/* =========================================================================
   Saiful Iqbal — Portfolio v3: experience layer
   Motion, depth and interaction on top of css/main.css.

   Rules of this file:
   - Every animation is gated behind `.motion` on <html> (set in the head
     script only when the visitor has NOT asked for reduced motion).
   - Nothing here is needed to read the page: without JS or motion the
     content is fully visible and static.
   - Only transform / opacity / clip-path / background-size are animated.
   ========================================================================= */

:root {
  --ease-out: cubic-bezier(.16, 1, .3, 1);
  --ease-in-out: cubic-bezier(.65, 0, .35, 1);
  --glass: color-mix(in srgb, var(--paper) 62%, transparent);
  --glow: color-mix(in srgb, var(--accent) 26%, transparent);
  --d: 0ms; /* extra delay while the intro screen is up */
}
.intro { --d: 1350ms; }

/* ---------- 1. Intro screen (first visit of a session, CSS-only) ---------- */
@property --n { syntax: "<integer>"; initial-value: 0; inherits: false; }

.intro-screen { display: none; }
.intro .intro-screen {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: grid;
  place-items: center;
  background: var(--ink);
  color: var(--paper);
  animation: intro-out .7s var(--ease-in-out) 1.15s forwards;
}
.intro-inner {
  width: min(420px, 78vw);
  display: grid;
  gap: var(--s-4);
}
.intro-row { display: flex; justify-content: space-between; align-items: baseline; }
.intro-name { font-weight: 600; font-size: 1.125rem; letter-spacing: -0.01em; }
.intro-name span { color: var(--accent); }
.intro-count {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: .06em;
  counter-reset: n var(--n);
  animation: intro-count 1s var(--ease-in-out) forwards;
}
.intro-count::after { content: counter(n, decimal-leading-zero) "%"; }
.intro-bar { height: 1px; background: color-mix(in srgb, var(--paper) 25%, transparent); overflow: hidden; }
.intro-bar i {
  display: block;
  height: 100%;
  background: var(--accent);
  transform-origin: left;
  transform: scaleX(0);
  animation: intro-bar 1s var(--ease-in-out) forwards;
}
.intro-meta { font-family: var(--font-mono); font-size: 0.6875rem; letter-spacing: .08em; text-transform: uppercase; opacity: .6; }

@keyframes intro-count { to { --n: 100; } }
@keyframes intro-bar { to { transform: scaleX(1); } }
@keyframes intro-out {
  from { clip-path: inset(0 0 0 0); }
  to { clip-path: inset(0 0 100% 0); visibility: hidden; }
}

/* ---------- 2. Atmosphere: grain + light ---------- */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 90;
  pointer-events: none;
  opacity: .055;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}
:root[data-theme="dark"] body::after { mix-blend-mode: screen; opacity: .05; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) body::after { mix-blend-mode: screen; opacity: .05; }
}

.glow {
  position: absolute;
  width: 46vmax;
  aspect-ratio: 1;
  border-radius: 50%;
  background: radial-gradient(circle, var(--glow), transparent 62%);
  filter: blur(20px);
  pointer-events: none;
  z-index: 0;
}
.glow--hero { top: -18vmax; right: -14vmax; }
.glow--contact {
  width: 38vmax;
  left: calc(var(--gx, 70%) - 19vmax);
  top: calc(var(--gy, 30%) - 19vmax);
  opacity: .9;
  transition: left .9s var(--ease-out), top .9s var(--ease-out);
}

/* ---------- 3. Scroll progress + header ---------- */
.scroll-progress {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 2px;
  z-index: 60;
  background: var(--accent);
  transform-origin: left;
  transform: scaleX(var(--p, 0));
  pointer-events: none;
}
.site-header { transition: transform .5s var(--ease-out); view-transition-name: site-header; }
.site-header.is-hidden { transform: translateY(-101%); }

.nav-list a { position: relative; }
@media (min-width: 900px) {
  .nav-list a::after {
    content: "";
    position: absolute;
    left: 10px; right: 10px; bottom: 4px;
    height: 1px;
    background: currentColor;
    transform: scaleX(0);
    transform-origin: right;
    transition: transform .4s var(--ease-out);
  }
  .nav-list a:hover { background: transparent; }
  .nav-list a:hover::after { transform: scaleX(1); transform-origin: left; }
  .nav-list a[aria-current]::after { display: none; }
}

/* ---------- 4. Cursor follower (fine pointers only; native cursor stays) ---------- */
.cursor {
  position: fixed;
  top: 0; left: 0;
  z-index: 150;
  width: 34px; height: 34px;
  margin: -17px 0 0 -17px;
  border: 1px solid var(--accent);
  border-radius: 50%;
  pointer-events: none;
  opacity: 0;
  display: grid;
  place-items: center;
  font: 500 0.625rem/1 var(--font-mono);
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--accent-ink);
  transition: opacity .3s ease, width .35s var(--ease-out), height .35s var(--ease-out),
              margin .35s var(--ease-out), background-color .3s ease, border-color .3s ease;
  will-change: transform;
}
.cursor.is-on { opacity: 1; }
.cursor.is-hover { width: 54px; height: 54px; margin: -27px 0 0 -27px; background: color-mix(in srgb, var(--accent) 14%, transparent); }
.cursor.is-label { width: 78px; height: 78px; margin: -39px 0 0 -39px; background: var(--accent); }
.cursor.is-down { width: 24px; height: 24px; margin: -12px 0 0 -12px; }
.cursor.is-text { opacity: 0; }

/* ---------- 5. Reveal on scroll ---------- */
.reveal-ready .rv { opacity: 0; transform: translateY(22px); }
.reveal-ready .rv.is-in {
  opacity: 1;
  transform: none;
  transition: opacity .8s var(--ease-out), transform 1s var(--ease-out);
}

/* Words that rise out of a mask */
.w { display: inline-block; overflow: hidden; vertical-align: top; padding: .1em 0 .14em; margin: -.1em 0 -.14em; }
.wi { display: inline-block; transform: translateY(115%); will-change: transform; }
.is-in > .w > .wi, .is-in .mark > .w > .wi {
  transform: none;
  transition: transform 1s var(--ease-out);
  transition-delay: calc(var(--i, 0) * 42ms + var(--d));
}
/* Headlines wait (invisibly) for the splitter; a failsafe shows them if JS never runs */
.motion .hero h1:not(.is-split),
.motion .cs-hero h1:not(.is-split),
.motion .not-found h1:not(.is-split) { opacity: 0; animation: failsafe 0s 3s forwards; }
@keyframes failsafe { to { opacity: 1; } }

/* The accent underline draws itself after the words have landed */
.motion .hero h1 .mark { background-size: 0 0.09em; }
.motion .hero h1.is-in .mark { background-size: 100% 0.09em; transition: background-size 1s var(--ease-in-out) calc(700ms + var(--d)); }

/* Hero pieces rise in sequence (pure CSS) */
.motion .hero-seq {
  opacity: 0;
  animation: rise 1s var(--ease-out) forwards;
  animation-delay: calc(var(--d) + 420ms + var(--s, 0) * 110ms);
}
@keyframes rise { from { opacity: 0; transform: translateY(26px); } to { opacity: 1; transform: none; } }

/* Lines that draw themselves */
.motion .reveal-ready .section { border-top-color: transparent; position: relative; }
.motion .reveal-ready .section::before {
  content: "";
  position: absolute;
  top: -1px; left: 0; right: 0;
  height: 1px;
  background: var(--rule);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 1.4s var(--ease-in-out);
}
.motion .reveal-ready .section.is-seen::before { transform: scaleX(1); }

/* ---------- 6. Hero ---------- */
.hero { position: relative; overflow: hidden; isolation: isolate; }
.hero > .container { position: relative; z-index: 2; }
.hero-gl {
  position: absolute;
  inset: 0 0 auto 0;
  width: 100%;
  /* Never taller than about one screen, so tall mobile heroes don't stretch it */
  height: min(100%, 105svh);
  z-index: 1;
  pointer-events: none;
  opacity: 0;
  transition: opacity 1.6s ease calc(var(--d) + 200ms);
  -webkit-mask-image: linear-gradient(to bottom, transparent 0%, #000 34%, #000 82%, transparent 100%);
          mask-image: linear-gradient(to bottom, transparent 0%, #000 34%, #000 82%, transparent 100%);
}
.hero-gl.is-live { opacity: 1; }

.hero-card {
  padding: var(--s-5);
  background: var(--glass);
  border: 1px solid color-mix(in srgb, var(--ink) 10%, transparent);
  border-radius: 6px;
  -webkit-backdrop-filter: blur(14px) saturate(1.3);
          backdrop-filter: blur(14px) saturate(1.3);
}
.hero-card .record { border-top-color: color-mix(in srgb, var(--ink) 30%, transparent); }
.hero-card .record dt, .hero-card .record dd { border-bottom-color: color-mix(in srgb, var(--ink) 10%, transparent); }
.hero-card .record dt:nth-last-of-type(1), .hero-card .record dd:last-of-type { border-bottom: 0; }

.proof { position: relative; }
.proof .figure { font-variant-numeric: tabular-nums; }
.proof a { transition: transform .5s var(--ease-out); }
.motion .proof a:hover { transform: translateY(-4px); }

.scroll-cue {
  display: none;
  align-items: center;
  gap: var(--s-3);
  margin-top: var(--s-6);
}
.scroll-cue i { width: 44px; height: 1px; background: var(--muted); position: relative; overflow: hidden; }
.motion .scroll-cue i::after {
  content: "";
  position: absolute; inset: 0;
  background: var(--accent);
  animation: cue 2.2s var(--ease-in-out) infinite;
}
@keyframes cue { 0% { transform: translateX(-100%); } 60%, 100% { transform: translateX(100%); } }
@media (min-width: 1000px) { .scroll-cue { display: flex; } }

/* ---------- 7. Marquee band ---------- */
.marquee {
  overflow: hidden;
  border-top: 1px solid var(--rule);
  padding-block: var(--s-5);
  white-space: nowrap;
  user-select: none;
}
.marquee-track { display: inline-flex; gap: 0; will-change: transform; }
.motion .marquee-track { animation: marquee 38s linear infinite; }
.marquee:hover .marquee-track { animation-play-state: paused; }
.marquee-group { display: inline-flex; align-items: center; }
.marquee-group span {
  font-size: clamp(1.75rem, 4.6vw, 3.75rem);
  font-weight: 500;
  letter-spacing: -0.03em;
  color: var(--ink);
  padding-inline: clamp(16px, 2.4vw, 36px);
}
.marquee-group span:nth-child(4n + 3) {
  color: transparent;
  -webkit-text-stroke: 1px var(--ink);
}
.marquee-group i {
  width: 10px; height: 10px;
  background: var(--accent);
  border-radius: 50%;
  flex-shrink: 0;
}
@keyframes marquee { to { transform: translateX(-50%); } }

/* ---------- 8. Featured work cards: tilt, spotlight, living diagrams ---------- */
.case-card { perspective: 1200px; }
.case-tilt {
  position: relative;
  transform: rotateX(var(--rx, 0deg)) rotateY(var(--ry, 0deg));
  transform-style: preserve-3d;
  transition: transform .7s var(--ease-out), border-color .4s ease, box-shadow .6s ease;
}
.case-tilt.is-tilting { transition: transform .12s linear, border-color .4s ease, box-shadow .6s ease; }
.case-tilt::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  pointer-events: none;
  background: radial-gradient(520px circle at var(--mx, 50%) var(--my, 50%), color-mix(in srgb, var(--accent) 16%, transparent), transparent 55%);
  opacity: 0;
  transition: opacity .5s ease;
}
.case-card:hover .case-tilt::after { opacity: 1; }
.case-card:hover .case-tilt {
  border-color: color-mix(in srgb, var(--accent) 55%, var(--rule));
  box-shadow: 0 30px 60px -30px color-mix(in srgb, var(--ink) 35%, transparent);
}
.motion .case-visual > * { transform: translateZ(40px); }
.motion .case-body { transform: translateZ(20px); }

/* Diagram animations */
.motion .m-sweep { transform-box: view-box; transform-origin: 200px 120px; animation: spin 5s linear infinite; }
.motion .m-blip { animation: blip 5s ease-out infinite; }
.motion .m-blip--2 { animation-delay: 1.9s; }
.motion .m-blip--3 { animation-delay: 3.3s; }
.motion .m-node rect { animation: node 4.8s ease-in-out infinite; animation-delay: calc(var(--k) * 1.2s); }
.motion .m-packet { animation: packet 4.8s linear infinite; }
.motion .m-radius { transform-box: fill-box; transform-origin: center; animation: radius 3.2s ease-out infinite; }
.motion .m-dash { animation: dash 14s linear infinite; }
.motion .browser img { transition: transform 1.2s var(--ease-out); }
.motion .case-card:hover .browser img { transform: scale(1.06); }

@keyframes spin { to { transform: rotate(360deg); } }
@keyframes blip { 0%, 12% { opacity: 1; r: 5px; } 60%, 100% { opacity: .25; r: 3px; } }
@keyframes node { 0%, 20%, 100% { stroke: var(--rule); } 6%, 14% { stroke: var(--accent); } }
@keyframes packet { from { transform: translateX(0); } to { transform: translateX(292px); } }
@keyframes radius { from { transform: scale(.3); opacity: .9; } to { transform: scale(1); opacity: 0; } }
@keyframes dash { to { stroke-dashoffset: -400; } }

/* Diagrams only run while their card is on screen */
.case-card:not(.is-visible) .case-visual * { animation-play-state: paused !important; }

/* ---------- 9. Project index + lists: micro-interactions ---------- */
.project-row summary { position: relative; transition: padding-left .5s var(--ease-out); }
.project-row summary::before {
  content: "";
  position: absolute;
  left: 0; top: 50%;
  width: 0; height: 1px;
  background: var(--accent);
  transition: width .5s var(--ease-out);
}
@media (hover: hover) and (min-width: 640px) {
  .motion .project-row summary:hover { padding-left: 28px; }
  .motion .project-row summary:hover::before { width: 18px; }
}
.project-row { interpolate-size: allow-keywords; }
.motion .project-row::details-content {
  block-size: 0;
  overflow: hidden;
  transition: block-size .6s var(--ease-out), content-visibility .6s allow-discrete;
}
.motion .project-row[open]::details-content { block-size: auto; }

.evidence tbody tr, .cred-table tbody tr, .plain-list li, .link-list a { transition: background-color .3s ease, padding .5s var(--ease-out); }
@media (hover: hover) {
  .evidence tbody tr:hover, .cred-table tbody tr:hover { background: color-mix(in srgb, var(--accent) 6%, transparent); }
  .motion .link-list a:hover { padding-left: 10px; }
}
.tag { transition: border-color .3s ease, color .3s ease, transform .4s var(--ease-out); }
@media (hover: hover) {
  .motion .tag:hover { border-color: var(--accent); color: var(--ink); transform: translateY(-2px); }
}

/* Timeline spine that fills as you scroll */
.timeline { position: relative; }
@media (min-width: 900px) {
  .motion .timeline::before, .motion .timeline::after {
    content: "";
    position: absolute;
    left: 156px; top: 0; bottom: 0;
    width: 1px;
    background: var(--rule);
  }
  .motion .timeline::after {
    background: var(--accent);
    transform-origin: top;
    transform: scaleY(var(--tp, 0));
  }
}

/* Photos: colour returns on hover, slight lift */
.photos img { transition: filter .6s ease, transform .9s var(--ease-out); }
@media (hover: hover) {
  .motion .photos figure:hover img { filter: saturate(1.1); transform: scale(1.03) rotate(-.6deg); }
}
.photos figure { overflow: hidden; }
.photos figcaption { background: var(--paper); position: relative; }

/* ---------- 10. Contact ---------- */
#contact { position: relative; overflow: hidden; isolation: isolate; }
#contact > .container { position: relative; z-index: 1; }
.contact-email a { background-image: linear-gradient(var(--accent), var(--accent)); background-repeat: no-repeat; background-position: 0 100%; background-size: 100% 2px; border-bottom: 0; transition: background-size .6s var(--ease-out), color .4s ease; padding-bottom: 4px; }
@media (hover: hover) {
  .motion .contact-email a:hover { background-size: 100% 100%; color: var(--accent-ink); }
}
.field input, .field textarea { transition: border-color .3s ease, box-shadow .4s ease, background-color .3s ease; }
.field input:focus, .field textarea:focus { box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 16%, transparent); }

/* ---------- 11. Footer wordmark ---------- */
.wordmark {
  display: block;
  font-size: clamp(3.4rem, 17.5vw, 17rem);
  font-weight: 600;
  letter-spacing: -0.055em;
  line-height: .86;
  white-space: nowrap;
  color: transparent;
  -webkit-text-stroke: 1px color-mix(in srgb, var(--ink) 55%, transparent);
  background: linear-gradient(var(--ink), var(--ink)) no-repeat 0 0 / 0% 100%;
  -webkit-background-clip: text;
          background-clip: text;
  transition: background-size 1.6s var(--ease-in-out);
  user-select: none;
  /* room for descenders, so the fill covers the whole glyph */
  padding-bottom: 0.2em;
  margin-bottom: -0.12em;
}
.wordmark span { color: var(--accent); -webkit-text-fill-color: var(--accent); -webkit-text-stroke-color: var(--accent); }
.wordmark.is-in, .no-js .wordmark, :root:not(.motion) .wordmark { background-size: 100% 100%; }

/* ---------- 12. Page transitions (cross-document View Transitions) ---------- */
@view-transition { navigation: auto; }
.vt-veritas { view-transition-name: case-veritas; }
.vt-hrsb { view-transition-name: case-hrsb; }
.vt-roadsense { view-transition-name: case-roadsense; }

::view-transition-old(root) { animation: vt-out .35s var(--ease-in-out) both; }
::view-transition-new(root) { animation: vt-in .6s var(--ease-out) both; }
@keyframes vt-out { to { opacity: 0; transform: translateY(-14px); } }
@keyframes vt-in { from { opacity: 0; transform: translateY(22px); } }
::view-transition-group(case-veritas),
::view-transition-group(case-hrsb),
::view-transition-group(case-roadsense) { animation-duration: .65s; animation-timing-function: var(--ease-out); }

/* ---------- 13. Respect reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  @view-transition { navigation: none; }
  .intro-screen, .cursor, .scroll-progress { display: none !important; }
  .rv, .wi, .hero-seq { opacity: 1 !important; transform: none !important; animation: none !important; }
  .hero-gl { transition: none; }
}

@media print {
  .intro-screen, .cursor, .scroll-progress, .hero-gl, .glow, .marquee { display: none !important; }
}