/* ============================================================
   PortDesignLab — styles.css
   ============================================================ */

/* --- Variables --- */
:root {
  --red:          #C8201A;
  --red-soft:     rgba(200, 32, 26, 0.12);
  --red-faint:    rgba(200, 32, 26, 0.06);
  --red-border:   rgba(200, 32, 26, 0.12);
  --red-border-light: rgba(200, 32, 26, 0.10);

  --text-primary:   #111111;
  --text-secondary: #666666;
  --text-muted:     #777777;
  --text-dim:       #999999;
  --bg:             #ffffff;

  --font-display: 'DM Sans', sans-serif;
  --font-mono:    'Space Mono', monospace;

  --pad-h: 36px;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text-primary);
  font-family: var(--font-display);
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

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

/* --- Page wrapper --- */
.page {
  position: relative;
  overflow: hidden;
  min-height: 100vh;
}

/* --- Grid background --- */
.grid-bg::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--red-faint) 1px, transparent 1px),
    linear-gradient(90deg, var(--red-faint) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
  z-index: 0;
}
.grid-bg > * { position: relative; z-index: 1; }

/* --- Corner marks --- */
.corner-mark {
  position: absolute;
  width: 52px;
  height: 52px;
  opacity: 0.25;
  pointer-events: none;
  z-index: 2;
}
.corner-mark.tl { top: 18px; left: 18px; border-top: 1px solid var(--red); border-left: 1px solid var(--red); }
.corner-mark.tr { top: 18px; right: 18px; border-top: 1px solid var(--red); border-right: 1px solid var(--red); }

/* ============================================================
   NAVIGATION
   ============================================================ */
.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 var(--pad-h);
  height: 52px;
  border-bottom: 3px solid var(--red);
  background: var(--bg);
  position: relative;
  z-index: 100;
}

.nav-logo {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--red);
  letter-spacing: 0.15em;
  text-transform: uppercase;
}
.nav-logo span { color: var(--text-primary); }

.nav-links {
  display: flex;
  gap: 22px;
  align-items: center;
}
.nav-links a {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--text-secondary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--red); }

.nav-lang {
  background: var(--red);
  color: #fff;
  font-family: var(--font-mono);
  font-size: 16px;
  padding: 5px 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  border: none;
  cursor: pointer;
  transition: opacity 0.2s;
}
.nav-lang:hover { opacity: 0.85; }

.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 4px;
}
.nav-hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  transition: transform 0.2s, opacity 0.2s;
}

/* Hamburger open state */
.nav-hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* --- Mobile menu --- */
.mobile-menu {
  display: none;
  flex-direction: column;
  gap: 0;
  background: var(--bg);
  border-bottom: 1px solid var(--red-border);
  position: relative;
  z-index: 99;
}
.mobile-menu.open { display: flex; }
.mobile-menu a,
.mobile-menu button {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--text-secondary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 14px var(--pad-h);
  border-bottom: 1px solid var(--red-border-light);
  display: block;
  background: none;
  border-left: none;
  border-right: none;
  border-top: none;
  cursor: pointer;
  text-align: left;
}
.mobile-menu a:hover,
.mobile-menu button:hover { color: var(--red); }

.mobile-lang-form {
  display: flex;
  gap: 0;
  padding: 14px var(--pad-h);
  border-bottom: 1px solid var(--red-border-light);
  margin: 0;
}
.mobile-lang-form button {
  font-family: var(--font-mono);
  font-size: 16px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
  background: none;
  border: none;
  padding: 0 20px 0 0;
  cursor: pointer;
  display: inline;
  text-align: left;
}
.mobile-lang-form button.lang-active { color: var(--red); font-weight: 700; }
.mobile-lang-form button:hover { color: var(--red); }

/* ============================================================
   HERO
   ============================================================ */
.hero {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-bottom: 1px solid var(--red-border);
}

.hero-left {
  padding: 56px var(--pad-h) 40px;
  border-right: 1px solid var(--red-border);
}

.hero-right {
  padding: 40px 40px 40px 64px;
  display: flex;
  flex-direction: column;
}

.hero-tag {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--red);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  margin-bottom: 20px;
}

.hero-title {
  font-family: var(--font-display);
  font-size: 56px;
  font-weight: 900;
  line-height: 1.0;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  margin-bottom: 18px;
}
.hero-title span { color: var(--red); }

.hero-sub {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: 36px;
}

.hero-actions {
  display: flex;
  gap: 12px;
  align-items: center;
  flex-wrap: wrap;
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn-primary {
  background: var(--red);
  color: #fff;
  padding: 11px 26px;
  font-family: var(--font-mono);
  font-size: 16px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  border: none;
  cursor: pointer;
  font-weight: 700;
  display: inline-block;
  transition: opacity 0.2s;
}
.btn-primary:hover { opacity: 0.88; }

.btn-ghost {
  background: transparent;
  color: var(--red);
  padding: 11px 26px;
  font-family: var(--font-mono);
  font-size: 16px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  border: 1px solid rgba(200, 32, 26, 0.35);
  cursor: pointer;
  display: inline-block;
  transition: background 0.2s, border-color 0.2s;
}
.btn-ghost:hover {
  border-color: var(--red);
  background: rgba(200, 32, 26, 0.04);
}

/* ============================================================
   BLOG (in hero-right)
   ============================================================ */
.blog-header {
  font-family: var(--font-mono);
  font-size: 16px;
  color: rgba(200, 32, 26, 0.5);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-bottom: 16px;
}

.blog-item {
  padding: 16px 0;
  border-bottom: 1px solid var(--red-border-light);
  cursor: pointer;
  display: flex;
  gap: 14px;
  align-items: flex-start;
  text-decoration: none;
  color: inherit;
}
.blog-item:first-of-type { border-top: 1px solid var(--red-border-light); }
.blog-item:hover .blog-title { color: var(--red); }

.blog-date {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--text-dim);
  letter-spacing: 0.08em;
  min-width: 88px;
  padding-top: 2px;
  flex-shrink: 0;
}

.blog-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.35;
  margin-bottom: 4px;
  transition: color 0.15s;
}

.blog-excerpt {
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.6;
}

.blog-more {
  margin-top: 20px;
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--red);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  text-decoration: none;
  transition: opacity 0.2s;
}
.blog-more:hover { opacity: 0.7; }

/* ============================================================
   TOOLS GRID
   ============================================================ */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--red-soft);
  margin: 0 var(--pad-h) var(--pad-h);
  border: 0.5px solid var(--red-border);
}

.tool-card {
  background: var(--bg);
  padding: 22px 20px 32px;
  cursor: pointer;
  transition: background 0.15s;
  position: relative;
  overflow: hidden;
  display: block;
  color: inherit;
  text-decoration: none;
}
.tool-card::after {
  content: '';
  position: absolute;
  left: 0; top: 0;
  width: 3px;
  height: 100%;
  background: var(--red);
  transform: scaleY(0);
  transition: transform 0.2s;
  transform-origin: bottom;
}
.tool-card:hover { background: #fef7f7; }
.tool-card:hover::after { transform: scaleY(1); }
.tool-card:hover .tool-arrow { opacity: 1; }

.tool-card--empty {
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: default;
}
.tool-card--empty::after { display: none; }
.tool-card--empty:hover { background: var(--bg); }

.tool-num {
  font-family: var(--font-mono);
  font-size: 16px;
  color: rgba(200, 32, 26, 0.5);
  letter-spacing: 0.12em;
  margin-bottom: 12px;
}

.tool-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.tool-desc {
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.6;
}

.tool-arrow {
  position: absolute;
  bottom: 14px;
  right: 16px;
  color: var(--red);
  font-size: 18px;
  opacity: 0;
  transition: opacity 0.15s;
}

.tool-coming {
  font-family: var(--font-mono);
  font-size: 16px;
  color: rgba(200, 32, 26, 0.3);
  letter-spacing: 0.15em;
  text-align: center;
  line-height: 1.8;
  text-transform: uppercase;
}

/* ============================================================
   STATUS BAR
   ============================================================ */
.status-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px var(--pad-h);
  border-top: 0.5px solid var(--red-border-light);
}

.status-dot {
  width: 6px;
  height: 6px;
  background: var(--red);
  border-radius: 50%;
  flex-shrink: 0;
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0.2; }
}

.status-txt {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--text-dim);
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

/* ============================================================
   RESPONSIVE
   ============================================================ */

/* Tablet landscape: ≤ 1024px */
@media (max-width: 1024px) {
  :root { --pad-h: 24px; }
  .hero-title { font-size: 42px; }
}

/* Tablet portrait: ≤ 768px */
@media (max-width: 768px) {
  :root { --pad-h: 20px; }

  .nav-links { display: none; }
  .nav-hamburger { display: flex; }
  .corner-mark { display: none; }

  .hero { grid-template-columns: 1fr; }
  .hero-left {
    border-right: none;
    border-bottom: 1px solid var(--red-border);
    padding-top: 36px;
    padding-bottom: 28px;
  }
  .hero-right { padding-top: 28px; }
  .hero-title { font-size: 44px; }

  .blog-date { display: none; }

  .tools-grid { grid-template-columns: repeat(2, 1fr); }
  .tool-card--empty { display: none; }
}

/* Small tablet: ≤ 600px */
@media (max-width: 600px) {
  :root { --pad-h: 16px; }

  .hero-title { font-size: 36px; }

  .btn-primary,
  .btn-ghost { padding: 10px 18px; }
}


/* ============================================================
   BLOG POST PAGE
   ============================================================ */

.article-wrap {
  display: grid;
  grid-template-columns: 1fr min(720px, 100%) 1fr;
  padding: 48px 0 64px;
}
.article-wrap > * { grid-column: 2; min-width: 0; }

/* Article header */
.article-header {
  margin-bottom: 40px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--red-border);
}
.article-back {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--red);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 20px;
  text-decoration: none;
  transition: opacity 0.2s;
}
.article-back:hover { opacity: 0.7; }

.article-date {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--text-dim);
  letter-spacing: 0.1em;
  margin-bottom: 12px;
}
.article-title {
  font-family: var(--font-display);
  font-size: 36px;
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

/* Body text */
.article-body {
  overflow-wrap: break-word;
  word-break: break-word;
  min-width: 0;
}

.article-body p {
  font-family: var(--font-display);
  font-size: 16px;
  line-height: 1.8;
  color: #333;
  margin-bottom: 20px;
}
.article-body h2 {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 700;
  color: var(--text-primary);
  margin: 40px 0 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--red);
  letter-spacing: -0.01em;
}
.article-body h3 {
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 700;
  color: var(--text-primary);
  margin: 28px 0 12px;
}
.article-body strong {
  font-weight: 700;
  color: var(--text-primary);
}
.article-body ul,
.article-body ol {
  font-size: 16px;
  line-height: 1.8;
  color: #333;
  margin: 0 0 20px 24px;
}
.article-body li { margin-bottom: 6px; }

/* Figures */
.article-body figure {
  margin: 32px 0;
  text-align: center;
}
.article-body figure img {
  max-width: 100%;
  height: auto;
  border: 0.5px solid var(--red-border);
}
.article-body figcaption {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  margin-top: 10px;
  text-align: center;
}

/* Tables */
.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 28px 0;
  font-size: 16px;
  display: block;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.article-body thead tr {
  border-bottom: 2px solid var(--red);
}
.article-body th {
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  color: var(--red);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 10px 12px;
  text-align: left;
}
.article-body td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--red-border-light);
  color: #333;
  line-height: 1.5;
}
.article-body tr:last-child td { border-bottom: none; }

/* Math formula blocks */
.article-body .math-block {
  font-family: var(--font-mono);
  font-size: 16px;
  background: rgba(200, 32, 26, 0.04);
  border-left: 3px solid var(--red);
  padding: 16px 20px;
  margin: 24px 0;
  overflow-x: auto;
  color: var(--text-primary);
}

/* Inline code */
.article-body code {
  font-family: var(--font-mono);
  font-size: 16px;
  background: rgba(200, 32, 26, 0.06);
  color: var(--red);
  padding: 2px 6px;
}

/* References */
.article-references {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--red-border);
}
.article-references h2 {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--red);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-bottom: 16px;
  border: none;
  padding: 0;
}
.article-references ol {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.8;
  margin-left: 20px;
}
.article-references a {
  color: var(--red);
  word-break: break-all;
}

/* Blog list page */
.blog-list {
  padding: 48px var(--pad-h) 64px;
}
.blog-list-header {
  margin-bottom: 32px;
  padding-bottom: 20px;
  border-bottom: 3px solid var(--red);
}
.blog-list-title {
  font-family: var(--font-display);
  font-size: 36px;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}
.blog-list-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--red-soft);
  border: 0.5px solid var(--red-border);
}
.blog-list-card {
  background: var(--bg);
  padding: 24px 20px 28px;
  display: block;
  text-decoration: none;
  color: inherit;
  cursor: pointer;
  transition: background 0.15s;
  position: relative;
  overflow: hidden;
}
.blog-list-card::after {
  content: '';
  position: absolute;
  left: 0; top: 0;
  width: 3px; height: 100%;
  background: var(--red);
  transform: scaleY(0);
  transition: transform 0.2s;
  transform-origin: bottom;
}
.blog-list-card:hover { background: #fef7f7; }
.blog-list-card:hover::after { transform: scaleY(1); }
.blog-list-card:hover .blog-list-card-title { color: var(--red); }
.blog-list-card-date {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--red);
  opacity: 0.6;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 10px;
}
.blog-list-card-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.35;
  margin-bottom: 10px;
  transition: color 0.15s;
}
.blog-list-card-excerpt {
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ============================================================
   BLOG RESPONSIVE
   ============================================================ */
@media (max-width: 1024px) {
  .blog-list-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .article-wrap {
    grid-template-columns: 1fr;
    padding: 28px var(--pad-h) 48px;
  }
  .article-wrap > * { grid-column: 1; }
  .article-title { font-size: 28px; }
  .article-body h2 { font-size: 20px; }
  .article-body p,
  .article-body ul,
  .article-body ol { font-size: 16px; }
  .blog-list-grid { grid-template-columns: 1fr; }
  .blog-list { padding-top: 32px; }
}

@media (max-width: 600px) {
  .article-title { font-size: 24px; }
}

/* ============================================================
   TOOL PAGES
   ============================================================ */
.tool-page {
  padding: 48px var(--pad-h) 72px;
}

.tool-page-tag {
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--red);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.tool-page-title {
  font-family: var(--font-display);
  font-size: 32px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 32px;
  line-height: 1.2;
}

.tool-page h5 {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 600;
  color: var(--text-primary);
  margin: 24px 0 16px;
}

.tool-page .table {
  color: var(--text-primary);
}

.tool-page .table > :not(caption) > * > * {
  border-color: rgba(0, 0, 0, 0.08);
}

.tool-page .table thead th,
.tool-page .table > thead > tr > th {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-secondary);
}

.tool-page .form-control,
.tool-page .form-select {
  border-color: rgba(0, 0, 0, 0.15);
  color: var(--text-primary);
  font-family: var(--font-display);
}

.tool-page .form-control:focus,
.tool-page .form-select:focus {
  border-color: var(--red);
  box-shadow: 0 0 0 2px var(--red-soft);
}

.tool-page .btn-danger {
  background-color: var(--red);
  border-color: var(--red);
  font-family: var(--font-mono);
  font-size: 16px;
  letter-spacing: 0.06em;
}

.tool-page .btn-danger:hover,
.tool-page .btn-danger:active {
  background-color: #a51915;
  border-color: #a51915;
}

.tool-page-header {
  padding: 16px var(--pad-h) 4px;
}

@media (max-width: 768px) {
  .tool-page { padding: 28px var(--pad-h) 48px; }
  .tool-page-title { font-size: 24px; }
}