/* ==========================================================================
   BÁC SĨ NGUYỄN DUY ANH — DESIGN SYSTEM (CRAFTED WITH IMPECCABLE & A11Y)
   Aesthetic: Clinical Clarity · Fresh Ice Cyan · Editorial Authority
   ========================================================================== */

:root {
  /* Surface & Ink Tokens */
  --bg: #f0f7f9;
  --bg-elev: #ffffff;
  --bg-subtle: #e6f2f5;
  --ink: #163844;
  --ink-pure: #0b252e;
  --muted: #486a77;
  --muted-dim: #6c8d9b;
  --line: #cfe4eb;
  --line-subtle: #e1eff3;

  /* Accent & Interactive */
  --accent: #0284c7;
  --accent-hover: #0369a1;
  --accent-surface: #e0f2fe;
  --accent-contrast: #ffffff;

  /* Layout & Geometry */
  --max: 48rem;
  --prose-max: 68ch;
  --pad: 1.25rem;
  --radius-sm: 6px;
  --radius: 12px;
  --radius-lg: 16px;

  /* Typography Stacks */
  --serif: "Source Serif 4", "Playfair Display", Georgia, serif;
  --sans: "Be Vietnam Pro", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

/* --------------------------------------------------------------------------
   Reset & Base Standards
   -------------------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background-color: var(--bg);
  color-scheme: light;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 1.05rem;
  line-height: 1.72;
  color: var(--ink);
  background-color: var(--bg);
  min-height: 100dvh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

/* Themed Browser Surfaces */
::selection {
  background-color: #bae6fd;
  color: var(--ink-pure);
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

img, svg {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.25em;
  transition: color 0.15s ease, text-decoration-color 0.15s ease;
}

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

.skip {
  position: absolute;
  left: -9999px;
  top: 0.5rem;
  background: var(--accent);
  color: var(--accent-contrast);
  font-weight: 600;
  padding: 0.65rem 1rem;
  border-radius: var(--radius-sm);
  z-index: 10000;
  text-decoration: none;
}

.skip:focus {
  left: 1rem;
}

.wrap {
  width: min(100% - 2 * var(--pad), var(--max));
  margin-inline: auto;
}

/* --------------------------------------------------------------------------
   Site Header & Navigation
   -------------------------------------------------------------------------- */
.site-header {
  border-bottom: 1px solid var(--line);
  background: rgba(240, 247, 249, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  position: sticky;
  top: 0;
  z-index: 100;
  width: 100%;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.25rem;
  padding: 0.75rem 0;
  min-height: 4.25rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  color: var(--ink-pure);
  text-decoration: none;
  flex-shrink: 0;
}

.brand:hover .brand-text {
  color: var(--accent);
}

.brand-mark {
  width: 42px;
  height: 42px;
  flex-shrink: 0;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.brand-text {
  display: flex;
  flex-direction: column;
  font-size: 1.12rem;
  font-weight: 700;
  line-height: 1.2;
  color: var(--ink-pure);
  letter-spacing: -0.01em;
  transition: color 0.15s ease;
}

.brand-sub {
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--muted);
  margin-top: 0.18rem;
  letter-spacing: 0;
}

.nav {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 1.35rem;
  font-size: 0.95rem;
  font-weight: 500;
}

.nav a {
  color: var(--ink);
  text-decoration: none;
  padding: 0.4rem 0.25rem;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  transition: color 0.15s ease;
  white-space: nowrap;
}

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

.nav a[aria-current="page"] {
  color: var(--accent);
  font-weight: 700;
  box-shadow: inset 0 -2px 0 var(--accent);
}

/* --------------------------------------------------------------------------
   Typography & Headings
   -------------------------------------------------------------------------- */
h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 700;
  line-height: 1.28;
  color: var(--ink-pure);
  letter-spacing: -0.018em;
  text-wrap: balance;
}

h1 {
  font-size: clamp(1.9rem, 4vw, 2.4rem);
  margin: 0 0 0.75rem;
}

h2 {
  font-size: clamp(1.4rem, 3vw, 1.75rem);
  margin: 2.2rem 0 0.85rem;
}

h3 {
  font-size: 1.22rem;
  margin: 1.6rem 0 0.6rem;
}

/* --------------------------------------------------------------------------
   Hero / Intro Section
   -------------------------------------------------------------------------- */
.intro {
  display: grid;
  gap: 1.85rem;
  padding: 2.25rem 0 2rem;
  border-bottom: 1px solid var(--line);
  margin-bottom: 2.25rem;
}

@media (min-width: 640px) {
  .intro {
    grid-template-columns: 140px 1fr;
    align-items: start;
  }
}

.portrait {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  object-fit: cover;
  object-position: center 10%;
  border: 3px solid var(--bg-elev);
  background: var(--bg-elev);
  box-shadow: 0 4px 16px rgba(11, 37, 46, 0.08);
}

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

.intro h1 {
  font-size: clamp(1.85rem, 4vw, 2.35rem);
  margin: 0 0 0.5rem;
}

.specialty-tagline {
  font-family: var(--sans);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent);
  margin: 0 0 0.65rem;
  letter-spacing: 0.01em;
}

.lead {
  font-size: 1.1rem;
  color: var(--ink);
  font-weight: 450;
  margin: 0 0 0.75rem;
  line-height: 1.62;
}

.meta-line {
  margin: 0 0 1.15rem;
  font-size: 0.96rem;
  color: var(--muted);
  line-height: 1.55;
}

.hero-cta-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  margin-top: 0.35rem;
}

/* --------------------------------------------------------------------------
   Buttons & Controls (A11y Touch Targets >= 44px)
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-family: var(--sans);
  font-weight: 600;
  font-size: 0.94rem;
  padding: 0.65rem 1.15rem;
  min-height: 44px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  cursor: pointer;
  transition: all 0.15s ease;
  line-height: 1;
}

.btn svg {
  width: 17px;
  height: 17px;
  flex-shrink: 0;
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-contrast) !important;
  border: 1px solid transparent;
  box-shadow: 0 2px 8px rgba(2, 132, 199, 0.2);
}

.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(2, 132, 199, 0.3);
}

.btn-secondary {
  background: var(--bg-elev);
  color: var(--ink-pure) !important;
  border: 1px solid var(--line);
}

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent) !important;
  transform: translateY(-1px);
}

/* --------------------------------------------------------------------------
   E-E-A-T Trust Verification Strip (Pure SVGs, No Emojis)
   -------------------------------------------------------------------------- */
.trust-bar {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 0.85rem;
  padding: 1.15rem 1.35rem;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: 2.75rem;
}

.trust-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
}

.trust-icon-svg {
  width: 22px;
  height: 22px;
  color: var(--accent);
  flex-shrink: 0;
  margin-top: 0.15rem;
}

.trust-content strong {
  display: block;
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--ink-pure);
  line-height: 1.3;
}

.trust-content span {
  display: block;
  font-size: 0.82rem;
  color: var(--muted);
  margin-top: 0.15rem;
}

/* --------------------------------------------------------------------------
   Specialty Grid & Clinical Pillars
   -------------------------------------------------------------------------- */
.section-block {
  margin-bottom: 3.25rem;
}

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.35rem;
}

.section-subtitle {
  margin: 0 0 1.35rem;
  font-size: 0.98rem;
  color: var(--muted);
}

.specialty-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
  gap: 1rem;
}

.specialty-card {
  padding: 1.4rem 1.45rem;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  transition: transform 0.15s ease, border-color 0.15s ease;
}

.specialty-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}

.specialty-card-icon {
  width: 28px;
  height: 28px;
  color: var(--accent);
  margin-bottom: 0.85rem;
}

.specialty-card h3 {
  font-family: var(--serif);
  font-size: 1.18rem;
  color: var(--ink-pure);
  margin: 0 0 0.5rem;
  line-height: 1.35;
}

.specialty-card p {
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.6;
  color: var(--muted);
}

/* --------------------------------------------------------------------------
   Clinical Workflow Cards
   -------------------------------------------------------------------------- */
.workflow-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1rem;
}

.workflow-card {
  padding: 1.3rem 1.35rem;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.workflow-step-tag {
  font-family: var(--sans);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 0.4rem;
}

.workflow-card h3 {
  font-family: var(--sans);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--ink-pure);
  margin: 0 0 0.45rem;
}

.workflow-card p {
  margin: 0;
  font-size: 0.92rem;
  color: var(--muted);
  line-height: 1.55;
}

/* --------------------------------------------------------------------------
   Article Lists & Cards
   -------------------------------------------------------------------------- */
.post-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.post {
  border-bottom: 1px solid var(--line);
}

.post:first-child {
  border-top: 1px solid var(--line);
}

.post a {
  display: block;
  padding: 1.4rem 0;
  text-decoration: none;
  color: inherit;
}

.post h2 {
  font-family: var(--serif);
  font-size: 1.25rem;
  color: var(--ink-pure);
  margin: 0 0 0.45rem;
  transition: color 0.15s ease;
}

.post a:hover h2 {
  color: var(--accent);
}

.post .dek {
  margin: 0 0 0.45rem;
  font-size: 0.96rem;
  color: var(--muted);
  line-height: 1.55;
}

.post-meta {
  font-size: 0.84rem;
  font-weight: 500;
  color: var(--muted-dim);
  margin: 0;
}

/* --------------------------------------------------------------------------
   Article Prose & Editorial Layout (Max Measure 68ch)
   -------------------------------------------------------------------------- */
.prose {
  max-width: var(--prose-max);
}

.prose p {
  margin: 1.25rem 0;
}

.prose ul, .prose ol {
  margin: 1.25rem 0;
  padding-left: 1.4rem;
}

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

.byline {
  display: flex;
  align-items: center;
  gap: 0.9rem;
  padding: 1.15rem 0;
  border-bottom: 1px solid var(--line);
  margin-bottom: 1.75rem;
}

.byline-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  object-fit: cover;
  object-position: center 10%;
  border: 2px solid var(--bg-elev);
}

.byline div {
  display: flex;
  flex-direction: column;
  font-size: 0.92rem;
}

.byline strong {
  color: var(--ink-pure);
}

.byline span {
  color: var(--muted);
  font-size: 0.84rem;
}

/* Key Takeaways Box (Crafted Elevation) */
.key-takeaways {
  margin: 1.85rem 0 1.75rem;
  padding: 1.35rem 1.5rem;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.key-takeaways-head {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--sans);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.85rem;
}

.key-takeaways-head svg {
  width: 18px;
  height: 18px;
}

.key-takeaways ul {
  list-style: none !important;
  padding: 0 !important;
  margin: 0 !important;
}

.key-takeaways li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 0.7rem !important;
  font-size: 0.98rem;
  line-height: 1.62;
  color: var(--ink);
}

.key-takeaways li:last-child {
  margin-bottom: 0 !important;
}

.key-takeaways li::before {
  content: "—";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--accent);
  font-weight: 700;
}

/* Table of Contents Box */
.toc-box {
  margin: 1.5rem 0 2.25rem;
  padding: 1.25rem 1.45rem;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.toc-title {
  font-family: var(--sans);
  font-size: 0.88rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--ink-pure);
  margin-bottom: 0.75rem;
}

.toc-box ul {
  margin: 0 !important;
  padding-left: 1.3rem !important;
}

.toc-box li {
  margin-bottom: 0.4rem !important;
  font-size: 0.95rem;
}

.toc-box a {
  color: var(--ink);
  text-decoration: none;
}

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

.article-figure {
  margin: 2rem 0;
}

.article-figure img {
  border-radius: var(--radius);
  border: 1px solid var(--line);
  width: 100%;
}

figcaption {
  margin-top: 0.65rem;
  font-size: 0.86rem;
  color: var(--muted);
  text-align: center;
  font-style: italic;
}

.note-box {
  margin: 2rem 0;
  padding: 1.3rem 1.4rem;
  background: var(--bg-subtle);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.note-box h4 {
  margin: 0 0 0.5rem;
  font-size: 1.05rem;
}

.note-box p {
  margin: 0;
  font-size: 0.96rem;
}

/* --------------------------------------------------------------------------
   Booking & Hospital Guidance Card
   -------------------------------------------------------------------------- */
.booking-card {
  margin-top: 3.25rem;
  padding: 1.6rem 1.75rem;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}

.booking-card h3 {
  font-size: 1.25rem;
  margin: 0 0 0.5rem;
  color: var(--ink-pure);
}

.booking-card p {
  margin: 0 0 1rem;
  font-size: 0.98rem;
  line-height: 1.65;
  color: var(--ink);
}

.booking-card ul {
  margin: 0 0 1.25rem;
  padding-left: 1.3rem;
}

.booking-card li {
  font-size: 0.94rem;
  color: var(--ink);
  margin-bottom: 0.35rem;
}

.booking-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* --------------------------------------------------------------------------
   Related Posts Grid
   -------------------------------------------------------------------------- */
.related-posts {
  margin-top: 3.25rem;
  padding-top: 2rem;
  border-top: 1px solid var(--line);
}

.related-posts h3 {
  font-size: 1.35rem;
  margin: 0 0 1.2rem;
  color: var(--ink-pure);
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
}

.related-card {
  padding: 1.2rem 1.3rem;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-decoration: none;
  transition: transform 0.15s ease, border-color 0.15s ease;
  display: block;
}

.related-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}

.related-card h4 {
  font-family: var(--serif);
  margin: 0 0 0.4rem;
  font-size: 1.08rem;
  color: var(--ink-pure);
}

.related-card p {
  margin: 0;
  font-size: 0.88rem;
  color: var(--muted);
  line-height: 1.5;
}

/* --------------------------------------------------------------------------
   Site Footer
   -------------------------------------------------------------------------- */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 2.5rem 0 3rem;
  font-size: 0.88rem;
  color: var(--muted);
  line-height: 1.6;
}

.site-footer strong {
  color: var(--ink-pure);
}

.site-footer p {
  margin: 0 0 0.4rem;
}

/* --------------------------------------------------------------------------
   Floating Zalo Action Button (Impeccable Minimalist Medical Pill)
   -------------------------------------------------------------------------- */
.floating-zalo {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 999;
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  background: #0068ff;
  color: #ffffff !important;
  font-family: var(--sans);
  font-weight: 600;
  font-size: 0.88rem;
  padding: 0.65rem 1.1rem;
  border-radius: 999px;
  text-decoration: none;
  box-shadow: 0 4px 18px rgba(0, 104, 255, 0.35);
  transition: transform 0.15s ease, box-shadow 0.15s ease, background-color 0.15s ease;
}

.floating-zalo:hover {
  background: #0054cc;
  transform: translateY(-2px);
  box-shadow: 0 6px 22px rgba(0, 104, 255, 0.45);
}

.floating-zalo svg {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  fill: currentColor;
}

@media (max-width: 640px) {
  .floating-zalo span {
    display: none;
  }
  .floating-zalo {
    padding: 0.75rem;
    bottom: 1.15rem;
    right: 1.15rem;
    border-radius: 50%;
  }
}