/* ============ Theme variables ============ */
:root {
  --accent: #7c5cff;
  --accent-2: #22d3ee;
  --gradient: linear-gradient(135deg, #7c5cff 0%, #22d3ee 100%);
  --radius: 16px;
  --nav-h: 64px;
  --font: 'Be Vietnam Pro', system-ui, -apple-system, 'Segoe UI', sans-serif;
}

html[data-theme="dark"] {
  --bg: #0a0e1a;
  --bg-soft: #0e1424;
  --card: rgba(255, 255, 255, 0.045);
  --card-solid: #121a2e;
  --border: rgba(255, 255, 255, 0.09);
  --text: #e8ebf4;
  --muted: #9aa4ba;
  --nav-bg: rgba(10, 14, 26, 0.75);
  --shadow: 0 12px 40px rgba(0, 0, 0, 0.45);
  --glow: rgba(124, 92, 255, 0.35);
  --chip-bg: rgba(124, 92, 255, 0.12);
}

html[data-theme="light"] {
  --bg: #f5f7fc;
  --bg-soft: #eef1f9;
  --card: #ffffff;
  --card-solid: #ffffff;
  --border: #e2e7f2;
  --text: #1c2436;
  --muted: #5d6880;
  --nav-bg: rgba(245, 247, 252, 0.8);
  --shadow: 0 12px 32px rgba(28, 36, 54, 0.1);
  --glow: rgba(124, 92, 255, 0.18);
  --chip-bg: rgba(124, 92, 255, 0.08);
}

/* ============ Base ============ */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background 0.4s ease, color 0.4s ease;
}
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; }
.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }
.accent {
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ============ Reveal animation ============ */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity 0.7s ease, transform 0.7s ease; }
.reveal.visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  * { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; }
}

/* ============ Nav ============ */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  background: var(--nav-bg);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s, background 0.3s;
}
.nav.scrolled { border-bottom-color: var(--border); }
.nav-inner {
  max-width: 1100px; margin: 0 auto; padding: 0 24px;
  height: var(--nav-h);
  display: flex; align-items: center; gap: 20px;
}
.brand { font-size: 1.3rem; font-weight: 800; letter-spacing: 0.5px; white-space: nowrap; }
.nav-links { display: flex; gap: 26px; margin-left: auto; }
.nav-links a {
  font-size: 0.92rem; font-weight: 500; color: var(--muted);
  position: relative; padding: 4px 0; transition: color 0.25s;
}
.nav-links a::after {
  content: ''; position: absolute; left: 0; bottom: -2px;
  width: 0; height: 2px; background: var(--gradient);
  border-radius: 2px; transition: width 0.3s ease;
}
.nav-links a:hover, .nav-links a.active { color: var(--text); }
.nav-links a:hover::after, .nav-links a.active::after { width: 100%; }
.nav-controls { display: flex; gap: 10px; margin-left: 8px; }
.ctrl-btn {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 38px; height: 34px; padding: 0 10px;
  border-radius: 10px; border: 1px solid var(--border);
  background: var(--card); color: var(--text);
  font-weight: 700; font-size: 0.82rem;
  transition: border-color 0.25s, box-shadow 0.25s, transform 0.15s;
}
.ctrl-btn:hover { border-color: var(--accent); box-shadow: 0 0 0 3px var(--glow); transform: translateY(-1px); }
html[data-theme="dark"] .icon-sun { display: none; }
html[data-theme="light"] .icon-moon { display: none; }
.hamburger { display: none; background: none; border: none; flex-direction: column; gap: 5px; margin-left: auto; padding: 6px; }
.hamburger span { width: 22px; height: 2px; background: var(--text); border-radius: 2px; transition: 0.3s; }

/* ============ Hero ============ */
.hero {
  position: relative; min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  text-align: center; overflow: hidden;
  background:
    radial-gradient(ellipse 60% 50% at 20% 10%, var(--glow), transparent 60%),
    radial-gradient(ellipse 50% 40% at 85% 80%, rgba(34, 211, 238, 0.12), transparent 60%),
    var(--bg);
}
#particles { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero-content { position: relative; z-index: 2; padding: 110px 24px 60px; max-width: 760px; }

.hero-hello { color: var(--accent-2); font-weight: 600; letter-spacing: 2px; text-transform: uppercase; font-size: 0.85rem; }
.hero-name {
  font-size: clamp(2.4rem, 7vw, 4rem); font-weight: 800; line-height: 1.15;
  margin: 8px 0 10px;
  background: linear-gradient(120deg, var(--text) 30%, var(--accent) 70%, var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero-role { font-size: clamp(1.1rem, 3vw, 1.5rem); color: var(--muted); font-weight: 500; min-height: 2.2em; }
.caret { color: var(--accent-2); animation: blink 1s step-end infinite; font-weight: 400; }
@keyframes blink { 50% { opacity: 0; } }

.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; margin-top: 28px; }
.btn {
  display: inline-flex; align-items: center; gap: 9px;
  padding: 13px 26px; border-radius: 999px;
  font-size: 0.95rem; font-weight: 600; border: none;
  transition: transform 0.2s, box-shadow 0.3s, border-color 0.25s;
}
.btn-primary {
  background: var(--gradient); color: #fff;
  box-shadow: 0 8px 24px var(--glow);
}
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 14px 34px var(--glow); }
.btn-primary:active { transform: translateY(-1px); }
.btn-primary.loading { opacity: 0.7; pointer-events: none; }
.btn-ghost { background: transparent; color: var(--text); border: 1px solid var(--border); }
.btn-ghost:hover { border-color: var(--accent); transform: translateY(-3px); box-shadow: 0 8px 24px var(--glow); }

.hero-contacts { display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; margin-top: 30px; }
.hero-contacts a {
  display: inline-flex; align-items: center; gap: 8px;
  color: var(--muted); font-size: 0.9rem; transition: color 0.25s, transform 0.2s;
}
.hero-contacts a:hover { color: var(--accent-2); transform: translateY(-2px); }
.hero-contacts svg { flex-shrink: 0; }

/* ============ Stats ============ */
.stats { padding: 70px 0 10px; }
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 18px; }
.stat-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 26px 20px; text-align: center;
  transition: transform 0.25s, border-color 0.25s, box-shadow 0.3s;
}
.stat-card:hover { transform: translateY(-5px); border-color: var(--accent); box-shadow: 0 10px 30px var(--glow); }
.stat-value { font-size: 2.2rem; font-weight: 800; }
.stat-label { color: var(--muted); font-size: 0.88rem; margin-top: 4px; }

/* ============ Sections ============ */
.section { padding: 90px 0 30px; }
.section-title { font-size: clamp(1.5rem, 4vw, 2rem); font-weight: 800; margin-bottom: 36px; display: flex; align-items: baseline; gap: 10px; }
.section-sub { color: var(--muted); font-size: 0.95rem; margin: -24px 0 28px; }

/* ============ About ============ */
.about-grid { display: grid; grid-template-columns: 1.6fr 1fr; gap: 30px; align-items: start; }
.about-text { color: var(--muted); font-size: 1.05rem; }
.about-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 24px; display: flex; flex-direction: column; gap: 14px;
}
.about-card .row { display: flex; align-items: center; gap: 12px; font-size: 0.93rem; }
.about-card .row svg { color: var(--accent); flex-shrink: 0; }
.about-card .row a:hover { color: var(--accent-2); }

/* ============ Skills ============ */
.skills-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 18px; }
.skill-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px; transition: transform 0.25s, border-color 0.25s, box-shadow 0.3s;
}
.skill-card:hover { transform: translateY(-4px); border-color: var(--accent); box-shadow: 0 10px 28px var(--glow); }
.skill-card h3 { font-size: 1rem; font-weight: 700; margin-bottom: 14px; display: flex; align-items: center; gap: 8px; }
.skill-card h3::before { content: ''; width: 8px; height: 8px; border-radius: 50%; background: var(--gradient); }
.skill-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.skill-tag {
  background: var(--chip-bg); border: 1px solid var(--border);
  color: var(--text); font-size: 0.82rem; font-weight: 500;
  padding: 5px 12px; border-radius: 999px;
  transition: border-color 0.25s, transform 0.2s;
}
.skill-tag:hover { border-color: var(--accent-2); transform: scale(1.06); }

/* ============ Timeline ============ */
.timeline { position: relative; padding-left: 30px; }
.timeline::before {
  content: ''; position: absolute; left: 7px; top: 6px; bottom: 6px;
  width: 2px; background: linear-gradient(180deg, var(--accent), var(--accent-2));
  border-radius: 2px; opacity: 0.5;
}
.tl-item { position: relative; padding: 0 0 46px 26px; }
.tl-item::before {
  content: ''; position: absolute; left: -30px; top: 6px;
  width: 16px; height: 16px; border-radius: 50%;
  background: var(--bg); border: 3px solid var(--accent);
  box-shadow: 0 0 0 4px var(--glow);
}
.tl-period {
  display: inline-block; background: var(--chip-bg); color: var(--accent);
  border: 1px solid var(--border); font-size: 0.8rem; font-weight: 700;
  padding: 4px 14px; border-radius: 999px; margin-bottom: 10px;
}
html[data-theme="dark"] .tl-period { color: var(--accent-2); }
.tl-company { font-size: 1.25rem; font-weight: 750; }
.tl-role { color: var(--muted); font-weight: 500; margin-bottom: 12px; }
.tl-highlights { list-style: none; display: flex; flex-direction: column; gap: 8px; margin-bottom: 16px; }
.tl-highlights li { position: relative; padding-left: 22px; color: var(--muted); font-size: 0.95rem; }
.tl-highlights li::before { content: '▹'; position: absolute; left: 0; color: var(--accent-2); }
.tl-apps-label { font-size: 0.8rem; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; color: var(--muted); margin: 12px 0 8px; }
.tl-chips { display: flex; flex-wrap: wrap; gap: 8px; }
.app-chip {
  display: inline-flex; align-items: center; gap: 7px;
  background: var(--card); border: 1px solid var(--border);
  padding: 5px 12px 5px 6px; border-radius: 999px;
  font-size: 0.82rem; font-weight: 500;
  transition: border-color 0.25s, transform 0.2s, box-shadow 0.25s;
}
.app-chip:hover { border-color: var(--accent); transform: translateY(-2px); box-shadow: 0 6px 16px var(--glow); }
.app-chip img, .app-chip .chip-ico {
  width: 22px; height: 22px; border-radius: 6px; object-fit: cover;
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--chip-bg); font-size: 0.7rem; font-weight: 700;
}

/* ============ Apps grid ============ */
.apps-filters { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 28px; }
.filter-btn {
  background: var(--card); border: 1px solid var(--border); color: var(--muted);
  padding: 8px 20px; border-radius: 999px; font-size: 0.88rem; font-weight: 600;
  transition: all 0.25s;
}
.filter-btn:hover { border-color: var(--accent); color: var(--text); }
.filter-btn.active { background: var(--gradient); color: #fff; border-color: transparent; box-shadow: 0 6px 18px var(--glow); }

.apps-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(290px, 1fr)); gap: 18px; }
.app-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px; display: flex; flex-direction: column; gap: 12px;
  transition: transform 0.2s ease, border-color 0.25s, box-shadow 0.3s, opacity 0.3s;
  transform-style: preserve-3d; will-change: transform;
}
.app-card.hidden-card { display: none; }
.app-card:hover { border-color: var(--accent); box-shadow: 0 14px 36px var(--glow); }
.app-card.has-store { cursor: pointer; position: relative; }
.store-hint {
  position: absolute; top: 12px; right: 14px;
  color: var(--muted); font-size: 0.95rem; font-weight: 700;
  opacity: 0; transform: translate(-3px, 3px);
  transition: opacity 0.25s, transform 0.25s, color 0.25s;
}
.app-card.has-store:hover .store-hint { opacity: 1; transform: none; color: var(--accent-2); }
.app-card-head { display: flex; align-items: center; gap: 14px; }
.app-icon, .app-icon-fallback {
  width: 54px; height: 54px; border-radius: 14px; object-fit: cover; flex-shrink: 0;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
}
.app-icon-fallback {
  display: flex; align-items: center; justify-content: center;
  background: var(--gradient); color: #fff; font-weight: 800; font-size: 1.2rem;
}
.app-name { font-weight: 700; font-size: 1rem; line-height: 1.3; }
.app-meta { display: flex; gap: 12px; margin-top: 3px; font-size: 0.8rem; color: var(--muted); }
.app-meta .star { color: #fbbf24; }
.app-desc { color: var(--muted); font-size: 0.88rem; flex: 1; }
.app-badges { display: flex; gap: 8px; flex-wrap: wrap; }
.badge {
  font-size: 0.72rem; font-weight: 700; letter-spacing: 0.4px;
  padding: 3px 10px; border-radius: 6px; text-transform: uppercase;
}
.badge-android { background: rgba(61, 220, 132, 0.12); color: #3ddc84; }
.badge-ios { background: rgba(120, 170, 255, 0.14); color: #78aaff; }
.badge-dev { background: rgba(124, 92, 255, 0.14); color: #a18bff; }
.badge-maint { background: rgba(251, 191, 36, 0.13); color: #d9a514; }
.badge-personal { background: rgba(34, 211, 238, 0.13); color: #22d3ee; }
html[data-theme="light"] .badge-android { color: #1da95e; }
html[data-theme="light"] .badge-ios { color: #2f6fde; }
html[data-theme="light"] .badge-dev { color: #6a48e8; }
html[data-theme="light"] .badge-personal { color: #0e96b5; }

/* ============ Footer ============ */
.footer { border-top: 1px solid var(--border); margin-top: 70px; padding: 36px 0; }
.footer-inner { display: flex; flex-direction: column; align-items: center; gap: 14px; text-align: center; }
.footer-contacts { display: flex; gap: 20px; flex-wrap: wrap; justify-content: center; }
.footer-contacts a { color: var(--muted); font-size: 0.9rem; display: inline-flex; gap: 7px; align-items: center; }
.footer-contacts a:hover { color: var(--accent-2); }
.footer-note { color: var(--muted); font-size: 0.83rem; }

/* ============ Phone modal (call / Zalo) ============ */
.phone-modal {
  position: fixed; inset: 0; z-index: 200;
  display: flex; align-items: center; justify-content: center;
  background: rgba(5, 8, 16, 0.55);
  backdrop-filter: blur(5px); -webkit-backdrop-filter: blur(5px);
  opacity: 0; pointer-events: none; transition: opacity 0.25s ease;
}
.phone-modal.show { opacity: 1; pointer-events: auto; }
.phone-modal-card {
  position: relative;
  background: var(--card-solid); border: 1px solid var(--border);
  border-radius: 20px; padding: 30px 26px 26px;
  width: min(90vw, 340px);
  display: flex; flex-direction: column; gap: 12px; text-align: center;
  box-shadow: var(--shadow);
  transform: translateY(14px) scale(0.97); transition: transform 0.25s ease;
}
.phone-modal.show .phone-modal-card { transform: none; }
.phone-modal-title { color: var(--muted); font-size: 0.88rem; }
.phone-modal-num { font-size: 1.45rem; font-weight: 800; letter-spacing: 1px; margin-bottom: 6px; }
.phone-modal-card .btn { justify-content: center; }
.btn-zalo { background: #0068ff; color: #fff; box-shadow: 0 8px 24px rgba(0, 104, 255, 0.35); }
.btn-zalo:hover { transform: translateY(-3px); box-shadow: 0 14px 34px rgba(0, 104, 255, 0.45); }
.phone-modal-close {
  position: absolute; top: 10px; right: 10px;
  width: 32px; height: 32px; border-radius: 10px;
  background: var(--card); border: 1px solid var(--border); color: var(--muted);
  font-size: 0.85rem; transition: color 0.2s, border-color 0.2s;
}
.phone-modal-close:hover { color: var(--text); border-color: var(--accent); }

/* ============ Back to top ============ */
.back-top {
  position: fixed; right: 22px; bottom: 22px; z-index: 90;
  width: 44px; height: 44px; border-radius: 12px;
  background: var(--gradient); color: #fff; border: none; font-size: 1.1rem;
  opacity: 0; pointer-events: none; transform: translateY(10px);
  transition: opacity 0.3s, transform 0.3s; box-shadow: 0 8px 20px var(--glow);
}
.back-top.show { opacity: 1; pointer-events: auto; transform: none; }
.back-top:hover { transform: translateY(-3px); }

/* ============ Responsive ============ */
@media (max-width: 820px) {
  .hamburger { display: flex; }
  .nav-links {
    position: absolute; top: var(--nav-h); left: 0; right: 0;
    flex-direction: column; gap: 0; background: var(--nav-bg);
    backdrop-filter: blur(14px); border-bottom: 1px solid var(--border);
    max-height: 0; overflow: hidden; transition: max-height 0.35s ease; margin-left: 0;
  }
  .nav-links.open { max-height: 320px; }
  .nav-links a { padding: 13px 24px; border-top: 1px solid var(--border); }
  .nav-links a::after { display: none; }
  .nav-controls { margin-left: 0; }
  .about-grid { grid-template-columns: 1fr; }
  .timeline { padding-left: 22px; }
  .tl-item { padding-left: 18px; }
}