:root {
  --bg: #ffffff;
  --bg-subtle: #f8fafc;
  --border: #e2e8f0;
  --text: #0f172a;
  --text-muted: #64748b;
  --accent: #2563eb;
  --accent-bg: #eff6ff;
  --max-width: 960px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Pretendard", sans-serif;
  line-height: 1.6;
}

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

.wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* header */

header.site-header {
  border-bottom: 1px solid var(--border);
}

header.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1.25rem;
  padding-bottom: 1.25rem;
}

.brand {
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
}

.lang-toggle {
  display: flex;
  gap: 0.5rem;
  font-size: 0.85rem;
}

.lang-toggle a,
.lang-toggle span {
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
  color: var(--text-muted);
}

.lang-toggle .current {
  background: var(--accent-bg);
  color: var(--accent);
  font-weight: 600;
}

/* hero */

.hero {
  padding: 4.5rem 0 3.5rem;
}

.hero .eyebrow {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.75rem;
}

.hero h1 {
  font-size: 2.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 1rem;
}

.hero p.lede {
  font-size: 1.05rem;
  color: var(--text-muted);
  margin: 0 0 1.75rem;
}

.hero .cta-row {
  display: flex;
  gap: 0.75rem;
}

.btn {
  display: inline-block;
  padding: 0.65rem 1.25rem;
  border-radius: 0.5rem;
  font-size: 0.9rem;
  font-weight: 600;
}

.btn-primary {
  background: var(--text);
  color: #ffffff;
}

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

/* project cards */

.projects {
  padding: 1rem 0 5rem;
}

.projects h2 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-muted);
  margin: 0 0 1.25rem;
}

.card-grid {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.project-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1.75rem 2rem;
  background: var(--bg);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

@media (max-width: 700px) {
  .project-card {
    flex-direction: column;
    align-items: stretch;
    gap: 1.25rem;
  }
}

.project-card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 16px rgba(15, 23, 42, 0.06);
}

.project-card .card-main {
  flex: 1;
  min-width: 0;
}

.project-card .tag {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.project-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 0 0 0.5rem;
  letter-spacing: -0.01em;
}

.project-card .summary {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin: 0;
}

.project-card .card-aside {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.75rem;
  flex-shrink: 0;
  width: 240px;
}

@media (max-width: 700px) {
  .project-card .card-aside {
    align-items: flex-start;
    width: auto;
  }
}

.project-card .more {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
}

/* footer */

footer.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
}

footer.site-footer .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-muted);
}

footer.site-footer a {
  font-weight: 600;
  color: var(--text);
}

/* project detail page */

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 1.75rem 0 1rem;
}

.breadcrumb a {
  color: var(--text-muted);
}

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

.breadcrumb .crumb-sep {
  color: var(--border);
}

.breadcrumb .crumb-current {
  color: var(--text);
  font-weight: 600;
}

.page-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 3rem;
  margin-bottom: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.page-nav-btn {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
}

.page-nav-btn:hover {
  color: var(--accent);
}

.page-nav-btn.next {
  margin-left: auto;
}

.project-hero {
  padding-bottom: 2.5rem;
  border-bottom: 1px solid var(--border);
}

.project-hero .tag {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.project-hero h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 1rem;
}

.project-hero .lede {
  font-size: 1.05rem;
  color: var(--text-muted);
  margin: 0 0 1.5rem;
}

.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.badge {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-bg);
  border-radius: 999px;
  padding: 0.4rem 0.9rem;
}

.prose {
  padding: 2rem 0;
}

.prose + .prose {
  border-top: 1px solid var(--border);
}

.prose h2 {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 0 0 1.25rem;
}

.prose h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 2rem 0 0.85rem;
}

.prose p {
  margin: 0 0 1rem;
  color: var(--text);
}

.prose ul,
.prose ol {
  margin: 0 0 1rem;
  padding-left: 1.4rem;
}

.prose li {
  margin-bottom: 0.6rem;
}

.prose li strong {
  color: var(--text);
}

.owning-note {
  font-size: 0.85rem;
  color: var(--text-muted);
  background: var(--bg-subtle);
  border-left: 3px solid var(--accent);
  padding: 0.75rem 1rem;
  margin: 0 0 1.5rem;
}

.diagram-block {
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1.5rem;
  margin: 1.5rem 0;
  background: var(--bg-subtle);
  overflow-x: auto;
}

.diagram-block .mermaid {
  display: flex;
  justify-content: center;
}

.figure-block {
  margin: 1.5rem 0;
}

.figure-block img {
  width: 100%;
  border-radius: 0.75rem;
}

.figure-block figcaption {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.6rem;
  text-align: center;
}

.result-columns {
  display: grid;
  grid-template-columns: minmax(260px, 340px) 1fr;
  gap: 2rem;
  align-items: start;
  margin-bottom: 1.5rem;
}

@media (max-width: 700px) {
  .result-columns {
    grid-template-columns: 1fr;
  }
}

.result-columns img,
.result-columns video {
  width: 100%;
  border-radius: 0.75rem;
  display: block;
}

.field-columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  align-items: center;
  margin: 1.5rem 0;
}

@media (max-width: 700px) {
  .field-columns {
    grid-template-columns: 1fr;
  }
}

.field-columns .diagram-block {
  margin: 0;
}

.stat-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  margin: 1.25rem 0 1.75rem;
}

.stat-table th,
.stat-table td {
  border: 1px solid var(--border);
  padding: 0.6rem 0.75rem;
  text-align: left;
}

.stat-table th {
  background: var(--bg-subtle);
  font-weight: 600;
  color: var(--text-muted);
}

/* action link cards (sub-page navigation) */

.action-links {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  margin: 0 0 1rem;
}

.action-link-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  border: 1px solid var(--border);
  border-radius: 0.65rem;
  padding: 1.1rem 1.4rem;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.action-link-card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 16px rgba(15, 23, 42, 0.06);
}

.action-link-card .step {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent);
  background: var(--accent-bg);
  border-radius: 999px;
  width: 1.6rem;
  height: 1.6rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.action-link-card .text {
  flex: 1;
  min-width: 0;
}

.action-link-card .title {
  display: block;
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: 0.35rem;
}

.action-link-card .desc {
  display: block;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.action-link-card .arrow {
  color: var(--text-muted);
  font-weight: 600;
  flex-shrink: 0;
}

/* video demo */

.demo-video {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 0.75rem;
}

/* chat mock (reconstructed UI example) */

.chat-mock {
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  overflow: hidden;
  background: var(--bg);
  font-size: 0.85rem;
  max-width: 340px;
  margin: 0 auto;
}

.chat-mock-header {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--border);
}

.chat-mock-back {
  color: var(--text-muted);
  font-size: 1rem;
}

.chat-mock-header-text {
  flex: 1;
}

.chat-mock-title {
  font-weight: 700;
  font-size: 0.9rem;
}

.chat-mock-sub {
  font-size: 0.7rem;
  color: var(--text-muted);
}

.chat-mock-more {
  color: var(--text-muted);
}

.chat-mock-product {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 1rem;
  background: var(--bg-subtle);
}

.chat-mock-product .chat-mock-thumb {
  width: 36px;
  height: 36px;
  border-radius: 0.4rem;
  background: var(--border);
  object-fit: cover;
  flex-shrink: 0;
}

.chat-mock-product-title {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 0.15rem;
}

.chat-mock-product-price {
  font-size: 0.85rem;
  font-weight: 700;
}

.chat-mock-product-price .chat-mock-link {
  font-weight: 400;
  font-size: 0.7rem;
  color: var(--accent);
  margin-left: 0.4rem;
}

.chat-mock-product-shipping {
  font-size: 0.7rem;
  color: var(--text-muted);
}

.chat-mock-detail-tab {
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-muted);
  padding: 0.5rem;
  border-bottom: 1px solid var(--border);
}

.chat-mock-body {
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.chat-mock-timestamp {
  text-align: center;
  font-size: 0.65rem;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.chat-bubble-group {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  align-items: flex-start;
}

.chat-bubble-fragment {
  margin-top: -0.22rem;
  padding: 0.15rem 0.6rem;
  font-size: 0.8rem;
}

.chat-bubble {
  display: inline-block;
  padding: 0.5rem 0.75rem;
  border-radius: 0.9rem;
  font-size: 0.8rem;
  line-height: 1.4;
  max-width: 220px;
}

.chat-bubble-seller {
  background: var(--bg-subtle);
  color: var(--text);
  border-bottom-left-radius: 0.25rem;
}

.chat-bubble-buyer {
  background: var(--text);
  color: #ffffff;
  align-self: flex-end;
  border-bottom-right-radius: 0.25rem;
  margin-left: auto;
}

.chat-detection-card {
  position: relative;
  background: #fef2f2;
  border: 1px solid #fecaca;
  border-radius: 0.6rem;
  padding: 0.75rem 0.85rem;
  margin-top: 0.4rem;
  font-size: 0.75rem;
  line-height: 1.5;
  color: #7f1d1d;
}

.chat-detection-label {
  position: absolute;
  top: -0.6rem;
  right: 0.6rem;
  background: #ef4444;
  color: #ffffff;
  font-size: 0.6rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
}

.chat-mock-input-bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.65rem 1rem;
  border-top: 1px solid var(--border);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.chat-mock-input-placeholder {
  flex: 1;
}

.chat-mock-send {
  color: var(--text);
}

/* swipeable example cards (result section) */

.result-swipe-wrap {
  min-width: 0;
}

.swipe-track {
  display: flex;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.swipe-track::-webkit-scrollbar {
  display: none;
}

.swipe-card {
  flex: 0 0 100%;
  scroll-snap-align: center;
  margin: 0;
}

.swipe-dots {
  display: flex;
  justify-content: center;
  gap: 0.4rem;
  margin-top: 0.75rem;
}

.swipe-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  border: none;
  padding: 0;
  background: var(--border);
  cursor: pointer;
}

.swipe-dot.active {
  background: var(--accent);
}

/* calculator mock (reconstructed UI example) */

.calc-mock {
  background: #000000;
  border-radius: 1.25rem;
  padding: 1.25rem 1rem;
  max-width: 300px;
  margin: 0 auto;
  box-sizing: border-box;
}

.calc-mock-history {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0.3rem;
  margin-bottom: 0.5rem;
  font-size: 0.85rem;
  color: #6b6b6b;
}

.calc-mock-display {
  text-align: right;
  color: #ffffff;
  font-size: 2.4rem;
  font-weight: 300;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.calc-mock-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.6rem;
}

.calc-mock-btn {
  aspect-ratio: 1;
  border-radius: 50%;
  border: none;
  color: #ffffff;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.calc-mock-btn.fn {
  background: #4a4a4c;
}

.calc-mock-btn.digit {
  background: #333335;
}

.calc-mock-btn.op {
  background: #ff9f0a;
  font-size: 1.3rem;
}