/* ============================================================
   Bai Xiaojie — Personal Website
   Design System: Apple (dl_builtin_apple)
   Font: PingFang SC priority for Chinese, SF Pro for Latin
   ============================================================ */

/* --- Design Tokens (Light) --- */
:root {
  /* Brand Blue — Apple System Blue #007AFF */
  --brand-500: #007aff;
  --brand-400: #2e8dff;
  --brand-600: #0064d6;
  --brand-50: #e8f2ff;

  /* Background */
  --bg-white: #ffffff;
  --bg-primary: #ffffff;
  --bg-secondary: #f5f5f7;
  --bg-tertiary: #f2f2f7;
  --bg-elevated: #ffffff;
  --bg-grouped: #f2f2f7;

  /* Text */
  --text-primary: #1d1d1f;
  --text-secondary: #3c3c43;
  --text-tertiary: #6e6e73;
  --text-quaternary: #8e8e93;
  --text-on-dark: #f5f5f7;

  /* Separators */
  --separator: rgba(60, 60, 67, 0.12);
  --separator-opaque: #c6c6c8;

  /* Fill */
  --fill-tertiary: rgba(118, 118, 128, 0.12);
  --fill-secondary: rgba(118, 118, 128, 0.08);
  --fill-primary: rgba(120, 120, 128, 0.2);

  /* Typography — PingFang SC first for Chinese */
  --font-display: "SF Pro Display", "PingFang SC", "Helvetica Neue", "Noto Sans CJK SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-text: "SF Pro Text", "PingFang SC", "Helvetica Neue", "Noto Sans CJK SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: "SF Mono", "Menlo", "Monaco", "JetBrains Mono", Consolas, monospace;

  /* Layout */
  --max-width: 800px;
  --section-padding: 96px;
  --content-padding: 24px;

  /* Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-pill: 980px;

  /* Shadows (Apple HIG) */
  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.04), 0 0 1px rgba(0, 0, 0, 0.08);
  --shadow-card-hover: 0 4px 16px rgba(0, 0, 0, 0.08), 0 0 1px rgba(0, 0, 0, 0.08);
  --shadow-float: 0 8px 32px rgba(0, 0, 0, 0.12);
  --shadow-product: rgba(0, 0, 0, 0.2) 0px 4px 24px;

  /* Motion */
  --ease-spring: cubic-bezier(0.175, 0.885, 0.32, 1.275);
  --ease-out: cubic-bezier(0.25, 0.1, 0.25, 1);
  --ease-apple: cubic-bezier(0.28, 0.11, 0.32, 1);
  --duration-fast: 250ms;
  --duration-normal: 400ms;
  --duration-slow: 700ms;
}

/* --- Dark Mode disabled (fixed light theme) --- */

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

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

body {
  font-family: var(--font-text);
  font-size: 17px;
  font-weight: 400;
  line-height: 1.47;
  letter-spacing: -0.022em;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* --- Reveal Animations --- */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity var(--duration-slow) var(--ease-apple),
              transform var(--duration-slow) var(--ease-apple);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-scale {
  opacity: 0;
  transform: scale(0.95);
  transition: opacity var(--duration-normal) var(--ease-spring),
              transform var(--duration-normal) var(--ease-spring);
}

.reveal-scale.visible {
  opacity: 1;
  transform: scale(1);
}

.reveal-stagger > .reveal:nth-child(1) { transition-delay: 0ms; }
.reveal-stagger > .reveal:nth-child(2) { transition-delay: 120ms; }
.reveal-stagger > .reveal:nth-child(3) { transition-delay: 240ms; }

@keyframes heroEntrance {
  0% {
    opacity: 0;
    transform: translateY(40px) scale(0.96);
    filter: blur(4px);
  }
  100% {
    opacity: 1;
    transform: translateY(0) scale(1);
    filter: blur(0px);
  }
}

@keyframes avatarPop {
  0% {
    opacity: 0;
    transform: scale(0.8);
  }
  60% {
    transform: scale(1.03);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes lineExpand {
  from { transform: scaleX(0); }
  to { transform: scaleX(1); }
}

@keyframes shimmer {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

/* --- Navigation — Apple Floating Capsule --- */
.site-nav {
  position: sticky;
  top: 12px;
  z-index: 1000;
  padding: 0 24px;
}

.nav-inner {
  max-width: 480px;
  margin: 0 auto;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border: 0.5px solid var(--separator);
  border-radius: var(--radius-pill);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

.nav-brand {
  position: absolute;
  left: 20px;
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.022em;
  opacity: 0.85;
  transition: opacity var(--duration-fast) var(--ease-out);
}

.nav-brand:hover {
  opacity: 1;
}

.nav-links {
  display: flex;
  gap: 4px;
  list-style: none;
}

.nav-links a {
  font-family: var(--font-text);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: -0.016em;
  color: var(--text-tertiary);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-out),
              background var(--duration-fast) var(--ease-out);
  min-height: 30px;
  padding: 0 12px;
  border-radius: 7px;
  display: flex;
  align-items: center;
}

.nav-links a:hover {
  color: var(--text-primary);
  background: var(--fill-secondary);
}

.nav-links a.active {
  color: var(--brand-500);
  background: var(--brand-50);
}

/* Mobile hamburger */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  width: 44px;
  height: 44px;
  position: absolute;
  left: var(--content-padding);
}

.nav-toggle span {
  display: block;
  width: 17px;
  height: 1px;
  background: var(--text-primary);
  position: absolute;
  top: 50%;
  left: 50%;
  transition: transform var(--duration-fast) var(--ease-out),
              opacity var(--duration-fast) var(--ease-out);
}

.nav-toggle span:nth-child(1) { transform: translate(-50%, -5px); }
.nav-toggle span:nth-child(2) { transform: translate(-50%, 0); }
.nav-toggle span:nth-child(3) { transform: translate(-50%, 5px); }

.nav-toggle.open span:nth-child(1) { transform: translate(-50%, 0) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translate(-50%, 0) rotate(-45deg); }

/* === HERO === */
.hero {
  position: relative;
  min-height: 85vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px var(--content-padding) 80px;
  overflow: hidden;
}

/* Subtle gradient orb behind hero */
.hero::before {
  content: "";
  position: absolute;
  top: -20%;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 800px;
  border-radius: 50%;
  background: radial-gradient(
    ellipse at center,
    rgba(0, 122, 255, 0.06) 0%,
    rgba(0, 122, 255, 0.02) 40%,
    transparent 70%
  );
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 640px;
}

.hero-avatar {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  object-fit: cover;
  box-shadow: var(--shadow-product);
  animation: avatarPop 0.8s var(--ease-spring) 0.1s both;
  transition: transform var(--duration-normal) var(--ease-spring);
}

.hero-avatar:hover {
  transform: scale(1.06);
}

.hero-eyebrow {
  display: inline-block;
  font-family: var(--font-text);
  font-size: 14px;
  font-weight: 500;
  color: var(--brand-500);
  letter-spacing: -0.016em;
  margin-top: 32px;
  animation: heroEntrance var(--duration-slow) var(--ease-apple) 0.2s both;
}

.hero-name {
  font-family: var(--font-display);
  font-size: 56px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.04em;
  line-height: 1.08;
  margin-top: 12px;
  animation: heroEntrance var(--duration-slow) var(--ease-apple) 0.3s both;
}

.hero-tagline {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 400;
  color: var(--text-secondary);
  letter-spacing: 0.012em;
  line-height: 1.42;
  margin-top: 16px;
  animation: heroEntrance var(--duration-slow) var(--ease-apple) 0.45s both;
}

.hero-cta-row {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 36px;
  animation: heroEntrance var(--duration-slow) var(--ease-apple) 0.6s both;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-text);
  font-size: 17px;
  font-weight: 400;
  letter-spacing: -0.022em;
  text-decoration: none;
  border-radius: var(--radius-pill);
  transition: transform var(--duration-fast) var(--ease-apple),
              box-shadow var(--duration-fast) var(--ease-apple);
  min-height: 50px;
  padding: 12px 24px;
}

.btn:active {
  transform: scale(0.96);
}

.btn-primary {
  background: var(--brand-500);
  color: #ffffff;
  box-shadow: 0 0 0 0 rgba(0, 122, 255, 0);
}

.btn-primary:hover {
  box-shadow: 0 4px 16px rgba(0, 122, 255, 0.25);
}

.btn-secondary {
  background: var(--fill-tertiary);
  color: var(--brand-500);
  border: 1px solid var(--separator);
}

.btn-secondary:hover {
  background: var(--fill-secondary);
}

/* === SECTION SYSTEM === */
.section {
  padding: var(--section-padding) 0;
}

.section--grouped {
  background: var(--bg-grouped);
}

.section--white {
  background: var(--bg-white);
}

.section--dark {
  background: var(--bg-secondary);
  color: var(--text-on-dark);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--content-padding);
}

/* === SECTION HEADER === */
.section-header {
  margin-bottom: 40px;
}

.section-eyebrow {
  font-family: var(--font-text);
  font-size: 14px;
  font-weight: 600;
  color: var(--brand-500);
  letter-spacing: -0.016em;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.section-dark .section-eyebrow {
  color: var(--brand-400);
}

.section-title {
  font-family: var(--font-display);
  font-size: 40px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  line-height: 1.1;
}

.section-dark .section-title {
  color: var(--text-on-dark);
}

.section-subtitle {
  font-family: var(--font-text);
  font-size: 19px;
  font-weight: 400;
  color: var(--text-tertiary);
  letter-spacing: -0.016em;
  line-height: 1.47;
  margin-top: 12px;
  max-width: 560px;
}

.section-dark .section-subtitle {
  color: var(--text-quaternary);
}

/* Decorative line under section title */
.section-line {
  width: 48px;
  height: 4px;
  background: var(--brand-500);
  border-radius: 2px;
  margin-top: 16px;
}

/* === BIO === */
.bio-text {
  font-family: var(--font-text);
  font-size: 19px;
  font-weight: 400;
  color: var(--text-secondary);
  letter-spacing: -0.016em;
  line-height: 1.65;
}

.section-dark .bio-text {
  color: rgba(245, 245, 247, 0.75);
}

.bio-text p + p {
  margin-top: 20px;
}

/* === EDUCATION CARDS === */
.edu-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

@media (min-width: 569px) {
  .edu-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.edu-card {
  background: var(--bg-elevated);
  border-radius: var(--radius-xl);
  padding: 28px;
  border: 1px solid var(--separator);
  box-shadow: var(--shadow-card);
  transition: transform var(--duration-normal) var(--ease-spring),
              box-shadow var(--duration-normal) var(--ease-apple);
  position: relative;
  overflow: hidden;
}

.section--dark .edu-card {
  background: var(--bg-tertiary);
  border-color: var(--separator);
}

.edu-card::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--brand-500);
  opacity: 0;
  transition: opacity var(--duration-normal) var(--ease-apple);
}

.edu-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
}

.edu-card:hover::after {
  opacity: 1;
}

.edu-badge {
  display: inline-block;
  font-family: var(--font-text);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--brand-500);
  background: var(--brand-50);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
}

.section-dark .edu-badge {
  background: rgba(0, 122, 255, 0.15);
  color: var(--brand-400);
}

.edu-school {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.016em;
  line-height: 1.3;
}

.section-dark .edu-school {
  color: var(--text-on-dark);
}

.edu-degree {
  font-family: var(--font-text);
  font-size: 15px;
  font-weight: 500;
  color: var(--brand-500);
  margin-top: 4px;
}

.section-dark .edu-degree {
  color: var(--brand-400);
}

.edu-major {
  font-family: var(--font-text);
  font-size: 14px;
  font-weight: 400;
  color: var(--text-tertiary);
  letter-spacing: -0.016em;
  line-height: 1.5;
  margin-top: 12px;
}

.section-dark .edu-major {
  color: var(--text-quaternary);
}

.edu-time {
  font-family: var(--font-text);
  font-size: 12px;
  font-weight: 500;
  color: var(--text-quaternary);
  letter-spacing: 0;
  margin-top: 16px;
}

/* === CONTACT === */
.contact-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.contact-row {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
  border-radius: var(--radius-lg);
  background: var(--bg-elevated);
  border: 1px solid var(--separator);
  transition: transform var(--duration-fast) var(--ease-apple),
              box-shadow var(--duration-fast) var(--ease-apple);
}

.contact-row:active {
  transform: scale(0.98);
}

.contact-icon-box {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--fill-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.contact-icon-box svg {
  width: 20px;
  height: 20px;
  color: var(--brand-500);
}

.contact-label {
  font-size: 12px;
  font-weight: 500;
  color: var(--text-quaternary);
  letter-spacing: 0;
}

.contact-val {
  font-size: 17px;
  font-weight: 400;
  color: var(--text-primary);
  letter-spacing: -0.022em;
}

.contact-val a {
  color: var(--brand-500);
  text-decoration: none;
  transition: opacity var(--duration-fast) var(--ease-out);
}

.contact-val a:hover {
  opacity: 0.75;
  text-decoration: underline;
}

/* === FOOTER === */
.site-footer {
  padding: 32px 0;
  background: var(--bg-grouped);
  border-top: 1px solid var(--separator);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--content-padding);
  text-align: center;
  font-family: var(--font-text);
  font-size: 12px;
  font-weight: 400;
  color: var(--text-quaternary);
  letter-spacing: 0;
  line-height: 2;
}

.footer-inner a {
  color: var(--brand-500);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-out);
}

.footer-inner a:hover {
  color: var(--brand-600);
}

/* === PAGE HEADER (Resume / Blog) === */
.page-hero {
  padding: 80px 0 48px;
  text-align: center;
}

.page-hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--content-padding);
}

.page-hero-title {
  font-family: var(--font-display);
  font-size: 48px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.037em;
  line-height: 1.08;
}

.page-hero-sub {
  font-family: var(--font-text);
  font-size: 19px;
  font-weight: 400;
  color: var(--text-tertiary);
  letter-spacing: -0.016em;
  line-height: 1.47;
  margin-top: 8px;
}

/* === RESUME TIMELINE === */
.timeline {
  position: relative;
  padding-left: 36px;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 12px;
  bottom: 12px;
  width: 2px;
  background: var(--separator);
  border-radius: 1px;
}

.timeline-item {
  position: relative;
  padding-bottom: 48px;
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-dot {
  position: absolute;
  left: -36px;
  top: 10px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--bg-primary);
  border: 3px solid var(--brand-500);
  transition: background var(--duration-fast) var(--ease-apple),
              transform var(--duration-fast) var(--ease-spring);
}

.timeline-item:hover .timeline-dot {
  background: var(--brand-500);
  transform: scale(1.2);
}

.timeline-school {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.022em;
  line-height: 1.29;
}

.timeline-degree {
  font-family: var(--font-text);
  font-size: 17px;
  font-weight: 600;
  color: var(--brand-500);
  letter-spacing: -0.022em;
  margin-top: 4px;
}

.timeline-major {
  font-family: var(--font-text);
  font-size: 17px;
  font-weight: 400;
  color: var(--text-tertiary);
  letter-spacing: -0.022em;
  line-height: 1.47;
  margin-top: 6px;
}

.timeline-time {
  font-family: var(--font-text);
  font-size: 14px;
  font-weight: 500;
  color: var(--text-quaternary);
  letter-spacing: -0.016em;
  margin-top: 8px;
}

/* === SKILLS === */
.skills-wrap {
  margin-top: var(--section-padding);
}

.skill-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.skill-pill {
  font-family: var(--font-text);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: -0.016em;
  padding: 10px 20px;
  border-radius: var(--radius-pill);
  background: var(--fill-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--separator);
  transition: all var(--duration-fast) var(--ease-apple);
  cursor: default;
}

.skill-pill:hover {
  background: var(--brand-50);
  color: var(--brand-500);
  border-color: var(--brand-500);
  transform: translateY(-1px);
}

/* === BLOG LIST === */
.blog-list {
  list-style: none;
}

.blog-item {
  padding: 28px 0;
  border-bottom: 1px solid var(--separator);
  transition: transform var(--duration-fast) var(--ease-apple);
}

.blog-item:first-child {
  border-top: 1px solid var(--separator);
}

.blog-item:last-child {
  border-bottom: none;
}

.blog-item:hover {
  transform: translateX(4px);
}

.blog-item-title {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 600;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.022em;
  line-height: 1.29;
  transition: color var(--duration-fast) var(--ease-apple);
  display: inline-block;
}

.blog-item-title:hover {
  color: var(--brand-500);
}

.blog-item-date {
  font-family: var(--font-text);
  font-size: 14px;
  font-weight: 500;
  color: var(--text-quaternary);
  letter-spacing: -0.016em;
  margin-top: 6px;
}

.blog-item-summary {
  font-family: var(--font-text);
  font-size: 17px;
  font-weight: 400;
  color: var(--text-tertiary);
  letter-spacing: -0.022em;
  line-height: 1.47;
  margin-top: 10px;
}

/* === BLOG ARTICLE === */
.article-hero {
  padding: 80px 0 40px;
}

.article-hero-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--content-padding);
}

.article-title {
  font-family: var(--font-display);
  font-size: 34px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.022em;
  line-height: 1.29;
}

.article-date {
  font-family: var(--font-text);
  font-size: 15px;
  font-weight: 500;
  color: var(--text-quaternary);
  letter-spacing: -0.016em;
  margin-top: 10px;
}

.article-body {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 40px var(--content-padding) 64px;
}

.article-body p {
  font-family: var(--font-text);
  font-size: 19px;
  font-weight: 400;
  letter-spacing: -0.016em;
  line-height: 1.65;
  color: var(--text-secondary);
  margin-bottom: 20px;
}

.article-body h2 {
  font-family: var(--font-display);
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.022em;
  line-height: 1.21;
  margin-top: 56px;
  margin-bottom: 20px;
}

.article-body h3 {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.022em;
  line-height: 1.27;
  margin-top: 40px;
  margin-bottom: 14px;
}

.article-body code {
  font-family: var(--font-mono);
  font-size: 15px;
  background: var(--fill-tertiary);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  color: var(--brand-500);
}

.article-body pre {
  background: var(--bg-secondary);
  padding: 20px 24px;
  border-radius: var(--radius-lg);
  overflow-x: auto;
  word-break: break-all;
  white-space: pre-wrap;
  border: 1px solid var(--separator);
}

.article-body pre code {
  background: none;
  padding: 0;
  border-radius: 0;
  color: inherit;
}

.article-back {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-text);
  font-size: 17px;
  font-weight: 500;
  color: var(--brand-500);
  text-decoration: none;
  letter-spacing: -0.022em;
  padding: 20px 0;
  transition: gap var(--duration-fast) var(--ease-apple);
}

.article-back:hover {
  gap: 14px;
  text-decoration: underline;
}

/* === 404 === */
.not-found {
  text-align: center;
  padding: 160px var(--content-padding);
}

.not-found h1 {
  font-family: var(--font-display);
  font-size: 64px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.04em;
  line-height: 1;
}

.not-found p {
  font-size: 19px;
  color: var(--text-tertiary);
  margin-top: 16px;
}

.not-found a {
  display: inline-block;
  margin-top: 40px;
  font-size: 17px;
  font-weight: 400;
  color: #ffffff;
  background: var(--brand-500);
  padding: 14px 28px;
  border-radius: var(--radius-pill);
  text-decoration: none;
  transition: transform var(--duration-fast) var(--ease-apple);
}

.not-found a:active {
  transform: scale(0.96);
}

/* === RESPONSIVE === */
@media (max-width: 768px) {
  :root {
    --section-padding: 64px;
    --content-padding: 20px;
  }

  body {
    font-size: 16px;
  }

  .nav-brand {
    display: none;
  }

  .nav-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 52px;
    left: 24px;
    right: 24px;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    flex-direction: column;
    padding: 12px;
    gap: 4px;
    border: 0.5px solid var(--separator);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    width: 100%;
    justify-content: center;
    font-size: 16px;
    padding: 12px 0;
    border-radius: 10px;
    letter-spacing: -0.022em;
  }

  .hero {
    min-height: auto;
    padding: 80px var(--content-padding) 64px;
  }

  .hero-avatar {
    width: 110px;
    height: 110px;
  }

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

  .hero-tagline {
    font-size: 19px;
  }

  .section-title {
    font-size: 28px;
  }

  .page-hero-title {
    font-size: 34px;
  }

  .article-title {
    font-size: 28px;
  }

  .edu-grid {
    grid-template-columns: 1fr;
  }

  .edu-card {
    padding: 22px;
  }

  .timeline {
    padding-left: 28px;
  }

  .timeline-dot {
    left: -28px;
    width: 14px;
    height: 14px;
    border-width: 2.5px;
  }

  .timeline-school {
    font-size: 19px;
  }

  .blog-item-title {
    font-size: 19px;
  }

  .btn {
    padding: 12px 20px;
    font-size: 16px;
    min-height: 44px;
  }
}

@media (min-width: 769px) {
  .nav-toggle {
    display: none !important;
  }
}

/* === PRINT === */
@media print {
  .site-nav, .site-footer, .nav-toggle {
    display: none !important;
  }
  body {
    background: #fff;
    color: #000;
  }
  .edu-card, .contact-row, .skill-pill, .timeline-item {
    break-inside: avoid;
  }
}