/* ===========================================
   KIEN DO — FRESH PORTFOLIO v2
   =========================================== */

/* --- Custom Properties --- */
:root {
  --bg: #0f0f0f;
  --bg-card: #1a1a1a;
  --bg-card-hover: #222;
  --surface: #252525;
  --border: #333;
  --text: #e8e8e8;
  --text-muted: #999;
  --text-dim: #666;
  --accent: #f06449;
  --accent-hover: #ff7a62;
  --accent-glow: rgba(240, 100, 73, 0.15);
  --accent2: #4ecdc4;
  --accent2-glow: rgba(78, 205, 196, 0.15);
  --white: #fff;
  --font: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --radius: 16px;
  --radius-sm: 10px;
  --radius-pill: 999px;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: var(--accent); text-decoration: none; transition: color 0.2s var(--ease); }
a:hover { color: var(--accent-hover); }

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

.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }

/* --- NAV --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 20px 0;
  transition: all 0.35s var(--ease);
}
.nav.scrolled {
  padding: 12px 0;
  background: rgba(15, 15, 15, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}
.nav-logo {
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
}
.nav-logo span { color: var(--accent); }
.nav-links { display: flex; gap: 32px; list-style: none; }
.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.02em;
  position: relative;
  padding: 4px 0;
  transition: color 0.2s var(--ease);
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s var(--ease);
}
.nav-links a:hover { color: var(--text); }
.nav-links a:hover::after { width: 100%; }

/* Mobile menu */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}
.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  margin: 6px 0;
  transition: all 0.3s var(--ease);
}

@media (max-width: 768px) {
  .nav-toggle { display: block; position: relative; z-index: 201; }
  .nav-logo { position: relative; z-index: 201; }
  .nav-links {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    height: 100dvh;
    z-index: 200;
    background-color: #0f0f0f;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 40px;
    visibility: hidden;
    opacity: 0;
    transition: opacity 0.35s var(--ease), visibility 0.35s;
  }
  .nav-links.open {
    visibility: visible;
    opacity: 1;
  }
  .nav-links a { font-size: 24px; color: var(--text); }
}

/* --- HERO --- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  padding: 120px 24px 80px;
}

.hero-bg {
  position: absolute;
  inset: 0;
  overflow: hidden;
  z-index: 0;
}
.hero-bg::before {
  content: '';
  position: absolute;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  top: 20%;
  left: 10%;
  animation: float 8s ease-in-out infinite;
}
.hero-bg::after {
  content: '';
  position: absolute;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, var(--accent2-glow) 0%, transparent 70%);
  bottom: 10%;
  right: 5%;
  animation: float 10s ease-in-out infinite reverse;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0); }
  50% { transform: translate(30px, -40px); }
}

.hero-content { position: relative; z-index: 1; }

.hero-photo {
  width: 160px;
  height: 160px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--border);
  margin: 0 auto 32px;
  box-shadow: 0 0 40px var(--accent-glow);
  transition: box-shadow 0.4s var(--ease);
}
.hero-photo:hover {
  box-shadow: 0 0 60px rgba(240, 100, 73, 0.3);
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 16px;
}
.hero h1 .highlight { color: var(--accent); }

.hero-tagline {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-muted);
  font-weight: 400;
  margin-bottom: 32px;
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--text-dim);
  animation: bounce-down 2s ease-in-out infinite;
}
@keyframes bounce-down {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(8px); }
}

/* --- SECTION --- */
.section {
  padding: 100px 0;
}
.section-header {
  margin-bottom: 56px;
}
.section-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 12px;
}
.section-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}

/* --- ABOUT --- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 48px;
  align-items: start;
}
@media (max-width: 768px) {
  .about-grid { grid-template-columns: 1fr; }
}

.about-quote {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  line-height: 1.3;
  color: var(--text);
  position: relative;
  padding-left: 20px;
  border-left: 3px solid var(--accent);
}

.about-body p {
  color: var(--text-muted);
  margin-bottom: 16px;
  font-size: 15px;
  line-height: 1.75;
}

/* --- EXPERIENCE --- */
.exp-list { display: flex; flex-direction: column; gap: 16px; }

.exp-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 32px;
  transition: all 0.3s var(--ease);
  cursor: default;
}
.exp-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
}

.exp-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 4px;
}
.exp-role {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
}
.exp-role .company { color: var(--accent); }
.exp-date {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-dim);
}
.exp-team {
  font-size: 14px;
  font-weight: 600;
  color: var(--accent2);
  margin-bottom: 8px;
}
.exp-desc {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 8px;
}
.exp-skills {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-dim);
}
.exp-links { margin-top: 12px; }
.exp-links a {
  font-size: 13px;
  font-weight: 600;
  margin-right: 16px;
}

.btn-more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 24px;
  padding: 10px 24px;
  font-size: 14px;
  font-weight: 600;
  color: var(--accent);
  background: transparent;
  border: 1.5px solid var(--accent);
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: all 0.25s var(--ease);
}
.btn-more:hover {
  background: var(--accent);
  color: var(--bg);
}

/* --- PROJECTS --- */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 40px;
}
.filter-chip {
  padding: 8px 18px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-muted);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: all 0.25s var(--ease);
}
.filter-chip:hover {
  border-color: var(--accent);
  color: var(--text);
}
.filter-chip.active {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--bg);
  font-weight: 600;
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.proj-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 28px;
  display: flex;
  flex-direction: column;
  transition: all 0.3s var(--ease);
}
.proj-card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
  box-shadow: 0 16px 48px rgba(0,0,0,0.3);
}
.proj-card.fade-out {
  opacity: 0;
  transform: scale(0.95);
  transition: opacity 0.4s var(--ease), transform 0.4s var(--ease);
}
.proj-card.d-none { display: none !important; }

.proj-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
}
.proj-tech {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 14px;
}
.proj-desc {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.7;
  flex-grow: 1;
}
.proj-links {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}
.proj-links a {
  font-size: 13px;
  font-weight: 600;
  margin-right: 16px;
}

/* --- PUBLICATIONS --- */
.pub-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.pub-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 32px;
  transition: all 0.3s var(--ease);
}
.pub-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
}
.pub-card.featured {
  background: linear-gradient(135deg, rgba(240,100,73,0.08), rgba(78,205,196,0.05));
  border-color: rgba(240,100,73,0.3);
}
.pub-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 4px;
}
.pub-source {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent);
  margin-bottom: 12px;
}
.pub-desc {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 12px;
}
.pub-link {
  font-size: 13px;
  font-weight: 600;
}

/* --- FOOTER --- */
.footer {
  padding: 48px 0;
  text-align: center;
  border-top: 1px solid var(--border);
}
.footer-socials {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 24px;
}
.social-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 1.5px solid var(--border);
  border-radius: 50%;
  color: var(--text-muted);
  font-size: 18px;
  transition: all 0.25s var(--ease);
}
.social-icon:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-3px);
  box-shadow: 0 4px 16px var(--accent-glow);
}
.footer-copy {
  font-size: 13px;
  color: var(--text-dim);
}

/* --- SCROLL REVEAL --- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- HERO ANIMATIONS --- */
.hero-enter {
  opacity: 0;
  transform: translateY(20px);
  animation: fadeUp 0.8s var(--ease) forwards;
}
.hero-enter:nth-child(1) { animation-delay: 0.1s; }
.hero-enter:nth-child(2) { animation-delay: 0.3s; }
.hero-enter:nth-child(3) { animation-delay: 0.5s; }
.hero-enter:nth-child(4) { animation-delay: 0.7s; }
.hero-enter:nth-child(5) { animation-delay: 0.9s; }

@keyframes fadeUp {
  to { opacity: 1; transform: translateY(0); }
}

/* --- REDUCED MOTION --- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
}