/* =================================================================
   Kaden Yeung — Portfolio
   Design tokens → base → layout → components → responsive
   ================================================================= */

/* ----- Design Tokens ----- */
:root {
  /* Color */
  --bg: #ffffff;
  --bg-subtle: #f7f8fa;
  --surface: #ffffff;
  --text: #0f1115;
  --text-secondary: #515a67;
  --text-muted: #8a94a3;
  --border: #e9ebef;
  --border-strong: #d9dde3;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-soft: rgba(37, 99, 235, 0.08);
  --ring: rgba(37, 99, 235, 0.35);

  /* Type */
  --font-serif: "Fraunces", Georgia, "Times New Roman", serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Helvetica, Arial, sans-serif;

  /* Layout */
  --max-width: 1120px;
  --gutter: clamp(1.25rem, 4vw, 2.5rem);
  --section-py: clamp(3.5rem, 8vw, 7.5rem);
  --nav-h: 70px;

  /* Radius */
  --radius: 18px;
  --radius-sm: 12px;
  --radius-pill: 999px;

  /* Shadow */
  --shadow-sm: 0 1px 2px rgba(15, 17, 21, 0.04), 0 2px 4px rgba(15, 17, 21, 0.04);
  --shadow-md: 0 6px 20px -6px rgba(15, 17, 21, 0.1),
    0 2px 8px -4px rgba(15, 17, 21, 0.06);
  --shadow-lg: 0 28px 60px -18px rgba(15, 17, 21, 0.22);

  /* Motion */
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --t-fast: 0.18s;
  --t: 0.3s;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 16px);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
  -webkit-tap-highlight-color: transparent;
}

/* Lock background scroll while the mobile menu is open */
body.menu-open {
  overflow: hidden;
}

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

a {
  color: var(--accent);
  text-decoration: none;
}

ul {
  list-style: none;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ----- Typography ----- */
h1,
h2 {
  font-family: var(--font-serif);
  font-weight: 500;
  font-optical-sizing: auto;
  line-height: 1.08;
  letter-spacing: -0.015em;
}

h3 {
  font-family: var(--font-sans);
  font-weight: 600;
  letter-spacing: -0.01em;
}

strong {
  font-weight: 600;
  color: var(--text);
}

/* ----- Layout helpers ----- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

/* Keep padded content clear of notches / rounded corners (esp. landscape) */
@supports (padding: max(0px)) {
  .container,
  .nav-container {
    padding-left: max(var(--gutter), env(safe-area-inset-left));
    padding-right: max(var(--gutter), env(safe-area-inset-right));
  }

  .site-footer {
    padding-bottom: max(2.75rem, env(safe-area-inset-bottom));
  }
}

.section {
  padding-block: var(--section-py);
}

.section-alt {
  background: var(--bg-subtle);
  border-block: 1px solid var(--border);
}

.section-header {
  max-width: 640px;
  margin-bottom: clamp(2.5rem, 5vw, 3.75rem);
}

.section-heading {
  font-size: clamp(2rem, 4.2vw, 2.85rem);
}

.section-intro {
  margin-top: 0.85rem;
  font-size: 1.075rem;
  color: var(--text-secondary);
}

.skip-link {
  position: absolute;
  left: 50%;
  top: -100px;
  transform: translateX(-50%);
  z-index: 2000;
  background: var(--text);
  color: #fff;
  padding: 0.7rem 1.2rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  transition: top var(--t-fast) var(--ease);
}

.skip-link:focus {
  top: 12px;
}

/* ----- Buttons ----- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.55rem;
  padding: 0.85rem 1.5rem;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 0.975rem;
  border: 1.5px solid transparent;
  cursor: pointer;
  transition: transform var(--t-fast) var(--ease),
    box-shadow var(--t-fast) var(--ease), background var(--t-fast) var(--ease),
    color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.btn i {
  font-size: 1.15rem;
}

.btn-primary {
  background: var(--text);
  color: #fff;
}

.btn-primary:hover {
  background: #000;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--border-strong);
}

.btn-ghost:hover {
  border-color: var(--text);
  transform: translateY(-2px);
}

.btn-ghost i {
  transition: transform var(--t-fast) var(--ease);
}

.btn-ghost:hover i {
  transform: translateX(3px);
}

/* =================================================================
   Navigation
   ================================================================= */
.main-nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--t) var(--ease),
    box-shadow var(--t) var(--ease), background var(--t) var(--ease);
}

.main-nav.is-scrolled {
  border-bottom-color: var(--border);
  box-shadow: var(--shadow-sm);
}

.nav-container {
  max-width: var(--max-width);
  min-height: var(--nav-h);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.nav-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--text);
  font-weight: 600;
}

.nav-logo {
  height: 34px;
  width: auto;
}

.nav-name {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-link {
  position: relative;
  padding: 0.5rem 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: color var(--t-fast) var(--ease),
    background var(--t-fast) var(--ease);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0.85rem;
  right: 0.85rem;
  bottom: 0.3rem;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--t-fast) var(--ease);
}

.nav-link:hover {
  color: var(--text);
}

.nav-link:hover::after,
.nav-link.is-active::after {
  transform: scaleX(1);
}

.nav-link.is-active {
  color: var(--text);
}

.nav-cta {
  margin-left: 0.5rem;
  padding: 0.55rem 1.15rem;
  background: var(--text);
  color: #fff;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform var(--t-fast) var(--ease),
    background var(--t-fast) var(--ease);
}

.nav-cta:hover {
  background: #000;
  transform: translateY(-1px);
}

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 10px;
  background: transparent;
  border: none;
  cursor: pointer;
  border-radius: var(--radius-sm);
}

.nav-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--text);
  border-radius: 2px;
  transition: transform var(--t-fast) var(--ease),
    opacity var(--t-fast) var(--ease);
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* =================================================================
   Hero
   ================================================================= */
.hero {
  position: relative;
  padding-block: clamp(3.5rem, 7vw, 6rem) clamp(3rem, 6vw, 5rem);
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: -20%;
  right: -10%;
  width: 50vw;
  height: 50vw;
  max-width: 640px;
  max-height: 640px;
  background: radial-gradient(
    circle,
    rgba(37, 99, 235, 0.1),
    transparent 65%
  );
  filter: blur(20px);
  z-index: -1;
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: clamp(2.5rem, 6vw, 5rem);
  align-items: center;
}

.hero-title {
  font-size: clamp(2.4rem, 8vw, 4.75rem);
  margin-bottom: 1.25rem;
}

.hero-lead {
  font-size: clamp(1.2rem, 2.2vw, 1.45rem);
  line-height: 1.5;
  color: var(--text);
  font-weight: 500;
  max-width: 34ch;
  margin-bottom: 1.75rem;
}

.hero-bio {
  color: var(--text-secondary);
  max-width: 52ch;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.cta-container {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 2rem;
}

/* Social row */
.hero-social {
  display: flex;
  gap: 0.65rem;
  margin-top: 2rem;
}

.hero-social a {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--border);
  border-radius: 50%;
  color: var(--text-secondary);
  font-size: 1.3rem;
  background: var(--surface);
  transition: color var(--t-fast) var(--ease),
    border-color var(--t-fast) var(--ease),
    transform var(--t-fast) var(--ease), background var(--t-fast) var(--ease);
}

.hero-social a:hover {
  color: #fff;
  background: var(--text);
  border-color: var(--text);
  transform: translateY(-3px);
}

/* Hero image */
.hero-figure {
  justify-self: center;
  width: 100%;
  max-width: 420px;
}

.hero-figure-inner {
  position: relative;
  isolation: isolate;
}

.hero-figure-inner::before {
  content: "";
  position: absolute;
  inset: 18px -18px -18px 18px;
  border: 1.5px solid var(--border-strong);
  border-radius: var(--radius);
  z-index: -1;
}

.profile-img {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
}

/* =================================================================
   "Now" strip
   ================================================================= */
.now-strip {
  background: var(--bg-subtle);
  border-block: 1px solid var(--border);
  padding-block: 2rem;
}

.now-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
}

.now-tag {
  padding: 0.6rem 1.15rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text);
  transition: transform var(--t-fast) var(--ease),
    box-shadow var(--t-fast) var(--ease);
}

.now-tag:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

/* =================================================================
   Projects
   ================================================================= */
.project-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.project-card {
  display: flex;
  flex-direction: column;
  padding: clamp(1.5rem, 3vw, 2.25rem);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: transform var(--t) var(--ease),
    box-shadow var(--t) var(--ease), border-color var(--t) var(--ease);
}

.project-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
}

.project-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.project-index {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--accent);
}

.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: flex-end;
}

.tag-row li {
  padding: 0.3rem 0.7rem;
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.project-title {
  font-size: 1.3rem;
  margin-bottom: 0.85rem;
}

.project-description {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.project-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  margin-top: auto;
  font-weight: 600;
  color: var(--accent);
}

.project-link i {
  transition: transform var(--t-fast) var(--ease);
}

.project-card:hover .project-link i {
  transform: translateX(3px);
}

/* =================================================================
   Experience
   ================================================================= */
.experience-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.experience-card {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
  padding: clamp(1.5rem, 3vw, 2rem);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: inherit;
  position: relative;
  overflow: hidden;
  transition: transform var(--t) var(--ease),
    box-shadow var(--t) var(--ease), border-color var(--t) var(--ease);
}

.experience-card::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  height: 3px;
  width: 100%;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--t) var(--ease);
}

.experience-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
}

.experience-card:hover::after {
  transform: scaleX(1);
}

.company-logo {
  flex-shrink: 0;
  width: 84px;
  height: 84px;
  display: grid;
  place-items: center;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.85rem;
}

.company-logo img {
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: contain;
}

.experience-details {
  min-width: 0;
}

.experience-details h3 {
  font-size: 1.2rem;
  margin-bottom: 0.45rem;
}

.experience-details p {
  color: var(--text-secondary);
  font-size: 0.975rem;
}

.link-hint {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  margin-top: 0.9rem;
  font-weight: 600;
  color: var(--accent);
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity var(--t) var(--ease), transform var(--t) var(--ease);
}

.experience-card:hover .link-hint {
  opacity: 1;
  transform: translateX(0);
}

/* =================================================================
   Contact
   ================================================================= */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1.5rem;
}

.contact-card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1rem;
  padding: 1.6rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: inherit;
  transition: transform var(--t-fast) var(--ease),
    box-shadow var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.contact-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
}

.contact-card i {
  flex-shrink: 0;
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  font-size: 1.3rem;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: var(--radius-sm);
}

.contact-info {
  min-width: 0;
}

.contact-info h3 {
  font-size: 1.08rem;
  margin-bottom: 0.15rem;
}

.contact-info p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  overflow-wrap: break-word;
}

/* =================================================================
   Footer
   ================================================================= */
.site-footer {
  background: var(--bg-subtle);
  border-top: 1px solid var(--border);
  padding-block: 2.75rem;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  color: var(--text);
}

.footer-logo {
  height: 42px;
  width: auto;
}

.footer-name {
  display: block;
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
}

.footer-tag {
  display: block;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.footer-social {
  display: flex;
  gap: 0.6rem;
}

.footer-social a {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--surface);
  color: var(--text-secondary);
  font-size: 1.2rem;
  transition: color var(--t-fast) var(--ease),
    background var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease),
    transform var(--t-fast) var(--ease);
}

.footer-social a:hover {
  color: #fff;
  background: var(--text);
  border-color: var(--text);
  transform: translateY(-3px);
}

.footer-copy {
  width: 100%;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  text-align: center;
  font-size: 0.875rem;
  color: var(--text-muted);
}

/* =================================================================
   Scroll-reveal animation
   ================================================================= */
[data-reveal] {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* Stagger cards within a grid */
.project-grid [data-reveal]:nth-child(2),
.experience-grid [data-reveal]:nth-child(2),
.contact-grid [data-reveal]:nth-child(2) {
  transition-delay: 0.08s;
}
.project-grid [data-reveal]:nth-child(3),
.experience-grid [data-reveal]:nth-child(3),
.contact-grid [data-reveal]:nth-child(3) {
  transition-delay: 0.16s;
}
.project-grid [data-reveal]:nth-child(4),
.experience-grid [data-reveal]:nth-child(4),
.contact-grid [data-reveal]:nth-child(4) {
  transition-delay: 0.24s;
}
.experience-grid [data-reveal]:nth-child(5) {
  transition-delay: 0.32s;
}
.experience-grid [data-reveal]:nth-child(6) {
  transition-delay: 0.4s;
}

/* =================================================================
   Responsive
   ================================================================= */
@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 2.75rem;
  }

  .hero-figure {
    order: -1;
    max-width: 300px;
  }

  .hero-figure-inner::before {
    inset: 14px -14px -14px 14px;
  }

  .hero-lead {
    max-width: none;
  }

  .project-grid,
  .experience-grid {
    grid-template-columns: 1fr;
  }

  /* Cards are full-width single-column here, so always show the
     "View details →" CTA instead of waiting for a hover that may
     never come on a narrow / touch layout. */
  .link-hint {
    opacity: 1;
    transform: none;
  }
}

@media (max-width: 820px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0.25rem;
    padding: 0.85rem var(--gutter) 1.25rem;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    /* Stay scrollable if the menu ever exceeds the viewport (landscape) */
    max-height: calc(100vh - var(--nav-h));
    overflow-y: auto;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--t) var(--ease), opacity var(--t) var(--ease),
      visibility var(--t) var(--ease);
  }

  .nav-links.is-open {
    transform: none;
    opacity: 1;
    visibility: visible;
  }

  .nav-link {
    padding: 0.85rem 0.75rem;
    font-size: 1.05rem;
    border-bottom: 1px solid var(--border);
    border-radius: 0;
  }

  .nav-link::after {
    display: none;
  }

  .nav-cta {
    margin: 0.85rem 0 0;
    padding: 0.85rem;
    text-align: center;
  }
}

@media (max-width: 560px) {
  .nav-name {
    display: none;
  }

  .project-top {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.85rem;
  }

  .tag-row {
    justify-content: flex-start;
  }

  .experience-card {
    flex-direction: column;
    gap: 1.1rem;
  }

  .cta-container .btn {
    width: 100%;
  }

  .footer-inner {
    flex-direction: column;
    text-align: center;
  }

  .footer-brand {
    flex-direction: column;
    text-align: center;
  }
}

/* =================================================================
   Touch / coarse-pointer refinements
   On phones & most tablets :hover is unreliable — it fires on tap and
   "sticks." Reveal hover-gated CTAs, drop the stuck "lift," and add a
   real press state instead.
   ================================================================= */
@media (hover: none) {
  /* The "Visit website →" hints are opacity:0 until hover on desktop —
     show them so touch users can see each card is a link. */
  .link-hint {
    opacity: 1;
    transform: none;
  }

  /* Don't leave a translateY / shadow "lifted" state stuck after a tap. */
  .btn:hover,
  .nav-cta:hover,
  .hero-social a:hover,
  .now-tag:hover,
  .project-card:hover,
  .experience-card:hover,
  .contact-card:hover,
  .footer-social a:hover {
    transform: none;
    box-shadow: none;
  }
}

/* Tactile press feedback. Declared last so it wins over the neutralized
   :hover rules above while a tap is active. */
.btn:active {
  transform: scale(0.97);
}

.project-card:active,
.experience-card:active,
.contact-card:active,
.now-tag:active,
.hero-social a:active,
.footer-social a:active {
  transform: scale(0.985);
}

/* =================================================================
   Reduced motion
   ================================================================= */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  [data-reveal] {
    opacity: 1;
    transform: none;
  }
}