/* ===========================================================
   Hao Vo — Personal Website
   Minimal · Blue & White · Subtle motion
   =========================================================== */

:root {
  --blue-700: #1d4ed8;
  --blue-600: #2563eb;
  --blue-500: #3b82f6;
  --blue-400: #60a5fa;
  --blue-100: #dbeafe;
  --blue-50:  #eff6ff;

  --ink:      #0b1220;
  --ink-soft: #334155;
  --muted:    #64748b;
  --line:     #e2e8f0;
  --white:    #ffffff;
  --paper:    #f8fafc;

  --radius:   18px;
  --radius-sm:12px;
  --shadow:   0 1px 2px rgba(15, 23, 42, .04), 0 12px 32px -12px rgba(37, 99, 235, .18);
  --shadow-lg:0 30px 60px -24px rgba(37, 99, 235, .30);

  --maxw: 1080px;
  --ease: cubic-bezier(.22, 1, .36, 1);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, sans-serif;
  color: var(--ink);
  background: var(--white);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3 { font-family: "Space Grotesk", "Inter", sans-serif; line-height: 1.1; }

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

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

/* ---------- Decorative background ---------- */
.bg-grid {
  position: fixed;
  inset: 0;
  z-index: -2;
  background-image:
    linear-gradient(to right, rgba(37, 99, 235, .06) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(37, 99, 235, .06) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 30%, transparent 80%);
}

.bg-glow {
  position: fixed;
  top: -240px;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 600px;
  z-index: -1;
  background: radial-gradient(closest-side, rgba(59, 130, 246, .22), transparent 70%);
  filter: blur(20px);
  pointer-events: none;
}

/* ---------- Layout helpers ---------- */
.section {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 88px 24px;
  scroll-margin-top: 90px;
}

.section__head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 40px;
}

.section__index {
  font-family: "Space Grotesk", sans-serif;
  font-size: .9rem;
  font-weight: 600;
  color: var(--blue-600);
  letter-spacing: .12em;
}

.section__title {
  font-size: clamp(1.7rem, 3.5vw, 2.4rem);
  margin: 0;
  position: relative;
}

.section__title::after {
  content: "";
  display: block;
  width: 54px;
  height: 4px;
  margin-top: 14px;
  border-radius: 99px;
  background: linear-gradient(90deg, var(--blue-600), var(--blue-400));
}

/* ---------- Navigation ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, .72);
  border-bottom: 1px solid transparent;
  transition: border-color .3s var(--ease), background .3s var(--ease);
}

.nav.is-scrolled {
  border-color: var(--line);
  background: rgba(255, 255, 255, .85);
}

.nav__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Brand: 3D flip card — 🌾 Hao Vo  <->  🌱 Thanh Tam */
.nav__brand {
  font-family: "Space Grotesk", sans-serif;
  font-weight: 700;
  font-size: 1.1rem;
  display: inline-block;
  perspective: 700px;
  -webkit-tap-highlight-color: transparent;
}

.nav__brand-flip {
  display: grid;
  transform-style: preserve-3d;
  transition: transform .8s cubic-bezier(.45, .05, .3, 1);
  will-change: transform;
}

.nav__brand:hover .nav__brand-flip,
.nav__brand:focus-visible .nav__brand-flip {
  transform: rotateY(180deg);
}

/* Both faces share one grid cell, so the pill sizes to the wider name */
.nav__face {
  grid-area: 1 / 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  white-space: nowrap;
  gap: 8px;
  padding: 6px 14px 6px 10px;
  border-radius: 999px;
  background: var(--blue-50);
  border: 1px solid var(--blue-100);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, .06);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

.nav__face--back {
  transform: rotateY(180deg);
  color: var(--blue-700);
  background: #f0fdf4;
  border-color: #bbf7d0;
  box-shadow: 0 0 0 3px rgba(22, 163, 74, .07);
}

/* Click: spin an extra full turn, then navigate.
   540deg lands on the back face from either resting state (0 or 180). */
.nav__brand.is-spinning .nav__brand-flip {
  transform: rotateY(540deg);
  transition-duration: .95s;
}

.nav__logo {
  font-size: 1.15rem;
  line-height: 1;
}

@media (prefers-reduced-motion: reduce) {
  .nav__brand-flip,
  .nav__brand.is-spinning .nav__brand-flip { transition: none; }
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 30px;
}

.nav__links a {
  font-size: .95rem;
  font-weight: 500;
  color: var(--ink-soft);
  transition: color .2s var(--ease);
}

.nav__links a:hover { color: var(--blue-600); }

.nav__cv {
  padding: 8px 16px;
  border-radius: 99px;
  background: var(--blue-600);
  color: #fff !important;
  box-shadow: var(--shadow);
}

.nav__cv:hover { background: var(--blue-700); }

.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: 0;
  cursor: pointer;
  padding: 6px;
}

.nav__toggle span {
  width: 24px;
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
  transition: transform .3s var(--ease), opacity .3s var(--ease);
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 13px 24px;
  border-radius: 99px;
  font-weight: 600;
  font-size: .96rem;
  transition: transform .2s var(--ease), box-shadow .2s var(--ease), background .2s var(--ease);
}

.btn--primary {
  background: var(--blue-600);
  color: #fff;
  box-shadow: var(--shadow);
}

.btn--primary:hover {
  background: var(--blue-700);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn--ghost {
  background: var(--white);
  color: var(--blue-700);
  border: 1px solid var(--line);
}

.btn--ghost:hover {
  border-color: var(--blue-400);
  transform: translateY(-2px);
}

.btn--icon {
  gap: 8px;
  padding: 11px 20px;
}

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

/* ---------- Hero ---------- */
.hero {
  position: relative;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 80px 24px 64px;
  display: grid;
  grid-template-columns: 1.4fr .9fr;
  gap: 56px;
  align-items: center;
}

/* Autonomous-driving / robotics perception scene */
.hero__scene {
  position: absolute;
  inset: -60px -10vw -40px -10vw;
  width: auto;
  z-index: 0;
  pointer-events: none;
  mask-image: radial-gradient(ellipse 75% 85% at 50% 55%, #000 35%, transparent 78%);
  -webkit-mask-image: radial-gradient(ellipse 75% 85% at 50% 55%, #000 35%, transparent 78%);
}

.hero__content,
.hero__avatar { position: relative; z-index: 1; }

.hero__eyebrow {
  font-family: "Space Grotesk", sans-serif;
  text-transform: uppercase;
  letter-spacing: .16em;
  font-size: .78rem;
  font-weight: 600;
  color: var(--blue-600);
  margin: 0 0 18px;
}

.hero__title {
  font-size: clamp(2.3rem, 5.5vw, 3.7rem);
  font-weight: 700;
  margin: 0 0 22px;
  letter-spacing: -.02em;
}

.grad {
  display: inline-block;
  background: linear-gradient(100deg, var(--blue-600), var(--blue-400));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.highlight {
  font-weight: 700;
  color: var(--blue-700);
}

.hero__lede {
  font-size: 1.12rem;
  color: var(--ink-soft);
  max-width: 540px;
  margin: 0 0 32px;
}

.hero__lede strong { color: var(--ink); font-weight: 600; }

.hero__actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  margin-bottom: 38px;
}

.hero__meta {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 22px;
  padding: 0;
  margin: 0;
  font-size: .9rem;
  color: var(--muted);
}

.hero__meta li { display: flex; align-items: center; gap: 8px; }

.dotk {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--blue-500);
}

/* Avatar */
.hero__avatar {
  position: relative;
  justify-self: center;
}

.avatar-ring {
  width: 280px;
  height: 280px;
  border-radius: 50%;
  padding: 7px;
  background: conic-gradient(from 140deg, var(--blue-400), var(--blue-600), var(--blue-100), var(--blue-500));
  box-shadow: var(--shadow-lg);
  animation: float 6s ease-in-out infinite;
}

.avatar-ring img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  border: 5px solid var(--white);
  background: var(--paper);
}

.avatar-badge {
  position: absolute;
  bottom: 14px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--white);
  border: 1px solid var(--line);
  padding: 8px 16px;
  border-radius: 99px;
  font-size: .82rem;
  font-weight: 600;
  color: var(--ink-soft);
  box-shadow: var(--shadow);
  white-space: nowrap;
}

.avatar-badge__pulse {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--blue-500);
  position: relative;
}

.avatar-badge__pulse::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: var(--blue-500);
  animation: pulse 2s ease-out infinite;
}

@keyframes pulse {
  0%   { transform: scale(1); opacity: .7; }
  100% { transform: scale(3); opacity: 0; }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-12px); }
}

/* ---------- About ---------- */
.about {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}

.about p {
  font-size: 1.08rem;
  color: var(--ink-soft);
  margin: 0;
  line-height: 1.75;
}

.about strong { color: var(--blue-700); }

.about a {
  color: inherit;
  font-weight: 600;
  text-decoration: underline;
  text-decoration-color: var(--blue-400);
  text-underline-offset: 3px;
}

/* News (right column) */
.news {
  border-left: 3px solid var(--blue-100);
  padding-left: 24px;
}

.news__title {
  margin: 0 0 18px;
  font-size: .82rem;
  text-transform: uppercase;
  letter-spacing: .14em;
  color: var(--blue-600);
}

.news__list {
  list-style: none;
  margin: 0;
  padding: 0 8px 0 0;
  display: grid;
  gap: 20px;
  max-height: 300px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--blue-100) transparent;
}

.news__list::-webkit-scrollbar {
  width: 6px;
}

.news__list::-webkit-scrollbar-thumb {
  background: var(--blue-100);
  border-radius: 99px;
}

.news__list::-webkit-scrollbar-track {
  background: transparent;
}

.news__item {
  display: grid;
  grid-template-columns: 72px 24px 1fr;
  gap: 10px;
  align-items: start;
}

.news__date {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 3px 8px;
  border-radius: 999px;
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--blue-700);
  background: var(--blue-50);
  border: 1px solid var(--blue-100);
  white-space: nowrap;
}

.news__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  font-size: 1.05rem;
  line-height: 1;
}

.news__text {
  margin: 0;
  font-size: .96rem;
  line-height: 1.45;
  color: var(--ink-soft);
}

.news__text strong { color: var(--blue-700); }

.about__cards {
  display: grid;
  gap: 14px;
}

.card-mini {
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 18px 20px;
  background: var(--white);
  transition: transform .25s var(--ease), box-shadow .25s var(--ease), border-color .25s var(--ease);
}

.card-mini:hover {
  transform: translateY(-3px);
  border-color: var(--blue-200, #bfdbfe);
  box-shadow: var(--shadow);
}

.card-mini h3 {
  margin: 0 0 6px;
  font-size: .76rem;
  text-transform: uppercase;
  letter-spacing: .12em;
  color: var(--blue-600);
}

.card-mini p { margin: 0; font-weight: 600; font-size: 1.02rem; }

.card-mini span { font-size: .86rem; color: var(--muted); }

/* ---------- Publications ---------- */
.pubs {
  display: grid;
  gap: 18px;
}

.pub {
  display: grid;
  grid-template-columns: 168px 1fr;
  gap: 24px;
  align-items: center;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--white);
  transition: transform .3s var(--ease), box-shadow .3s var(--ease), border-color .3s var(--ease);
}

.pub:hover {
  transform: translateY(-4px);
  border-color: var(--blue-400);
  box-shadow: var(--shadow-lg);
}

.pub__thumb {
  display: block;
  aspect-ratio: 16 / 10;
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: var(--blue-50);
  border: 1px solid var(--line);
}

.pub__thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .4s var(--ease);
}

.pub:hover .pub__thumb img { transform: scale(1.05); }

.pub__tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 10px;
}

.tag {
  font-size: .74rem;
  font-weight: 600;
  padding: 4px 11px;
  border-radius: 99px;
  background: var(--paper);
  color: var(--ink-soft);
  border: 1px solid var(--line);
}

.tag--accent {
  background: var(--blue-600);
  color: #fff;
  border-color: var(--blue-600);
}

.tag--review {
  background: var(--blue-50);
  color: var(--blue-700);
  border-color: var(--blue-100);
}

.pub__title {
  font-size: 1.16rem;
  margin: 0 0 8px;
  font-weight: 600;
  letter-spacing: -.01em;
}

.pub__authors { margin: 0 0 2px; font-size: .92rem; color: var(--ink-soft); }
.pub__authors strong { color: var(--blue-700); }
.pub__venue { margin: 0; font-size: .88rem; color: var(--muted); }

.pub__links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.pub__btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: 999px;
  font-size: .82rem;
  font-weight: 600;
  color: var(--ink);
  background: #fff;
  border: 1px solid #d4d4d8;
  text-decoration: none;
  transition: background .2s var(--ease), color .2s var(--ease), border-color .2s var(--ease), transform .2s var(--ease);
}

.pub__btn svg { width: 15px; height: 15px; }

.pub__btn:hover {
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
  transform: translateY(-1px);
}

.pub__btn--soon {
  color: var(--muted);
  background: var(--paper);
  border-style: dashed;
  cursor: default;
}

.pub__btn--soon:hover {
  background: var(--paper);
  color: var(--muted);
  border-color: #d4d4d8;
  transform: none;
}

/* ---------- Awards ---------- */
.awards {
  list-style: none;
  margin: 0;
  padding: 0;
}

.award {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 20px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.award:last-child { border-bottom: none; }

.award__year {
  font-family: "Space Grotesk", sans-serif;
  font-weight: 600;
  font-size: .92rem;
  color: var(--muted);
  padding-top: .12em;
}

.award__body h3 {
  margin: 0;
  font-size: 1rem;
  font-weight: 600;
}

.award__body p { margin: 0; color: var(--ink-soft); font-size: .92rem; }
.award__desc { color: var(--muted); font-size: .88rem; margin-top: 4px !important; }

/* ---------- Footer ---------- */
.footer {
  margin-top: 40px;
  padding: 80px 24px;
  background:
    radial-gradient(ellipse 70% 100% at 50% 0%, var(--blue-50), transparent 70%);
  border-top: 1px solid var(--line);
  text-align: center;
}

.footer__inner { max-width: 680px; margin: 0 auto; }

.footer__title {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  margin: 0 0 12px;
}

.footer__sub { color: var(--ink-soft); margin: 0 0 28px; font-size: 1.05rem; }

.footer__links {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 36px;
}

.footer__copy { font-size: .85rem; color: var(--muted); margin: 0; }

/* ---------- Reveal animation ---------- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .7s var(--ease), transform .7s var(--ease);
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .avatar-ring, .avatar-badge__pulse::after { animation: none; }
  html { scroll-behavior: auto; }
}

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .hero {
    grid-template-columns: 1fr;
    text-align: center;
    padding-top: 48px;
  }
  .hero__actions, .hero__meta { justify-content: center; }
  .hero__lede { margin-inline: auto; }
  .hero__avatar { order: -1; }
  .about { grid-template-columns: 1fr; gap: 32px; }
  .news { border-left: 0; padding-left: 0; }
}

@media (max-width: 720px) {
  .nav__links {
    position: fixed;
    inset: 64px 0 auto 0;
    flex-direction: column;
    gap: 8px;
    background: rgba(255, 255, 255, .97);
    backdrop-filter: blur(12px);
    padding: 20px 24px 28px;
    border-bottom: 1px solid var(--line);
    transform: translateY(-130%);
    transition: transform .35s var(--ease);
  }
  .nav__links.is-open { transform: translateY(0); }
  .nav__toggle { display: flex; }

  .pub { grid-template-columns: 1fr; }
  .pub__thumb { max-width: 240px; }

  .award {
    grid-template-columns: auto 1fr;
    gap: 14px;
  }
}