/* ============================================================
   Portfolio — Cybersecurity × AI × Systems
   Phong cách: academic / minimal + technical density
   ============================================================ */

/* ---------- CSS VARIABLES: Light (default) ---------- */
:root {
  --font: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas,
    monospace;

  --sidebar-width: 280px;
  --content-max: 720px;
  --content-wide: 920px;
  --radius: 10px;
  --transition: 0.2s ease;

  /* Light palette */
  --bg: #fafafa;
  --bg-elevated: #ffffff;
  --sidebar-bg: #f3f4f6;
  --text: #1f2937;
  --text-muted: #6b7280;
  --heading: #111827;
  --border: #e5e7eb;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-soft: rgba(37, 99, 235, 0.08);
  --tag-bg: #eef2ff;
  --tag-text: #3730a3;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --overlay: rgba(17, 24, 39, 0.4);
  --mobile-header-h: 56px;
}

/* ---------- Dark mode ---------- */
[data-theme="dark"] {
  --bg: #0f1115;
  --bg-elevated: #171a21;
  --sidebar-bg: #12151b;
  --text: #e5e7eb;
  --text-muted: #9ca3af;
  --heading: #f9fafb;
  --border: #2a2f3a;
  --accent: #60a5fa;
  --accent-hover: #93c5fd;
  --accent-soft: rgba(96, 165, 250, 0.12);
  --tag-bg: #1e293b;
  --tag-text: #93c5fd;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.35);
  --overlay: rgba(0, 0, 0, 0.55);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 1.5rem;
}

body {
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  display: block;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition);
}

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

/* ---------- Mobile header ---------- */
.mobile-header {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--mobile-header-h);
  z-index: 100;
  background: var(--sidebar-bg);
  border-bottom: 1px solid var(--border);
  align-items: center;
  justify-content: space-between;
  padding: 0 1rem;
}

.mobile-title {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--heading);
}

/* Hamburger */
.menu-toggle {
  width: 40px;
  height: 40px;
  border: none;
  background: transparent;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  color: var(--heading);
}

.menu-toggle:hover {
  background: var(--accent-soft);
}

.hamburger,
.hamburger::before,
.hamburger::after {
  display: block;
  width: 20px;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  position: relative;
  transition: transform var(--transition), opacity var(--transition);
}

.hamburger::before,
.hamburger::after {
  content: "";
  position: absolute;
  left: 0;
}

.hamburger::before {
  top: -6px;
}

.hamburger::after {
  top: 6px;
}

body.nav-open .hamburger {
  background: transparent;
}

body.nav-open .hamburger::before {
  top: 0;
  transform: rotate(45deg);
}

body.nav-open .hamburger::after {
  top: 0;
  transform: rotate(-45deg);
}

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: var(--overlay);
  z-index: 90;
  opacity: 0;
  transition: opacity var(--transition);
}

body.nav-open .sidebar-overlay {
  display: block;
  opacity: 1;
}

/* ---------- Sidebar ---------- */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  z-index: 95;
  transition: transform var(--transition), background var(--transition);
}

.sidebar-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 2.25rem 1.5rem 2rem;
  text-align: center;
  min-height: 100%;
}

.avatar-wrap {
  margin-bottom: 1.25rem;
}

.avatar {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--border);
  background: var(--bg-elevated);
  box-shadow: var(--shadow);
}

.sidebar-name {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--heading);
  letter-spacing: -0.02em;
  line-height: 1.3;
  margin-bottom: 0.25rem;
}

.sidebar-title {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--accent);
  margin-bottom: 1rem;
}

.sidebar-bio {
  font-size: 0.8125rem;
  color: var(--text-muted);
  line-height: 1.55;
  margin-bottom: 1.5rem;
}

/* Nav links */
.sidebar-nav {
  display: flex;
  flex-direction: column;
  width: 100%;
  gap: 0.15rem;
  margin-bottom: 1.75rem;
}

.nav-link {
  display: block;
  padding: 0.5rem 0.75rem;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  transition: background var(--transition), color var(--transition);
}

.nav-link:hover {
  background: var(--accent-soft);
  color: var(--accent);
  text-decoration: none;
}

.nav-link.active {
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 600;
}

/* Social */
.social-links {
  display: flex;
  gap: 0.65rem;
  margin-bottom: 1.5rem;
}

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  color: var(--text-muted);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  transition: color var(--transition), border-color var(--transition),
    background var(--transition), transform var(--transition);
}

.social-links a:hover {
  color: var(--accent);
  border-color: var(--accent);
  text-decoration: none;
  transform: translateY(-2px);
}

/* Theme toggle button */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.9rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text);
  font-family: inherit;
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition),
    color var(--transition);
}

.theme-toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.theme-icon {
  display: inline-flex;
  width: 1rem;
  height: 1rem;
}

.theme-icon svg {
  width: 100%;
  height: 100%;
}

.mobile-theme {
  width: 40px;
  height: 40px;
  padding: 0;
  justify-content: center;
  border-radius: 8px;
}

.mobile-theme .theme-label {
  display: none;
}

/* ---------- Main content ---------- */
.main-content {
  margin-left: var(--sidebar-width);
  min-height: 100vh;
  padding: 3rem 2.5rem 4rem;
}

.section {
  max-width: var(--content-max);
  margin: 0 auto 3.5rem;
  scroll-margin-top: 1.5rem;
}

.section:last-of-type {
  margin-bottom: 2rem;
}

.section-title {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--heading);
  letter-spacing: -0.03em;
  margin-bottom: 1.25rem;
  padding-bottom: 0.65rem;
  border-bottom: 2px solid var(--border);
}

.subsection-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--heading);
  margin: 1.5rem 0 0.75rem;
}

.section-body p {
  margin-bottom: 1rem;
  color: var(--text);
}

.section-intro {
  color: var(--text-muted) !important;
  margin-bottom: 1.5rem !important;
}

.bullet-list {
  margin: 0.5rem 0 0 1.25rem;
  color: var(--text);
}

.bullet-list li {
  margin-bottom: 0.4rem;
}

/* ---------- Skills ---------- */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1rem;
}

.skill-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.15rem 1.2rem;
  box-shadow: var(--shadow);
  transition: box-shadow var(--transition), border-color var(--transition);
}

.skill-card:hover {
  box-shadow: var(--shadow-md);
  border-color: color-mix(in srgb, var(--accent) 35%, var(--border));
}

.skill-card-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--heading);
  margin-bottom: 0.75rem;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 500;
  padding: 0.28rem 0.6rem;
  border-radius: 999px;
  background: var(--tag-bg);
  color: var(--tag-text);
  line-height: 1.3;
}

.tag-sm {
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
}

/* ---------- Certifications ---------- */
.cert-list {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.cert-card {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem 1.2rem;
  box-shadow: var(--shadow);
  transition: box-shadow var(--transition);
}

.cert-card:hover {
  box-shadow: var(--shadow-md);
}

.cert-planned {
  opacity: 0.92;
}

.cert-badge {
  flex-shrink: 0;
  width: 52px;
  height: 52px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.7rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  line-height: 1.15;
  border: 1px solid color-mix(in srgb, var(--accent) 25%, var(--border));
}

.cert-name {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--heading);
  margin-bottom: 0.2rem;
}

.cert-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.35rem !important;
}

.cert-desc {
  font-size: 0.875rem;
  color: var(--text);
  margin-bottom: 0.35rem !important;
}

.cert-link {
  font-size: 0.85rem;
  font-weight: 500;
}

.status-badge {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0.1rem 0.45rem;
  border-radius: 4px;
  background: var(--accent-soft);
  color: var(--accent);
  vertical-align: middle;
}

/* ---------- Write-ups (legacy list + blog cards) ---------- */
.post-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.post-card {
  padding: 1.35rem 0;
  border-bottom: 1px solid var(--border);
}

.post-card:first-child {
  padding-top: 0;
}

.post-date {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
  font-variant-numeric: tabular-nums;
}

.post-title {
  font-size: 1.1rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 0.45rem;
}

.post-title a {
  color: var(--heading);
  text-decoration: none;
}

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

.post-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 0.65rem !important;
}

.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

/* Wider section for blog grids / featured content */
.section-wide {
  max-width: min(var(--content-wide), 100%);
}

.site-footer {
  max-width: min(var(--content-wide), 100%);
}

.nav-link-sub {
  font-size: 0.8rem !important;
  opacity: 0.9;
  margin-top: -0.1rem;
}

/* Filter chips */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-bottom: 0.75rem;
}

.filter-btn {
  font-family: inherit;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.4rem 0.85rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text-muted);
  cursor: pointer;
  transition: background var(--transition), color var(--transition),
    border-color var(--transition), box-shadow var(--transition);
}

.filter-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.filter-btn.is-active {
  background: var(--accent-soft);
  border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
  color: var(--accent);
  box-shadow: var(--shadow);
}

.filter-btn .filter-count {
  font-weight: 500;
  opacity: 0.75;
  margin-left: 0.2rem;
}

.filter-status {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 1rem !important;
  min-height: 1.2em;
}

/* Blog card grid */
.blog-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
}

.blog-card {
  display: flex;
  flex-direction: column;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.15rem 1.2rem;
  box-shadow: var(--shadow);
  text-decoration: none;
  color: inherit;
  transition: box-shadow var(--transition), transform var(--transition),
    border-color var(--transition);
  min-height: 100%;
}

.blog-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: color-mix(in srgb, var(--accent) 35%, var(--border));
  text-decoration: none;
  color: inherit;
}

.blog-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.65rem;
}

.blog-card-icon {
  font-size: 1.35rem;
  line-height: 1;
}

.blog-card-title {
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--heading);
  line-height: 1.35;
  margin-bottom: 0.45rem;
}

.blog-card:hover .blog-card-title {
  color: var(--accent);
}

.blog-card-excerpt {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.55;
  flex: 1;
  margin-bottom: 0.75rem !important;
}

.blog-card-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem 0.65rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: auto;
  padding-top: 0.5rem;
  border-top: 1px solid var(--border);
}

.blog-card-meta time {
  font-variant-numeric: tabular-nums;
}

.blog-empty {
  text-align: center;
  color: var(--text-muted);
  padding: 2rem 1rem;
  font-size: 0.9rem;
}

.blog-hub-link {
  margin-top: 1.5rem !important;
  text-align: center;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-soft);
  border: 1px solid color-mix(in srgb, var(--accent) 30%, var(--border));
  border-radius: 8px;
  padding: 0.55rem 1.1rem;
  text-decoration: none;
  transition: background var(--transition), border-color var(--transition);
}

.btn-secondary:hover {
  background: color-mix(in srgb, var(--accent) 18%, var(--bg-elevated));
  text-decoration: none;
  color: var(--accent-hover);
}

/* Category / difficulty badges */
.cat-badge,
.diff-badge {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  padding: 0.2rem 0.5rem;
  border-radius: 6px;
  line-height: 1.2;
}

.cat-soc {
  background: rgba(16, 185, 129, 0.12);
  color: #059669;
}
.cat-htb {
  background: rgba(245, 158, 11, 0.14);
  color: #d97706;
}
.cat-tryhackme {
  background: rgba(168, 85, 247, 0.12);
  color: #7c3aed;
}
.cat-ad {
  background: rgba(239, 68, 68, 0.12);
  color: #dc2626;
}
.cat-footprinting {
  background: rgba(59, 130, 246, 0.12);
  color: #2563eb;
}

[data-theme="dark"] .cat-soc {
  color: #34d399;
}
[data-theme="dark"] .cat-htb {
  color: #fbbf24;
}
[data-theme="dark"] .cat-tryhackme {
  color: #c4b5fd;
}
[data-theme="dark"] .cat-ad {
  color: #f87171;
}
[data-theme="dark"] .cat-footprinting {
  color: #60a5fa;
}

.diff-easy {
  background: var(--accent-soft);
  color: var(--accent);
}
.diff-medium {
  background: rgba(245, 158, 11, 0.12);
  color: #d97706;
}
.diff-hard,
.diff-insane {
  background: rgba(239, 68, 68, 0.12);
  color: #dc2626;
}
.diff-notes {
  background: var(--tag-bg);
  color: var(--tag-text);
}

[data-theme="dark"] .diff-medium {
  color: #fbbf24;
}
[data-theme="dark"] .diff-hard,
[data-theme="dark"] .diff-insane {
  color: #f87171;
}

/* Sidebar category list (blog pages) */
.blog-side-cats {
  width: 100%;
  text-align: left;
  margin-bottom: 1.5rem;
  padding: 0.75rem 0.5rem;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.blog-side-cats-title {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
  padding: 0 0.35rem;
}

.blog-side-cats a {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 0.35rem 0.5rem;
  border-radius: 6px;
  text-decoration: none;
  transition: background var(--transition), color var(--transition);
}

.blog-side-cats a:hover,
.blog-side-cats a.is-active {
  background: var(--accent-soft);
  color: var(--accent);
  text-decoration: none;
}

/* ---------- Write-up detail pages ---------- */
.writeup-main {
  padding-top: 2.5rem;
}

.writeup-article {
  max-width: 780px;
  margin: 0 auto 3rem;
}

.writeup-back {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
  text-decoration: none;
}

.writeup-back:hover {
  text-decoration: underline;
}

.writeup-header {
  margin-bottom: 1.75rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
}

.writeup-meta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 0.75rem;
  margin-bottom: 0.75rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.writeup-title {
  font-size: 1.85rem;
  font-weight: 700;
  color: var(--heading);
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin-bottom: 0.65rem;
}

.writeup-lead {
  font-size: 1.02rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 0.85rem !important;
}

.writeup-tags {
  margin-top: 0.25rem;
}

.writeup-toc {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow);
}

.writeup-toc-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.writeup-toc ol {
  margin: 0 0 0 1.1rem;
  font-size: 0.9rem;
}

.writeup-toc li {
  margin-bottom: 0.3rem;
}

.writeup-section {
  margin-bottom: 2.25rem;
  scroll-margin-top: 1.5rem;
}

.writeup-section h2 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--heading);
  margin-bottom: 0.85rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
}

.writeup-section h3 {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--heading);
  margin: 1.25rem 0 0.5rem;
}

.writeup-section p,
.writeup-section li {
  color: var(--text);
}

.writeup-section ul,
.writeup-section ol:not(.numbered-steps) {
  margin: 0.5rem 0 0.75rem 1.25rem;
}

.writeup-section li {
  margin-bottom: 0.35rem;
}

.numbered-steps {
  margin: 0.5rem 0 0.75rem 1.25rem;
  counter-reset: step;
  list-style: decimal;
}

.numbered-steps li {
  margin-bottom: 0.55rem;
}

.checklist {
  list-style: none;
  margin-left: 0 !important;
}

.checklist li {
  padding-left: 0.25rem;
}

.table-wrap {
  overflow-x: auto;
  margin: 0.75rem 0 1rem;
  border-radius: 8px;
  border: 1px solid var(--border);
}

.writeup-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
  background: var(--bg-elevated);
}

.writeup-table th,
.writeup-table td {
  padding: 0.65rem 0.85rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

.writeup-table th {
  width: 32%;
  font-weight: 600;
  color: var(--heading);
  background: color-mix(in srgb, var(--sidebar-bg) 80%, var(--bg-elevated));
}

.writeup-table tr:last-child th,
.writeup-table tr:last-child td {
  border-bottom: none;
}

.writeup-table thead th {
  width: auto;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.code-block {
  margin: 0.75rem 0 1rem;
  padding: 1rem 1.1rem;
  background: #0f172a;
  color: #e2e8f0;
  border-radius: 8px;
  overflow-x: auto;
  font-size: 0.8rem;
  line-height: 1.55;
  border: 1px solid #1e293b;
}

[data-theme="light"] .code-block {
  background: #1e293b;
}

.code-block code {
  font-family: ui-monospace, "Cascadia Code", "Source Code Pro", Menlo, Consolas,
    monospace;
  white-space: pre;
}

.writeup-figure {
  margin: 1rem 0 1.25rem;
}

.img-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 160px;
  padding: 1.5rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  background: repeating-linear-gradient(
    -45deg,
    var(--bg-elevated),
    var(--bg-elevated) 10px,
    var(--sidebar-bg) 10px,
    var(--sidebar-bg) 20px
  );
  border: 2px dashed var(--border);
  border-radius: var(--radius);
}

.img-placeholder code {
  font-size: 0.72rem;
  word-break: break-all;
  opacity: 0.85;
}

.writeup-figure figcaption {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
  margin-top: 0.5rem;
  font-style: italic;
}

.callout {
  border-radius: 8px;
  padding: 0.85rem 1rem;
  margin: 1rem 0;
  font-size: 0.9rem;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
}

.callout-info {
  border-color: color-mix(in srgb, var(--accent) 35%, var(--border));
  background: var(--accent-soft);
}

.callout-warn {
  border-color: color-mix(in srgb, #f59e0b 40%, var(--border));
  background: rgba(245, 158, 11, 0.1);
}

.attack-path {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.35rem 0.5rem;
  margin: 1rem 0;
  padding: 0.75rem 1rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--heading);
}

.ap-arrow {
  color: var(--text-muted);
  font-weight: 400;
}

.writeup-footer {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}

.writeup-disclaimer {
  font-size: 0.8rem !important;
  color: var(--text-muted) !important;
  margin-top: 0.75rem !important;
}

.blog-how-to {
  margin-bottom: 1.25rem;
}

.blog-how-to code {
  font-size: 0.8em;
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
  background: var(--bg);
  border: 1px solid var(--border);
}

@media (max-width: 900px) {
  .writeup-section {
    scroll-margin-top: calc(var(--mobile-header-h) + 1rem);
  }

  .writeup-title {
    font-size: 1.45rem;
  }
}

@media (max-width: 480px) {
  .blog-card-grid {
    grid-template-columns: 1fr;
  }
}

/* ---------- Hero / identity ---------- */
.hero-block {
  margin-bottom: 2.5rem;
  padding: 1.5rem 1.35rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: calc(var(--radius) + 2px);
  box-shadow: var(--shadow);
  border-left: 3px solid var(--accent);
}

.hero-kicker {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.65rem !important;
  font-family: var(--font-mono);
}

.hero-title {
  font-size: clamp(1.35rem, 2.5vw, 1.75rem);
  font-weight: 700;
  color: var(--heading);
  letter-spacing: -0.03em;
  line-height: 1.3;
  margin-bottom: 0.85rem;
}

.hero-lead {
  font-size: 1rem;
  color: var(--text-muted);
  margin-bottom: 1.15rem !important;
  max-width: 52rem;
}

.hero-pillars {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem;
}

.pillar-chip {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid color-mix(in srgb, var(--accent) 28%, var(--border));
}

.pillar-chip-plus {
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 0 0.15rem;
  font-weight: 500;
}

.sidebar-tagline {
  font-size: 0.75rem;
  color: var(--text-muted);
  line-height: 1.4;
  margin: -0.35rem 0 0.85rem;
  max-width: 16rem;
}

.identity-quote {
  margin: 1.5rem 0;
  padding: 1rem 1.15rem;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.identity-quote p {
  margin-bottom: 0.35rem !important;
  color: var(--heading);
  font-family: var(--font-mono);
  font-size: 0.92rem;
}

.identity-quote footer {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.callout-accent {
  border-color: color-mix(in srgb, var(--accent) 35%, var(--border));
  background: var(--accent-soft);
}

.callout p:last-child {
  margin-bottom: 0 !important;
}

.two-col-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
  margin-bottom: 0.5rem;
}

.info-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.15rem 1.2rem;
  box-shadow: var(--shadow);
}

.info-card-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--heading);
  margin-bottom: 0.65rem;
}

.info-card-note {
  margin-top: 0.85rem !important;
  margin-bottom: 0 !important;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.bullet-list.compact {
  margin-top: 0;
}

.bullet-list.compact li {
  font-size: 0.9rem;
}

/* ---------- Journey timeline ---------- */
.journey-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 0.35rem;
  border-left: 2px solid var(--border);
}

.journey-step {
  position: relative;
  padding: 0 0 1.35rem 1.35rem;
}

.journey-step:last-child {
  padding-bottom: 0;
}

.journey-dot {
  position: absolute;
  left: -0.4rem;
  top: 0.35rem;
  width: 0.7rem;
  height: 0.7rem;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.journey-step:last-child .journey-dot {
  background: var(--accent);
}

.journey-title {
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--heading);
  margin-bottom: 0.25rem;
}

.journey-content p {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 0 !important;
}

.journey-current {
  color: var(--text) !important;
  font-weight: 500;
}

/* ---------- Status badges (variants) ---------- */
.status-progress {
  background: color-mix(in srgb, #f59e0b 18%, var(--bg-elevated));
  color: #b45309;
}

[data-theme="dark"] .status-progress {
  background: color-mix(in srgb, #fbbf24 16%, transparent);
  color: #fbbf24;
}

.status-lab {
  background: color-mix(in srgb, #10b981 16%, var(--bg-elevated));
  color: #047857;
}

[data-theme="dark"] .status-lab {
  background: color-mix(in srgb, #34d399 14%, transparent);
  color: #34d399;
}

.status-learning {
  background: color-mix(in srgb, #8b5cf6 14%, var(--bg-elevated));
  color: #6d28d9;
}

[data-theme="dark"] .status-learning {
  background: color-mix(in srgb, #a78bfa 14%, transparent);
  color: #c4b5fd;
}

/* ---------- Experience ---------- */
.exp-list {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.exp-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.15rem 1.25rem;
  box-shadow: var(--shadow);
}

.exp-meta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 0.75rem;
  margin-bottom: 0.25rem;
}

.exp-role {
  font-size: 1rem;
  font-weight: 600;
  color: var(--heading);
}

.exp-org {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--accent);
  margin-bottom: 0.15rem !important;
}

.exp-dates {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem !important;
  font-variant-numeric: tabular-nums;
}

.exp-desc {
  font-size: 0.875rem;
  color: var(--text);
  margin-bottom: 0 !important;
}

/* ---------- Projects ---------- */
.tier-label {
  font-size: 0.82rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin: 1.75rem 0 0.85rem;
  font-family: var(--font-mono);
}

.tier-label:first-of-type {
  margin-top: 0.25rem;
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
}

.project-grid-featured {
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}

.project-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  transition: box-shadow var(--transition), transform var(--transition),
    border-color var(--transition);
}

.project-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: color-mix(in srgb, var(--accent) 30%, var(--border));
}

.project-card-featured {
  border-color: color-mix(in srgb, var(--accent) 22%, var(--border));
}

.project-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.project-icon {
  font-size: 1.5rem;
  line-height: 1;
}

.project-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--heading);
  margin-bottom: 0.5rem;
}

.project-problem {
  font-size: 0.82rem;
  color: var(--text);
  margin-bottom: 0.55rem !important;
  line-height: 1.55;
}

.project-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  flex: 1;
  margin-bottom: 0.75rem !important;
}

.pipeline {
  margin: 0 0 0.75rem;
  padding: 0.55rem 0.7rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow-x: auto;
}

.pipeline-code {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  line-height: 1.45;
  color: var(--text-muted);
  white-space: nowrap;
}

.project-bullets {
  margin: 0 0 0.85rem 1.1rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.project-bullets li {
  margin-bottom: 0.3rem;
}

.project-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 0.85rem;
}

.project-link {
  font-size: 0.85rem;
  font-weight: 600;
  margin-top: auto;
}

/* ---------- Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 2rem;
  align-items: start;
}

.contact-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.contact-list li {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.contact-label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.contact-form {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.35rem 1.4rem;
  box-shadow: var(--shadow);
}

.form-note {
  font-size: 0.8rem !important;
  color: var(--text-muted) !important;
  margin-bottom: 1rem !important;
}

.form-field {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  margin-bottom: 0.9rem;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--heading);
}

.form-field input,
.form-field textarea {
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 0.75rem;
  transition: border-color var(--transition), box-shadow var(--transition);
  resize: vertical;
}

.form-field input:focus,
.form-field textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.form-field input::placeholder,
.form-field textarea::placeholder {
  color: var(--text-muted);
  opacity: 0.7;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  color: #fff;
  background: var(--accent);
  border: none;
  border-radius: 8px;
  padding: 0.65rem 1.25rem;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition);
}

.btn-primary:hover {
  background: var(--accent-hover);
}

.btn-primary:active {
  transform: scale(0.98);
}

/* Dark mode: ensure button text contrast on light blue accent */
[data-theme="dark"] .btn-primary {
  color: #0f1115;
}

.form-status {
  font-size: 0.85rem;
  margin-top: 0.75rem;
  min-height: 1.25em;
}

.form-status.success {
  color: #059669;
}

[data-theme="dark"] .form-status.success {
  color: #34d399;
}

.form-status.error {
  color: #dc2626;
}

/* ---------- Footer ---------- */
.site-footer {
  margin: 0 auto;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
}

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .mobile-header {
    display: flex;
  }

  .sidebar {
    transform: translateX(-100%);
    width: min(300px, 85vw);
    box-shadow: none;
  }

  body.nav-open .sidebar {
    transform: translateX(0);
    box-shadow: var(--shadow-md);
  }

  .main-content {
    margin-left: 0;
    padding: calc(var(--mobile-header-h) + 1.75rem) 1.25rem 3rem;
  }

  .sidebar-theme {
    /* Dùng toggle trên mobile header; ẩn bản sidebar nếu muốn gọn hơn */
  }

  .contact-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .section-title {
    font-size: 1.5rem;
  }

  .hero-block {
    padding: 1.15rem 1rem;
  }

  .pipeline-code {
    white-space: normal;
    word-break: break-word;
  }

  .project-grid-featured {
    grid-template-columns: 1fr;
  }

  html {
    scroll-padding-top: calc(var(--mobile-header-h) + 1rem);
  }

  .section {
    scroll-margin-top: calc(var(--mobile-header-h) + 1rem);
  }
}

@media (max-width: 480px) {
  .skills-grid,
  .project-grid {
    grid-template-columns: 1fr;
  }

  .cert-card {
    flex-direction: column;
    align-items: flex-start;
  }

  .main-content {
    padding-left: 1rem;
    padding-right: 1rem;
  }

  .avatar {
    width: 120px;
    height: 120px;
  }
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}

/* ---------- Print (optional CV-like) ---------- */
@media print {
  .sidebar,
  .mobile-header,
  .theme-toggle,
  .contact-form,
  .sidebar-overlay {
    display: none !important;
  }

  .main-content {
    margin: 0;
    padding: 0;
  }

  .section {
    break-inside: avoid;
  }
}