  object-fit: contain;
}

.landing-title-wrap {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.landing-meta-tags {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.landing-title {
  font-size: 2.1rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  line-height: 1.2;
}

.landing-lead {
  font-size: 1.05rem;
  line-height: 1.68;
  color: var(--text-secondary);
  margin-bottom: 28px;
}

.landing-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 36px;
}

.btn-primary-open {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--bg-body);
  background: var(--text-primary);
  border: 1px solid var(--text-primary);
  padding: 10px 22px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  text-decoration: none;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
}

.btn-primary-open:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

.btn-secondary-action {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-primary);
  background: var(--bg-badge);
  border: 1px solid var(--border-medium);
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  text-decoration: none;
}

.btn-secondary-action:hover {
  background: var(--bg-surface-hover);
  border-color: var(--text-primary);
  transform: translateY(-1px);
}

.landing-media-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: 48px;
  box-shadow: var(--shadow-sm);
}

.landing-media-box img {
  width: 100%;
  height: auto;
  display: block;
  border-bottom: 1px solid var(--border-subtle);
}

.landing-media-caption {
  padding: 12px 18px;
  font-size: 0.82rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-surface);
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-bottom: 48px;
}

.metric-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.metric-val {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  font-family: var(--font-mono);
}

.metric-lbl {
  font-size: 0.76rem;
  color: var(--text-muted);
  line-height: 1.35;
}

.landing-feature-item {
  padding: 18px 0;
  border-bottom: 1px solid var(--border-subtle);
}

.landing-feature-item:last-child {
  border-bottom: none;
}

.landing-feature-title {
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.landing-feature-desc {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.landing-table-wrap {
  width: 100%;
  overflow-x: auto;
  margin-bottom: 32px;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
}

.landing-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  text-align: left;
}

.landing-table th {
  background: var(--bg-badge);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-subtle);
}

.landing-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-secondary);
}

.landing-table tr:last-child td {
  border-bottom: none;
}

.kbd-tag {
  display: inline-block;
  padding: 3px 8px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-primary);
  background: var(--bg-surface);
  border: 1px solid var(--border-medium);
  border-radius: 4px;
  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.08);
}

.steps-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: 40px;
}

.step-card {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 16px;
}

.step-num {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--bg-badge);
  border: 1px solid var(--border-medium);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  font-weight: 600;
  flex-shrink: 0;
  font-family: var(--font-mono);
}

.step-content {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.step-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
}

.step-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* Responsive */
@media (max-width: 600px) {
  body {
    padding: 36px 16px 80px 16px;
  }
  .hero-title {
    font-size: 1.55rem;
  }
  .stack-grid {
    grid-template-columns: 1fr;
  }
  .project-row {
    padding: 16px;
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
  .project-row-actions {
    width: 100%;
    justify-content: flex-start;
    gap: 8px;
  }
  .project-expand-icon {
    margin-left: auto;
  }
  .drawer-content {
    padding: 18px 16px;
  }
  .drawer-footer {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
  .drawer-actions-left {
    width: 100%;
  }
  .landing-title {
    font-size: 1.65rem;
  }
  .landing-head {
    flex-direction: column;
    gap: 14px;
  }
  .metrics-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}