/*
  ═══════════════════════════════════════════
  CHERYL KWAN — SHARED STYLES
  styles.css

  Shared across: index.html, all case-study pages
  ═══════════════════════════════════════════
*/

/* ── CROSS-PAGE TRANSITIONS ── */
/* Opts every same-origin navigation into a smooth crossfade instead of
   an instant swap. No-op (falls back to today's behavior) in browsers
   that don't support the View Transitions API yet. */
@view-transition {
  navigation: auto;
}

::view-transition-old(root),
::view-transition-new(root) {
  animation-duration: .4s;
  animation-timing-function: cubic-bezier(.16, 1, .3, 1);
}

/* ── FONTS ── */
@import url('https://fonts.googleapis.com/css2?family=Roboto+Mono:ital,wght@0,400;0,700;1,400&family=Plus+Jakarta+Sans:ital,wght@0,300;0,400;0,500;1,300&display=swap');

@font-face {
  font-family: 'Vercetti';
  src: url('Vercetti-Regular.ttf') format('truetype');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Lausanne';
  src: url('TWK Lausanne/TWKLausanne-200.otf') format('opentype');
  font-weight: 200;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Lausanne';
  src: url('TWK Lausanne/TWKLausanne-250.otf') format('opentype');
  font-weight: 250;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Lausanne';
  src: url('TWK Lausanne/TWKLausanne-300 copy.ttf') format('truetype');
  font-weight: 300;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Lausanne';
  src: url('TWK Lausanne/TWKLausanne-400.otf') format('opentype');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Lausanne';
  src: url('TWK Lausanne/TWKLausanne-450.otf') format('opentype');
  font-weight: 450;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Lausanne';
  src: url('TWK Lausanne/TWKLausanne-500.otf') format('opentype');
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Lausanne';
  src: url('TWK Lausanne/TWKLausanne-550 copy.otf') format('opentype');
  font-weight: 550;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Lausanne';
  src: url('TWK Lausanne/TWKLausanne-600 copy.otf') format('opentype');
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Ghost';
  src: url('TWK Ghost/TWKGhost-Light copy.otf') format('opentype');
  font-weight: 300;
  font-style: normal;
  font-display: swap;
}

/* ── TOKENS ── */
:root {
  /* Colours */
  --color-surface:   #080808;
  --color-on-dark:   #f0ede5;
  --color-highlight: #efffa4;
  --color-muted:     #555;
  --color-muted-lg:  #888;
  --divider:         #1a1a1a;

  /* Aliases (backwards compat with index.html) */
  --accent:      var(--color-highlight);
  --bg:          var(--color-surface);
  --white:       var(--color-on-dark);
  --gray:        var(--color-muted);
  --gray-light:  var(--color-muted-lg);

  /* Fonts */
  --font-display: 'Lausanne', Helvetica, sans-serif;
  --font-mono:    'Roboto Mono', monospace;

  /* Type scale — from case study typography.md */
  --type-display-size: 20px;
  --type-heading-size: 24px;
  --type-body-size:    32px;
  --type-label-size:   11px;
  --type-stat-size:    36px;
  --type-tracking:    0;
  --type-line-height:  normal;

  /* Layout */
  --pad: 64px;
}

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

/* ── BASE ── */
html {
  background: var(--color-surface);
  color: var(--color-on-dark);
  font-family: var(--font-mono);
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
  /* Kept on the root element (not body) so it doesn't turn body into a nested
     scroll container — that specifically breaks position: sticky in Safari. */
  overflow-x: hidden;
}

body {
  background: var(--color-surface);
  cursor: none;
}

/* Explicit, not just inherited — browsers apply their own hand cursor to
   interactive elements in ways that don't reliably respect an inherited
   `cursor: none` from body alone. */
a, button, input, select, textarea, label, [role="button"] {
  cursor: none;
}

/* ── CURSOR ── */
#cursor {
  position: fixed;
  width: 8px;
  height: 8px;
  background: var(--color-highlight);
  border-radius: 50%;
  pointer-events: none;
  z-index: 9999;
  transform: translate(-50%, -50%);
  transition: width .25s cubic-bezier(.16,1,.3,1),
              height .25s cubic-bezier(.16,1,.3,1),
              opacity .25s;
  mix-blend-mode: difference;
}
#cursor.expanded {
  width: 32px;
  height: 32px;
  opacity: .4;
}

/* ── NAV ── */
nav {
  view-transition-name: site-nav;
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 28px var(--pad);
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background .4s cubic-bezier(.16,1,.3,1),
              backdrop-filter .4s cubic-bezier(.16,1,.3,1),
              padding .4s cubic-bezier(.16,1,.3,1);
}

nav.scrolled {
  background: rgba(8, 8, 8, .55);
  backdrop-filter: blur(24px) saturate(180%);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  padding: 18px var(--pad);
}

nav::after {
  content: '';
  position: absolute;
  top: 100%; left: 0; right: 0;
  height: 140px;
  background: linear-gradient(to bottom, rgba(8,8,8,.22) 0%, rgba(8,8,8,.08) 45%, transparent 100%);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  /* Tapers the blur itself (not just color) so the bar hands off to the
     page gradually instead of cutting from 40px-blur to 0 in one line */
  -webkit-mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 0%, rgba(0,0,0,.5) 40%, rgba(0,0,0,0) 100%);
  mask-image: linear-gradient(to bottom, rgba(0,0,0,1) 0%, rgba(0,0,0,.5) 40%, rgba(0,0,0,0) 100%);
  pointer-events: none;
  opacity: 0;
  transition: opacity .4s cubic-bezier(.16,1,.3,1);
}

nav.scrolled::after { opacity: 1; }

nav.scrolled .nav-logo,
nav.scrolled .nav-links a {
  color: #ffffff;
}

.nav-logo {
  font-family: 'Lausanne', Helvetica, sans-serif;
  font-size: 14px;
  font-weight: 300;
  text-transform: uppercase;
  color: #000000;
  text-decoration: none;
  opacity: 1;
  transition: color .4s cubic-bezier(.16,1,.3,1);
}

.nav-logo sup {
  font-size: 7px;
  vertical-align: super;
  letter-spacing: 0;
}

.nav-links {
  display: flex;
  gap: 36px;
  list-style: none;
}

.nav-links a {
  font-family: 'Lausanne', Helvetica, sans-serif;
  font-size: 14px;
  font-weight: 300;
  letter-spacing: 0;
  color: #000000;
  text-decoration: none;
  opacity: .6;
  transition: opacity .2s, color .4s cubic-bezier(.16,1,.3,1);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px; left: 0;
  width: 0; height: 1px;
  background: var(--color-highlight);
  transition: width .3s;
}

.nav-links a:hover { opacity: 1; }
.nav-links a:hover::after { width: 100%; }

.nav-links a.active { opacity: 1; }
.nav-links a.active::after { width: 100%; }

/* ── MOBILE NAV TOGGLE (hamburger) ── */
.nav-toggle {
  position: relative;
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 26px;
  height: 20px;
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  z-index: 101;
  grid-column: 3;
  justify-self: end;
}

.nav-toggle span {
  position: relative;
  z-index: 1;
  display: block;
  width: 100%;
  height: 1.5px;
  background: #000000;
  transition: transform .35s cubic-bezier(.16,1,.3,1), opacity .2s, background .3s;
}

.nav-toggle:hover span { background: var(--color-muted-lg); }

.nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, .35);
  opacity: 0;
  pointer-events: none;
  transition: opacity .4s cubic-bezier(.16,1,.3,1);
  z-index: 98;
}

body:has(nav.menu-open) { overflow: hidden; }

@media (max-width: 600px) {
  .nav-toggle { display: flex; }

  nav.menu-open .nav-toggle span:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
  nav.menu-open .nav-toggle span:nth-child(2) { opacity: 0; }
  nav.menu-open .nav-toggle span:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }
  nav.menu-open .nav-toggle span { background: var(--color-muted-lg) !important; }

  nav.menu-open ~ .nav-overlay { opacity: 1; pointer-events: auto; }

  .nav-links {
    position: fixed !important;
    top: 0 !important;
    right: 0 !important;
    left: auto !important;
    height: 100vh !important;
    width: 100% !important;
    max-width: none !important;
    margin: 0 !important;
    background: #000000 !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    border: none !important;
    box-shadow: none !important;
    border-radius: 0 !important;
    flex-direction: column !important;
    justify-content: center !important;
    align-items: stretch !important;
    gap: 0 !important;
    padding: 0 !important;
    transform: translateX(100%);
    transition: transform .5s cubic-bezier(.16,1,.3,1);
    z-index: 100;
  }

  nav.menu-open .nav-links { transform: translateX(0); }

  .nav-links li { width: 100%; }

  /* Same wipe-fill treatment as .next-project on the case-study pages,
     inverted (white fill / black text) since this panel is black */
  .nav-links a {
    position: relative;
    z-index: 0;
    display: block;
    width: 100%;
    text-align: center;
    font-size: 24px !important;
    font-weight: 300 !important;
    color: #ffffff !important;
    opacity: 1 !important;
    padding: 18px 44px !important;
    background: none !important;
    border-radius: 0 !important;
    transition: color .3s;
  }

  /* Outranks page-specific `nav.scrolled .nav-links a:not(.active)` color
     overrides (used to darken links over a light scrolled nav) so an
     unselected link never goes dark-on-dark inside this black panel. */
  body nav.menu-open .nav-links a:not(.active):not(:hover) {
    color: #ffffff !important;
  }

  .nav-links a::before {
    content: '';
    position: absolute;
    inset: 0;
    background: #ffffff;
    transform: scaleX(0);
    transform-origin: left;
    transition: transform .4s cubic-bezier(.16,1,.3,1);
    z-index: -1;
  }

  .nav-links a:hover { color: #000000 !important; }
  .nav-links a:hover::before { transform: scaleX(1); }

  .nav-links a::after { display: none !important; }
}

/* ── DIVIDER ── */
.divider {
  width: 100%;
  height: 1px;
  background: var(--divider);
}

/* ── FOOTER ── */
footer {
  background: #000000;
  padding: 30px var(--pad);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-text {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: #FFFFFF;
  opacity: .7;
}

/* Two-line credit on the left of the footer */
.footer-credit { line-height: 1.8; }

/* ── ANIMATIONS ── */
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .8s cubic-bezier(.16,1,.3,1),
              transform .8s cubic-bezier(.16,1,.3,1);
}
.reveal.visible { opacity: 1; transform: none; }

/* ── NAV SCROLL JS (shared) ── */
/* Applied via JS: nav.classList.toggle('scrolled', scrollY > 20) */

/* ── RESPONSIVE — shared breakpoints ── */
@media (max-width: 900px) {
  :root { --pad: 40px; }
  nav.scrolled { padding: 16px var(--pad); }
}

@media (max-width: 600px) {
  :root { --pad: 24px; }
  body { cursor: auto; }
  #cursor { display: none; }
  nav { padding: 20px var(--pad); }
  nav.scrolled { padding: 14px var(--pad); }
  .nav-links { gap: 20px; }
  footer { flex-direction: column; gap: 8px; align-items: flex-start; }
  .footer-links { flex-direction: column !important; align-items: flex-start !important; gap: 8px !important; }
}

@media (max-width: 480px) {
  :root { --pad: 16px; }
  .nav-logo { font-size: 11px; }
  .nav-links { gap: 8px; }
  .nav-links a { font-size: 11px; }
}

/* ── NAV — Hong Kong time (moved up from the footer) ──
   Sits in the empty right column of the nav grid. A desktop/tablet-only
   touch: hidden below 700px, where that column gets too narrow for it
   (and, under 600px, the spot belongs to the menu button). */
.nav-time {
  grid-column: 3;
  grid-row: 1;
  justify-self: end;
  align-self: center;
  font-family: 'Lausanne', Helvetica, sans-serif;
  font-size: 18px; /* same as Work / About */
  font-weight: 300;
  color: #000000;
  opacity: .6;
  white-space: nowrap;
}

@media (max-width: 699px) {
  .nav-time { display: none; }
}