/* ==========================================================================
   CST Website - Text-First Minimalist Theme
   Simple, Fast, High-Contrast & Legible
   ========================================================================== */

/* 1. Root Design Tokens & Variables */
:root {
  --bg-color: #ffffff;
  --bg-alt: #f8fafc;
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-light: #64748b;
  --border-color: #e2e8f0;
  --border-dark: #cbd5e1;
  --accent-color: #1e40af;
  --accent-hover: #1d4ed8;
  --accent-bg: #eff6ff;
  --card-bg: #ffffff;
  --code-bg: #f1f5f9;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, SF Mono, Menlo, Consolas, "Liberation Mono", monospace;

  --container-width: 920px;
  --header-height: 72px;
  --radius-sm: 4px;
  --radius-md: 8px;
}

/* Dark Mode Color Palette Preference */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-color: #0b0f19;
    --bg-alt: #111827;
    --text-main: #f8fafc;
    --text-muted: #cbd5e1;
    --text-light: #94a3b8;
    --border-color: #1e293b;
    --border-dark: #334155;
    --accent-color: #60a5fa;
    --accent-hover: #93c5fd;
    --accent-bg: #1e293b;
    --card-bg: #111827;
    --code-bg: #1e293b;
  }
}

/* 2. Global Reset & Base Styles */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 1.05rem;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* 3. Site Wrapper & Layout Container */
.site-wrapper {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.site-main {
  flex: 1;
  padding-top: 2.5rem;
  padding-bottom: 4rem;
}

/* 4. Top Header & Navigation */
.site-header {
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.site-brand {
  display: flex;
  align-items: center;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-main);
}

.brand-logo {
  height: 32px;
  width: auto;
  display: block;
}

.light-mode-logo {
  display: block;
}

.dark-mode-logo {
  display: none;
}

@media (prefers-color-scheme: dark) {
  .light-mode-logo {
    display: none;
  }
  .dark-mode-logo {
    display: block;
  }
}

.brand-text {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--text-main);
}

.brand-subtitle {
  font-size: 0.75rem;
  color: var(--text-light);
  font-weight: 500;
  line-height: 1.2;
}

/* Header Navigation Links */
.site-nav {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-link {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.25rem 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.nav-link:hover {
  color: var(--text-main);
}

.nav-link.active {
  color: var(--accent-color);
  border-bottom-color: var(--accent-color);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  flex-direction: column;
  gap: 4px;
}

.hamburger-bar {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--text-main);
}

@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .site-nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
    padding: 1.5rem;
  }

  .site-nav.nav-open {
    display: block;
  }

  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: 1.25rem;
  }

  .nav-link {
    font-size: 1.1rem;
  }
}

/* 5. Typography Standards */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.02em;
}

h1 { font-size: 2.25rem; margin-bottom: 1rem; }
h2 { font-size: 1.65rem; margin-top: 2rem; margin-bottom: 1rem; }
h3 { font-size: 1.25rem; margin-top: 1.5rem; margin-bottom: 0.75rem; }
h4 { font-size: 1.1rem; margin-top: 1.25rem; margin-bottom: 0.5rem; }

p {
  margin-bottom: 1.25rem;
  color: var(--text-main);
}

a {
  color: var(--accent-color);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.15s ease;
}

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

hr, .section-divider {
  border: none;
  border-top: 1px solid var(--border-color);
  margin: 2.5rem 0;
}

/* 6. Buttons & Badges */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.25rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

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

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

.btn-outline {
  background-color: transparent;
  color: var(--text-main);
  border: 1px solid var(--border-dark);
}

.btn-outline:hover {
  background-color: var(--bg-alt);
  border-color: var(--text-main);
}

.btn-text {
  background-color: transparent;
  color: var(--accent-color);
  border: none;
  padding-left: 0;
  padding-right: 0;
}

.btn-sm {
  padding: 0.4rem 0.85rem;
  font-size: 0.85rem;
}

.badge-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-color);
  background-color: var(--accent-bg);
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
}

.tag-pill {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-light);
  background-color: var(--bg-alt);
  border: 1px solid var(--border-color);
  padding: 0.2rem 0.55rem;
  border-radius: var(--radius-sm);
}

/* 7. Home Page Hero & Sections */
.hero-section {
  padding: 2.5rem 0 3.5rem;
  border-bottom: 1px solid var(--border-color);
}

.hero-title {
  font-size: 2.5rem;
  line-height: 1.2;
  margin-bottom: 1.25rem;
  letter-spacing: -0.03em;
}

.hero-description {
  font-size: 1.2rem;
  color: var(--text-muted);
  max-width: 780px;
  line-height: 1.6;
  margin-bottom: 2rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
}

.home-section {
  padding: 3.5rem 0;
  border-bottom: 1px solid var(--border-color);
}

.home-section:last-of-type {
  border-bottom: none;
}

.section-header-block {
  margin-bottom: 2rem;
}

.section-title {
  font-size: 1.75rem;
  margin-top: 0;
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
  color: var(--text-main);
}

.section-lead {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 750px;
}

.section-header-flex {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.75rem;
}

.section-header-flex .section-title {
  margin-bottom: 0;
}

.section-all-link {
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
}

/* 8. Flat Services Section (Single Level) */
.flat-services-container {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.flat-service-block {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--accent-color);
  border-radius: var(--radius-md);
  padding: 1.75rem;
}

.service-block-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.service-badge {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--accent-color);
  font-size: 1rem;
}

.flat-service-block h3 {
  font-size: 1.35rem;
  margin: 0;
}

.service-block-intro {
  font-size: 1.05rem;
  color: var(--text-main);
  line-height: 1.6;
  margin-bottom: 1rem;
}

.service-block-details h4 {
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-light);
  margin-top: 1rem;
  margin-bottom: 0.75rem;
}

.flat-feature-list {
  list-style: disc;
  padding-left: 1.25rem;
  margin-bottom: 0.5rem;
}

.flat-feature-list li {
  margin-bottom: 0.5rem;
  color: var(--text-muted);
  font-size: 0.975rem;
}

.flat-feature-list li strong {
  color: var(--text-main);
}

/* 9. Flat Projects Section (Single Level) */
.flat-projects-container {
  display: flex;
  flex-direction: column;
  gap: 2.25rem;
}

.flat-project-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 2rem;
}

.project-header-main {
  margin-bottom: 1.25rem;
}

.project-header-text h3 {
  font-size: 1.5rem;
  margin-top: 0.5rem;
  margin-bottom: 0.4rem;
}

.project-meta-line {
  font-size: 0.9rem;
  color: var(--text-light);
  margin-bottom: 0;
}

.tech-tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1.25rem;
}

/* 10. Clients Grid */
.clients-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 1.25rem;
  align-items: center;
}

.client-card {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.25rem;
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  min-height: 90px;
  text-decoration: none;
  transition: border-color 0.15s ease;
}

.client-card:hover {
  border-color: var(--text-light);
}

.client-logo {
  max-width: 100%;
  max-height: 50px;
  object-fit: contain;
  filter: grayscale(100%);
  opacity: 0.75;
  transition: filter 0.15s ease, opacity 0.15s ease;
}

.client-card:hover .client-logo {
  filter: grayscale(0%);
  opacity: 1;
}

.client-name {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--text-muted);
}

/* 11. Articles & Blog Lists */
.articles-list, .blog-articles-list {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.article-item, .blog-list-item {
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--border-color);
}

.article-item:last-child, .blog-list-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-light);
  font-family: var(--font-mono);
  margin-bottom: 0.5rem;
}

.meta-dot {
  color: var(--border-dark);
}

.article-title, .blog-item-title {
  font-size: 1.4rem;
  margin-top: 0;
  margin-bottom: 0.65rem;
}

.article-title a, .blog-item-title a {
  color: var(--text-main);
  text-decoration: none;
}

.article-title a:hover, .blog-item-title a:hover {
  color: var(--accent-color);
}

.article-summary, .blog-item-summary {
  color: var(--text-muted);
  font-size: 1rem;
  margin-bottom: 0.75rem;
  line-height: 1.6;
}

.article-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 0.75rem;
}

.article-read-more, .read-more-link {
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
}

/* 12. Contact & Careers Merged Layout */
.contact-careers-grid {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

.contact-details-card {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.contact-item strong {
  display: block;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-light);
  margin-bottom: 0.35rem;
}

.contact-item p {
  margin-bottom: 0;
  font-size: 1rem;
}

.map-container {
  margin-top: 1.5rem;
}

.map-container h3 {
  margin-top: 0;
  margin-bottom: 1rem;
}

.apply-box {
  background-color: var(--bg-alt);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  margin-top: 1.5rem;
}

.apply-box p {
  margin-bottom: 0.5rem;
}

.apply-box ul {
  margin-bottom: 0;
}

/* 13. Single Post & Markdown Prose Styling */
.single-post-container {
  max-width: 820px;
  margin: 0 auto;
}

.post-header {
  margin-bottom: 2.5rem;
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--border-color);
}

.back-link {
  display: inline-block;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-light);
  text-decoration: none;
  margin-bottom: 1.25rem;
}

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

.post-title {
  font-size: 2.25rem;
  line-height: 1.25;
  margin-bottom: 1rem;
  letter-spacing: -0.03em;
}

.post-lead {
  font-size: 1.2rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-top: 0.75rem;
}

.post-tags {
  margin-top: 0.75rem;
}

.prose {
  color: var(--text-main);
  font-size: 1.05rem;
  line-height: 1.75;
}

.prose h2 {
  font-size: 1.6rem;
  margin-top: 2.25rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.4rem;
}

.prose h3 {
  font-size: 1.3rem;
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
}

.prose ul, .prose ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.prose li {
  margin-bottom: 0.5rem;
}

.prose blockquote {
  border-left: 4px solid var(--accent-color);
  padding-left: 1.25rem;
  margin: 1.75rem 0;
  color: var(--text-muted);
  font-style: italic;
}

.prose code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background-color: var(--code-bg);
  padding: 0.2em 0.4em;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

.prose pre {
  background-color: var(--code-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  overflow-x: auto;
  margin: 1.75rem 0;
}

.prose pre code {
  background-color: transparent;
  border: none;
  padding: 0;
  font-size: 0.9em;
}

.prose img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  margin: 1.75rem 0;
}

.post-footer {
  margin-top: 3.5rem;
  padding-top: 1.75rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* 14. Site Footer */
.site-footer {
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-alt);
  padding: 3.5rem 0 2rem;
  margin-top: auto;
}

.site-footer-inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 2.5rem;
}

@media (max-width: 768px) {
  .site-footer-inner {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

.footer-brand-title {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-main);
  text-decoration: none;
  display: inline-block;
  margin-bottom: 0.5rem;
}

.footer-brand-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  max-width: 380px;
  line-height: 1.5;
  margin-bottom: 1rem;
}

.footer-contact-info {
  font-size: 0.9rem;
  color: var(--text-muted);
}

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

.footer-heading {
  font-size: 0.95rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-main);
  margin-top: 0;
  margin-bottom: 1rem;
}

.footer-menu {
  list-style: none;
}

.footer-menu li {
  margin-bottom: 0.5rem;
}

.footer-menu a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
}

.footer-menu a:hover {
  color: var(--text-main);
}

.footer-social-links {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 1rem;
}

.social-link {
  font-size: 0.85rem;
  color: var(--text-muted);
  text-decoration: none;
}

.social-link:hover {
  color: var(--text-main);
}

.social-sep {
  color: var(--border-dark);
  font-size: 0.75rem;
}

.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding-top: 1.5rem;
  font-size: 0.85rem;
  color: var(--text-light);
  text-align: center;
}