/* =====================================================
   Khalil LAGHA — Portfolio · vanilla CSS, no framework
   Dark (default) + light theme · amber accent
   ===================================================== */

/* ---------- Custom properties ---------- */
:root {
  --font: "Space Grotesk", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  --radius: 16px;
  --radius-sm: 10px;
  --container: 1100px;
}

:root, [data-theme="dark"] {
  color-scheme: dark;
  --bg: #0a0e1c;
  --bg-alt: #0d1328;
  --surface: #111936;
  --text: #e9edf8;
  --muted: #a4aecb;
  --border: rgba(164, 174, 203, 0.17);
  --accent: #fbbf24;
  --accent-soft: rgba(251, 191, 36, 0.12);
  --btn-bg: #fbbf24;
  --btn-ink: #251a02;
  --logo-bg: #0b1120;
  --header-bg: rgba(10, 14, 28, 0.72);
  --shadow: 0 14px 40px rgba(0, 0, 0, 0.45);
  --glow: rgba(245, 158, 11, 0.16);
  --wave2: #5f6f9c;
  --grid-line: rgba(164, 174, 203, 0.055);
  --grid-line-hot: rgba(251, 191, 36, 0.18);
  --spot: rgba(251, 191, 36, 0.07);
  --accent-2: #f59e0b;
  --pcb: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cg fill='none' stroke='%23a4aecb' stroke-opacity='0.06'%3E%3Cpath d='M24 0v34l22 22h44'/%3E%3Ccircle cx='94' cy='56' r='3'/%3E%3Cpath d='M180 44h-34l-16 16v48'/%3E%3Ccircle cx='130' cy='112' r='3'/%3E%3Cpath d='M0 132h56l16-16'/%3E%3Ccircle cx='76' cy='112' r='2.5'/%3E%3Cpath d='M156 180v-28l-22-22'/%3E%3Ccircle cx='24' cy='0' r='2.5'/%3E%3Ccircle cx='156' cy='180' r='2.5'/%3E%3C/g%3E%3C/svg%3E");
}

[data-theme="light"] {
  color-scheme: light;
  --bg: #f7f8fc;
  --bg-alt: #eef1f8;
  --surface: #ffffff;
  --text: #161c31;
  --muted: #4b556f;
  --border: rgba(22, 28, 49, 0.14);
  --accent: #b45309;
  --accent-soft: rgba(180, 83, 9, 0.10);
  --btn-bg: #b45309;
  --btn-ink: #ffffff;
  --logo-bg: #161c31;
  --header-bg: rgba(247, 248, 252, 0.78);
  --shadow: 0 14px 36px rgba(22, 28, 49, 0.12);
  --glow: rgba(245, 158, 11, 0.14);
  --wave2: #93a0c2;
  --grid-line: rgba(22, 28, 49, 0.05);
  --grid-line-hot: rgba(180, 83, 9, 0.16);
  --spot: rgba(180, 83, 9, 0.05);
  --accent-2: #d97706;
  --pcb: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cg fill='none' stroke='%23161c31' stroke-opacity='0.05'%3E%3Cpath d='M24 0v34l22 22h44'/%3E%3Ccircle cx='94' cy='56' r='3'/%3E%3Cpath d='M180 44h-34l-16 16v48'/%3E%3Ccircle cx='130' cy='112' r='3'/%3E%3Cpath d='M0 132h56l16-16'/%3E%3Ccircle cx='76' cy='112' r='2.5'/%3E%3Cpath d='M156 180v-28l-22-22'/%3E%3Ccircle cx='24' cy='0' r='2.5'/%3E%3Ccircle cx='156' cy='180' r='2.5'/%3E%3C/g%3E%3C/svg%3E");
}

/* ---------- Reset-ish ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html { scroll-padding-top: 86px; }
@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}
body {
  font-family: var(--font);
  font-size: clamp(1rem, 0.35vw + 0.95rem, 1.0625rem);
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img, svg { display: block; max-width: 100%; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
ul, ol { padding: 0; list-style: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
h1, h2, h3 { line-height: 1.15; text-wrap: balance; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }
::selection { background: var(--accent); color: var(--btn-ink); }

.container {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: clamp(1rem, 4vw, 2rem);
}

.skip-link {
  position: absolute; z-index: 100; top: 0.6rem; left: 0.6rem;
  padding: 0.7rem 1.1rem; border-radius: var(--radius-sm);
  background: var(--btn-bg); color: var(--btn-ink); font-weight: 600;
  transform: translateY(-250%);
}
.skip-link:focus { transform: none; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: var(--header-bg);
  -webkit-backdrop-filter: blur(14px) saturate(1.3);
  backdrop-filter: blur(14px) saturate(1.3);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  max-width: var(--container); margin-inline: auto;
  padding-inline: clamp(1rem, 4vw, 2rem);
  min-height: 64px;
  display: flex; align-items: center; justify-content: space-between; gap: 1rem;
}
.brand { display: inline-flex; align-items: center; gap: 0.6rem; color: var(--text); font-weight: 500; }
.brand:hover { text-decoration: none; }
.brand-logo { width: 34px; height: 34px; flex: none; }
.brand-name strong { color: var(--accent); font-weight: 700; }

.nav ul { display: flex; gap: 0.1rem; flex-wrap: nowrap; }
.nav a {
  display: inline-block; padding: 0.55rem 0.6rem; border-radius: 8px;
  color: var(--muted); font-size: 0.92rem; font-weight: 500; white-space: nowrap;
}
.nav a:hover { color: var(--text); text-decoration: none; background: var(--accent-soft); }
.nav a[aria-current="true"] { color: var(--accent); }

.header-actions { display: flex; align-items: center; gap: 0.4rem; }
.ctrl {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 44px; min-height: 44px; padding: 0 0.6rem;
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  color: var(--muted); font-weight: 700; letter-spacing: 0.02em;
}
.ctrl:hover { color: var(--accent); border-color: var(--accent); }
.ctrl svg { width: 20px; height: 20px; }
[data-theme="dark"] .icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }

/* Burger (mobile only) */
.burger { display: none; position: relative; }
.burger-bar, .burger-bar::before, .burger-bar::after {
  content: ""; display: block; width: 20px; height: 2px;
  background: currentColor; border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease;
}
.burger-bar { position: relative; }
.burger-bar::before, .burger-bar::after { position: absolute; left: 0; }
.burger-bar::before { top: -6px; }
.burger-bar::after { top: 6px; }
.burger[aria-expanded="true"] .burger-bar { transform: rotate(45deg); }
.burger[aria-expanded="true"] .burger-bar::before { transform: rotate(-90deg) translateX(-6px); }
.burger[aria-expanded="true"] .burger-bar::after { opacity: 0; }

/* ---------- Scroll progress ---------- */
.scroll-progress {
  position: fixed; top: 0; left: 0; right: 0; z-index: 60;
  height: 3px; pointer-events: none;
}
.scroll-progress span {
  display: block; height: 100%; width: 100%;
  background: linear-gradient(90deg, var(--accent-2), var(--accent));
  transform: scaleX(0); transform-origin: 0 50%;
}

/* ---------- Hero ---------- */
.hero {
  position: relative; min-height: 100svh;
  display: grid; align-items: center;
  padding: 7rem 0 4rem;
  overflow: hidden;
  isolation: isolate;
}
.hero::before, .hero::after {
  content: ""; position: absolute; z-index: -2; border-radius: 50%;
  filter: blur(70px); pointer-events: none;
}
.hero::before { width: 560px; height: 560px; right: -140px; top: -120px; background: var(--glow); }
.hero::after { width: 460px; height: 460px; left: -160px; bottom: -140px; background: rgba(95, 111, 156, 0.14); }

/* Engineering grid backdrop, faded toward the edges */
.hero-grid {
  position: absolute; inset: 0; z-index: -3; pointer-events: none;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 42px 42px;
  -webkit-mask-image: radial-gradient(ellipse 90% 80% at 50% 40%, #000 35%, transparent 100%);
  mask-image: radial-gradient(ellipse 90% 80% at 50% 40%, #000 35%, transparent 100%);
}

.hero-bg { position: absolute; inset: 0; z-index: -1; pointer-events: none; }
.hero-bg svg { width: 100%; height: 100%; }
.hero-bg path { fill: none; stroke-width: 2; }
.wave-baseline { stroke: var(--border); stroke-dasharray: 3 12; }
.wave-sine {
  stroke: var(--accent); stroke-width: 2.4; opacity: 0.75; stroke-linecap: round;
  stroke-dasharray: 230 150;
  animation: march 8s linear infinite;
}
.wave-pwm {
  stroke: var(--wave2); opacity: 0.5;
  stroke-dasharray: 110 80;
  animation: march 11s linear infinite reverse;
}
@keyframes march { to { stroke-dashoffset: -380; } }
[data-theme="light"] .wave-sine { opacity: 0.55; }
[data-theme="light"] .wave-pwm { opacity: 0.4; }

.hero-kicker {
  display: inline-flex; align-items: center; gap: 0.55rem;
  padding: 0.45rem 0.9rem; border: 1px solid var(--border); border-radius: 999px;
  background: var(--accent-soft); color: var(--text);
  font-size: 0.88rem; font-weight: 500;
}
.pulse-dot {
  width: 9px; height: 9px; flex: none; border-radius: 50%;
  background: var(--accent);
  animation: pulse 2.2s ease-out infinite;
}
@keyframes pulse {
  0% { box-shadow: 0 0 0 0 var(--accent-soft), 0 0 0 0 rgba(251, 191, 36, 0.45); }
  70% { box-shadow: 0 0 0 6px rgba(251, 191, 36, 0), 0 0 0 14px rgba(251, 191, 36, 0); }
  100% { box-shadow: 0 0 0 0 rgba(251, 191, 36, 0), 0 0 0 0 rgba(251, 191, 36, 0); }
}

.hero h1 {
  margin-top: 1.3rem;
  font-size: clamp(2.5rem, 6.5vw + 0.8rem, 4.6rem);
  font-weight: 700; letter-spacing: -0.02em;
}
.hero h1 .accent {
  color: var(--accent);
  background: linear-gradient(100deg, var(--accent) 20%, var(--accent-2) 60%, var(--accent) 100%);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
}
.tagline {
  margin-top: 0.9rem;
  font-size: clamp(1.15rem, 1.6vw + 0.8rem, 1.6rem);
  font-weight: 500; max-width: 46ch;
}
.subline { margin-top: 0.8rem; color: var(--muted); max-width: 62ch; }

.chips { display: flex; flex-wrap: wrap; gap: 0.55rem; margin-top: 1.5rem; }
.chip {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.42rem 0.85rem; border: 1px solid var(--border); border-radius: 999px;
  background: var(--surface); font-size: 0.9rem;
}
.chip-n {
  width: 1.25rem; height: 1.25rem; flex: none;
  display: grid; place-items: center;
  border-radius: 50%; background: var(--accent-soft); color: var(--accent);
  font-size: 0.72rem; font-weight: 700;
}

.cta-row { display: flex; flex-wrap: wrap; gap: 0.7rem; margin-top: 1.8rem; }
.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  min-height: 46px; padding: 0.65rem 1.3rem;
  border-radius: 12px; border: 1px solid transparent;
  font-weight: 600;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); }
.btn svg { width: 18px; height: 18px; flex: none; }
.btn-primary { background: var(--btn-bg); color: var(--btn-ink); }
.btn-primary:hover { box-shadow: 0 8px 26px rgba(245, 158, 11, 0.35); }
.btn-ghost { border-color: var(--border); color: var(--text); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

.hero-meta {
  display: flex; align-items: center; flex-wrap: wrap; gap: 0.45rem;
  margin-top: 1.6rem; color: var(--muted); font-size: 0.92rem;
}
.hero-meta svg { width: 17px; height: 17px; color: var(--accent); }

.cv-alt { margin-top: 0.9rem; color: var(--muted); font-size: 0.88rem; }
.cv-alt a { color: var(--muted); text-decoration: underline; text-underline-offset: 3px; text-decoration-color: var(--border); }
.cv-alt a:hover { color: var(--accent); text-decoration-color: var(--accent); }

.scroll-cue {
  position: absolute; left: 50%; bottom: 1.4rem; transform: translateX(-50%);
  display: grid; place-items: center;
  width: 40px; height: 40px; border-radius: 50%;
  border: 1px solid var(--border); color: var(--muted);
  animation: cue-bob 2.4s ease-in-out infinite;
}
.scroll-cue:hover { color: var(--accent); border-color: var(--accent); }
.scroll-cue svg { width: 18px; height: 18px; }
@keyframes cue-bob {
  0%, 100% { transform: translate(-50%, 0); }
  50% { transform: translate(-50%, 7px); }
}

/* ---------- Tools marquee ---------- */
.tools-strip {
  overflow: hidden; border-block: 1px solid var(--border);
  padding: 0.72rem 0; background: var(--bg-alt);
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent);
  mask-image: linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent);
}
.tools-track {
  display: flex; gap: 2.6rem; width: max-content;
  animation: ticker 36s linear infinite;
  color: var(--muted); font-size: 0.88rem; font-weight: 500; letter-spacing: 0.04em;
}
.tools-track span { display: inline-flex; align-items: center; gap: 2.6rem; white-space: nowrap; }
.tools-track span::after { content: "▸"; color: var(--accent); font-size: 0.72em; }
@keyframes ticker { to { transform: translateX(-50%); } }
.tools-strip:hover .tools-track { animation-play-state: paused; }

/* ---------- Sections ---------- */
.section { padding-block: clamp(4rem, 9vw, 6.5rem); }
.section-alt { background: var(--bg-alt); }

.sec-title {
  display: flex; align-items: baseline; gap: 0.8rem;
  font-size: clamp(1.55rem, 2.6vw + 0.7rem, 2.2rem);
  font-weight: 700; margin-bottom: clamp(2rem, 5vw, 3rem);
}
.sec-n { color: var(--accent); font-size: 0.62em; font-weight: 700; letter-spacing: 0.08em; }
.sec-title::after {
  content: ""; flex: 1; height: 1px; margin-left: 0.4rem;
  background: linear-gradient(to right, var(--border), transparent);
}

/* ---------- About ---------- */
.about-grid { display: grid; grid-template-columns: 1.7fr 1fr; gap: clamp(1.5rem, 4vw, 3rem); align-items: start; }
.about-text p + p { margin-top: 1rem; }
.about-text { color: var(--muted); }
.stat-cards { display: grid; gap: 0.9rem; }
.stat {
  padding: 1.1rem 1.3rem; border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--surface); display: grid; gap: 0.15rem;
  border-left: 3px solid var(--accent);
  transition: transform 0.22s ease, box-shadow 0.22s ease;
}
.stat:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.stat strong { font-size: 1.7rem; color: var(--accent); font-weight: 700; }
.stat strong small { font-size: 0.55em; color: var(--muted); font-weight: 500; }
.stat span { color: var(--muted); font-size: 0.9rem; }

/* ---------- Timeline ---------- */
.timeline { position: relative; display: grid; gap: 1.4rem; }
.timeline::before {
  content: ""; position: absolute; top: 6px; bottom: 6px; left: 170px;
  width: 2px; background: linear-gradient(var(--accent), var(--border));
  opacity: 0.55;
}
.tl-item { display: grid; grid-template-columns: 148px 1fr; gap: 2.6rem; position: relative; }
.tl-item::before {
  content: ""; position: absolute; left: 165px; top: 8px;
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft);
}
.tl-date { color: var(--accent); font-weight: 600; font-size: 0.88rem; text-align: right; padding-top: 2px; }
.tl-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.2rem 1.4rem;
  transition: transform 0.22s ease, border-color 0.22s ease, box-shadow 0.22s ease;
}
.tl-card:hover { transform: translateY(-3px); border-color: var(--accent); box-shadow: var(--shadow); }
.tl-card h3 { font-size: 1.08rem; }
.tl-org { color: var(--accent); font-size: 0.92rem; font-weight: 500; margin-top: 0.2rem; }
.tl-note { color: var(--muted); font-size: 0.95rem; margin-top: 0.45rem; }
.badge {
  display: inline-block; padding: 0.14rem 0.65rem; border-radius: 999px;
  background: var(--accent-soft); color: var(--accent);
  font-size: 0.8rem; font-weight: 600;
}
.tl-list { display: grid; gap: 0.4rem; margin-top: 0.6rem; color: var(--muted); font-size: 0.95rem; }
.tl-list li { padding-left: 1.1rem; position: relative; }
.tl-list li::before { content: "▸"; position: absolute; left: 0; color: var(--accent); }

.tags { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 0.85rem; }
.tags li {
  padding: 0.16rem 0.62rem; border: 1px solid var(--border); border-radius: 999px;
  font-size: 0.78rem; color: var(--muted);
}
.tags-lg li { font-size: 0.86rem; padding: 0.3rem 0.75rem; }

/* ---------- Projects ---------- */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(270px, 1fr)); gap: 1.2rem; }
.card {
  position: relative; overflow: hidden;
  display: flex; flex-direction: column; gap: 0.55rem;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.4rem;
  transition: transform 0.22s ease, border-color 0.22s ease, box-shadow 0.22s ease;
}
.card:hover { transform: translateY(-4px); border-color: var(--accent); box-shadow: var(--shadow); }
.card::after {
  content: ""; position: absolute; inset: 0; z-index: 0; pointer-events: none;
  background: radial-gradient(220px circle at var(--mx, 50%) var(--my, 0%), var(--spot), transparent 70%);
  opacity: 0; transition: opacity 0.3s ease;
}
.card:hover::after { opacity: 1; }
.card > * { position: relative; z-index: 1; }
.card-ico {
  display: grid; place-items: center;
  width: 38px; height: 38px; border-radius: 11px;
  background: var(--accent-soft); color: var(--accent);
  border: 1px solid var(--border);
}
.card-ico svg { width: 22px; height: 22px; }
.card h3 { font-size: 1.12rem; }
.card p { color: var(--muted); font-size: 0.95rem; }
.card-top { display: flex; align-items: center; justify-content: space-between; gap: 0.6rem; min-height: 1.6rem; }
.card-meta { color: var(--muted); font-size: 0.8rem; }
.card-flagship { border-left: 3px solid var(--accent); }
.flag-badge {
  display: inline-block; padding: 0.18rem 0.65rem; border-radius: 999px;
  background: var(--btn-bg); color: var(--btn-ink);
  font-size: 0.72rem; font-weight: 700; letter-spacing: 0.05em; text-transform: uppercase;
}
/* Documents & files attached to a project */
.card-files {
  margin-top: auto; padding-top: 0.9rem;
  display: flex; flex-wrap: wrap; align-items: center; gap: 0.45rem;
  border-top: 1px dashed var(--border);
}
.files-label {
  flex-basis: 100%;
  font-size: 0.7rem; font-weight: 700; letter-spacing: 0.09em; text-transform: uppercase;
  color: var(--muted);
  display: inline-flex; align-items: center; gap: 0.45rem;
}
.files-label::before {
  content: ""; width: 7px; height: 7px; flex: none;
  background: var(--accent); transform: rotate(45deg); border-radius: 1.5px;
}
.file-btn {
  display: inline-flex; align-items: center; gap: 0.45rem;
  max-width: 100%;
  padding: 0.42rem 0.7rem;
  border: 1px solid var(--border); border-radius: 10px;
  background: var(--bg-alt);
  color: var(--text); font-size: 0.84rem; font-weight: 500; line-height: 1.3;
  transition: border-color 0.2s ease, color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}
.file-btn > span:first-of-type { overflow-wrap: anywhere; }
.file-btn svg { width: 15px; height: 15px; flex: none; color: var(--accent); }
a.file-btn:hover {
  text-decoration: none; border-color: var(--accent); color: var(--accent);
  transform: translateY(-2px); box-shadow: 0 6px 18px var(--glow);
}
.file-ext {
  flex: none;
  padding: 0.04rem 0.38rem; border: 1px solid var(--accent); border-radius: 6px;
  color: var(--accent); font-size: 0.66rem; font-weight: 700; letter-spacing: 0.05em;
}
.file-btn.is-soon { opacity: 0.55; }
.file-btn.is-soon .file-ext { border-style: dashed; }
.tl-card .file-btn { margin-top: 0.85rem; }

@media (min-width: 860px) {
  .card-flagship { grid-column: span 2; }
}

/* ---------- Skills ---------- */
.domains-hint { color: var(--muted); font-size: 0.86rem; margin-bottom: 0.9rem; }
.skill-domains {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  align-items: start; gap: 0.7rem; margin-bottom: 1.6rem;
}
.skill-domains > li:not(.sd) {
  display: flex; align-items: center; gap: 0.65rem;
  padding: 0.85rem 1rem; border: 1px solid var(--border); border-radius: 12px;
  background: var(--surface); font-size: 0.94rem;
}
.skill-domains > li:not(.sd)::before {
  content: ""; width: 8px; height: 8px; flex: none;
  background: var(--accent); transform: rotate(45deg); border-radius: 2px;
}

/* Expandable skill domains: hover-to-peek (pointer devices) + click/keyboard to pin open */
.sd-toggle {
  display: flex; width: 100%; align-items: center; gap: 0.65rem;
  padding: 0.85rem 1rem; border: 1px solid var(--border); border-radius: 12px;
  background: var(--surface); color: var(--text); font: inherit; font-size: 0.94rem;
  text-align: left; cursor: pointer;
  transition: border-color 0.2s ease;
}
.sd-toggle::before {
  content: ""; width: 8px; height: 8px; flex: none;
  background: var(--accent); transform: rotate(45deg); border-radius: 2px;
}
.sd-toggle span { flex: 1; }
.sd-chevron { width: 18px; height: 18px; flex: none; color: var(--muted); transition: transform 0.25s ease, color 0.2s ease; }
.sd-toggle:hover, .sd-toggle:focus-visible { border-color: var(--accent); }
.sd-toggle:hover .sd-chevron, .sd-toggle:focus-visible .sd-chevron { color: var(--accent); }

.sd-panel {
  max-height: 0; overflow: hidden; opacity: 0; margin-top: 0;
  transition: max-height 0.35s ease, opacity 0.25s ease, margin-top 0.35s ease;
}
.sd-panel p { color: var(--muted); font-size: 0.87rem; line-height: 1.55; padding: 0 0.15rem; }
.sd-panel .tags { margin-top: 0.6rem; padding: 0 0.15rem; }

@media (hover: hover) and (pointer: fine) {
  .sd:hover .sd-panel, .sd:focus-within .sd-panel { max-height: 20rem; opacity: 1; margin-top: 0.7rem; }
  .sd:hover .sd-chevron, .sd:focus-within .sd-chevron { transform: rotate(180deg); }
}
.sd.is-open .sd-panel { max-height: 20rem; opacity: 1; margin-top: 0.7rem; }
.sd.is-open .sd-chevron { transform: rotate(180deg); }
.skill-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1.2rem; }
.skill-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.4rem;
}
.skill-card h3 { font-size: 1.05rem; margin-bottom: 0.9rem; position: relative; padding-bottom: 0.55rem; }
.skill-card h3::after {
  content: ""; position: absolute; left: 0; bottom: 0;
  width: 34px; height: 3px; border-radius: 2px; background: var(--accent);
}
.lang-list { display: grid; gap: 0.5rem; }
.lang-list li {
  display: flex; justify-content: space-between; align-items: center; gap: 1rem;
  padding-bottom: 0.5rem; border-bottom: 1px dashed var(--border);
  font-size: 0.95rem;
}
.lvl { color: var(--accent); font-weight: 700; }
.cert { margin-top: 1rem; color: var(--muted); font-size: 0.9rem; }
.assoc-list { display: grid; gap: 0.5rem; color: var(--muted); font-size: 0.95rem; }
.assoc-list li { padding-left: 1.1rem; position: relative; }
.assoc-list li::before { content: "▸"; position: absolute; left: 0; color: var(--accent); }

/* ---------- Documents ---------- */
.docs-intro { color: var(--muted); margin-bottom: 1.6rem; max-width: 60ch; }
.doc-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1rem; }
.doc-card {
  display: flex; align-items: center; gap: 0.9rem;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.1rem 1.2rem; color: var(--text);
  transition: transform 0.22s ease, border-color 0.22s ease, box-shadow 0.22s ease;
}
.doc-card:hover { text-decoration: none; transform: translateY(-3px); border-color: var(--accent); box-shadow: var(--shadow); }
.doc-ico {
  display: grid; place-items: center; flex: none;
  width: 42px; height: 42px; border-radius: 11px;
  background: var(--accent-soft); color: var(--accent);
  border: 1px solid var(--border);
}
.doc-ico svg { width: 22px; height: 22px; }
.doc-body { display: flex; flex-direction: column; gap: 0.25rem; flex: 1; min-width: 0; }
.doc-body strong { font-size: 0.98rem; line-height: 1.3; }
.doc-body span { color: var(--muted); font-size: 0.86rem; line-height: 1.4; }
.doc-card .file-ext { flex: none; }

/* ---------- Contact ---------- */
.contact-wrap { text-align: center; max-width: 720px; }
.contact-wrap .sec-title { justify-content: center; }
.contact-wrap .sec-title::after { display: none; }
.contact-pitch { color: var(--muted); font-size: 1.08rem; max-width: 54ch; margin-inline: auto; }
.contact-wrap .cta-row { justify-content: center; margin-top: 1.6rem; }
.contact-email { margin-top: 1.4rem; font-size: 1.05rem; overflow-wrap: anywhere; }
.contact-email a { font-weight: 600; }
.contact-wrap .hero-meta { justify-content: center; margin-top: 0.8rem; }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--border); padding: 1.6rem 0; }
.footer-inner {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between;
  gap: 1rem; color: var(--muted); font-size: 0.9rem;
}
.footer-links { display: flex; flex-wrap: wrap; gap: 1.1rem; }
.footer-links a { color: var(--muted); }
.footer-links a:hover { color: var(--accent); }
.footer-actions { display: flex; gap: 0.4rem; }

/* ---------- Scroll reveal ---------- */
.js .reveal { opacity: 0; transform: translateY(18px); transition: opacity 0.6s ease, transform 0.6s ease; transition-delay: var(--rd, 0s); }
.js .reveal.in { opacity: 1; transform: none; }

/* ---------- Back to top ---------- */
.to-top {
  position: fixed; right: 1.1rem; bottom: 1.1rem; z-index: 45;
  display: grid; place-items: center;
  width: 46px; height: 46px; border-radius: 50%;
  background: var(--surface); border: 1px solid var(--border); color: var(--muted);
  box-shadow: var(--shadow);
  opacity: 0; visibility: hidden; transform: translateY(10px);
  transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s, color 0.2s ease, border-color 0.2s ease;
}
.to-top.show { opacity: 1; visibility: visible; transform: none; }
.to-top:hover { color: var(--accent); border-color: var(--accent); }
.to-top svg { width: 20px; height: 20px; }

/* ---------- Header nav collapse (own breakpoint: 8 nav items need more room than the general mobile layout) ---------- */
@media (max-width: 900px) {
  .burger { display: inline-flex; }
  .nav {
    position: fixed; z-index: 49; top: 64px; left: 0; right: 0;
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
    padding: 0.6rem 1rem 1rem;
    opacity: 0; visibility: hidden; transform: translateY(-10px);
    transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s;
  }
  .nav.open { opacity: 1; visibility: visible; transform: none; }
  .nav ul { flex-direction: column; gap: 0.1rem; }
  .nav a { display: block; padding: 0.85rem 0.9rem; font-size: 1.02rem; }
}

/* ---------- Mobile ---------- */
@media (max-width: 767px) {
  .timeline::before { left: 5px; }
  .tl-item { grid-template-columns: 1fr; gap: 0.5rem; padding-left: 1.6rem; }
  .tl-item::before { left: 0; top: 6px; }
  .tl-ico { left: -5px; top: 0; }
  .tl-date { text-align: left; }
  .about-grid { grid-template-columns: 1fr; }
  .stat-cards { grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); }
  .hero { padding-top: 6rem; }
  .scroll-cue { display: none; }
}
@media (max-height: 720px) {
  .scroll-cue { display: none; }
}

/* ---------- Engineering graphics layer ---------- */

/* PCB-trace pattern on alternate sections */
.section-alt { background-image: var(--pcb); background-size: 180px 180px; }

/* Hero: faint buck-converter schematic in the backdrop */
.hero-schematic {
  position: absolute; z-index: -1; pointer-events: none;
  right: clamp(0.5rem, 4vw, 4rem); bottom: clamp(2rem, 7vh, 5rem);
  width: min(430px, 36vw);
  color: var(--text); opacity: 0.15;
}
[data-theme="light"] .hero-schematic { opacity: 0.11; }
.hero-schematic svg { width: 100%; height: auto; display: block; }
.hero-schematic path, .hero-schematic circle {
  stroke: currentColor; fill: none;
  stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round;
}
.hero-schematic circle { fill: currentColor; stroke: none; }
.hero-schematic .sch-a { stroke: var(--accent); }
.hero-schematic circle.sch-a { fill: var(--accent); stroke: none; }
@media (max-width: 900px) { .hero-schematic { display: none; } }

/* Hero grid: brightens around the cursor (precise pointers only) */
.hero-grid::after {
  content: ""; position: absolute; inset: 0;
  background-image:
    linear-gradient(var(--grid-line-hot) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line-hot) 1px, transparent 1px);
  background-size: 42px 42px;
  -webkit-mask-image: radial-gradient(240px circle at var(--hx, -999px) var(--hy, -999px), #000 30%, transparent 100%);
  mask-image: radial-gradient(240px circle at var(--hx, -999px) var(--hy, -999px), #000 30%, transparent 100%);
}

/* Project card mini-diagrams */
.card-diagram {
  margin: -1.4rem -1.4rem 0.4rem;
  padding: 0.55rem 0.8rem;
  background: var(--bg-alt);
  background-image: var(--pcb); background-size: 180px 180px;
  border-bottom: 1px solid var(--border);
}
.card { min-width: 0; } /* the diagram SVGs' intrinsic width must never size the grid track */
.card-diagram svg { width: 100%; height: 84px; display: block; }
@media (min-width: 860px) {
  .card-flagship .card-diagram svg { height: 132px; }
}
.dga { stroke: var(--accent); fill: none; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.dgb { stroke: var(--wave2); fill: none; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.dgm { stroke: var(--border); fill: none; stroke-width: 1.4; stroke-linecap: round; stroke-linejoin: round; }
.dgfa { fill: var(--accent); }
.dgt {
  fill: var(--muted);
  font-family: var(--font); font-size: 11px; font-weight: 600;
  text-anchor: middle;
}
.dgt-a { fill: var(--accent); }
.dg-flow { stroke-dasharray: 2 7; animation: dg-flow 6s linear infinite; }
@keyframes dg-flow { to { stroke-dashoffset: -180; } }
.dg-rot {
  transform-box: view-box; transform-origin: 50% 50%;
  animation: dg-spin 14s linear infinite;
}
@keyframes dg-spin { to { transform: rotate(360deg); } }
.dg-track { stroke: var(--muted); fill: none; stroke-width: 11; stroke-linecap: round; opacity: 0.28; }
.dg-race { stroke-width: 2.4; stroke-dasharray: 2 10; animation: dg-flow 5s linear infinite; }

/* Timeline: icon medallions replace the plain dots */
.tl-item::before { display: none; }
.tl-ico {
  position: absolute; left: 160px; top: 0;
  width: 22px; height: 22px; border-radius: 50%;
  display: grid; place-items: center;
  background: var(--surface); border: 1.5px solid var(--accent);
  color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
}
.tl-ico svg { width: 13px; height: 13px; }
@media (prefers-reduced-motion: no-preference) {
  .tl-ico { animation: tl-pulse 3.2s ease-out infinite; }
}
@keyframes tl-pulse {
  0%, 100% { box-shadow: 0 0 0 4px var(--accent-soft); }
  50% { box-shadow: 0 0 0 8px rgba(251, 191, 36, 0.05); }
}

/* Skill domains: icons replace the diamond bullets */
.skill-domains > li:not(.sd)::before, .sd-toggle::before { display: none; }
.sd-ico { width: 18px; height: 18px; flex: none; color: var(--accent); }

/* Stats: steady digits during count-up */
.stat strong { font-variant-numeric: tabular-nums; }

/* Micro-interactions */
.btn-primary { position: relative; overflow: hidden; }
.btn-primary::after {
  content: ""; position: absolute; top: 0; bottom: 0; left: -70%; width: 45%;
  background: linear-gradient(100deg, transparent, rgba(255, 255, 255, 0.38), transparent);
  transform: skewX(-20deg);
  transition: left 0.55s ease;
  pointer-events: none;
}
.btn-primary:hover::after { left: 125%; }
.btn-primary > * { position: relative; }
.card-ico, .doc-ico { transition: transform 0.25s ease; }
.card:hover .card-ico { transform: rotate(-6deg) scale(1.07); }
.doc-card:hover .doc-ico { transform: rotate(-6deg) scale(1.07); }
.file-btn svg { transition: transform 0.2s ease; }
a.file-btn:hover svg { transform: translateY(-1.5px); }
.brand:hover .brand-logo path {
  stroke-dasharray: 46 18;
  animation: brand-march 1.2s linear infinite;
}
@keyframes brand-march { to { stroke-dashoffset: -64; } }

/* Footer wave divider */
.footer-wave { overflow: hidden; margin-top: -1rem; }
.footer-wave svg { width: 100%; height: 64px; display: block; opacity: 0.55; }
.footer-wave path { fill: none; stroke-width: 2; }

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .js .reveal { opacity: 1; transform: none; }
  .wave-sine, .wave-pwm { animation: none; }
  .pulse-dot { animation: none; }
  .tools-track { animation: none; }
  .scroll-cue { animation: none; }
  .card::after { display: none; }
  .dg-flow, .dg-rot, .dg-race { animation: none; }
  .tl-item::before, .tl-ico { animation: none; }
  .hero-grid::after { display: none; }
}