/* ========================================
   Apple-inspired Personal Website
   ======================================== */

/* --- Reset & Variables --- */
:root {
  --black: #1d1d1f;
  --white: #fbfbfd;
  --gray-50: #f5f5f7;
  --gray-100: #e8e8ed;
  --gray-200: #d2d2d7;
  --gray-400: #86868b;
  --gray-600: #6e6e73;
  --gray-800: #424245;
  --blue: #0071e3;
  --blue-hover: #0077ed;
  --dark-bg: #000000;
  --dark-surface: #111111;
  --font: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Helvetica Neue', sans-serif;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  color: var(--black);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  line-height: 1.5;
  overflow-x: hidden;
}

a {
  text-decoration: none;
  color: inherit;
}

ul { list-style: none; }
img { max-width: 100%; display: block; }
button { font-family: var(--font); }

/* --- Navigation --- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 9999;
  background: rgba(251, 251, 253, 0.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 0.5px solid rgba(0, 0, 0, 0.08);
}

.nav-container {
  max-width: 1024px;
  margin: 0 auto;
  padding: 0 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 48px;
}

.logo {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.5px;
  color: var(--black);
}

.nav-links {
  display: flex;
  gap: 32px;
}

.nav-links a {
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--gray-800);
  letter-spacing: 0;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--black);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  width: 20px;
  height: 20px;
  position: relative;
}

.nav-toggle span {
  display: block;
  width: 17px;
  height: 1px;
  background: var(--gray-800);
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  transition: all 0.3s;
}

.nav-toggle span:first-child { top: 6px; }
.nav-toggle span:last-child { top: 13px; }

.nav-toggle.active span:first-child {
  top: 9px;
  transform: translateX(-50%) rotate(45deg);
}

.nav-toggle.active span:last-child {
  top: 9px;
  transform: translateX(-50%) rotate(-45deg);
}

/* --- Hero --- */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px 80px;
  position: relative;
  background: linear-gradient(180deg, var(--white) 0%, var(--gray-50) 100%);
}

.hero-headline {
  font-size: clamp(2.8rem, 7vw, 5.5rem);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -0.04em;
  color: var(--black);
  margin-bottom: 24px;
}

.hero-highlight {
  background: linear-gradient(90deg, #2997ff 0%, #a855f7 50%, #ec4899 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-sub {
  font-size: clamp(1rem, 2vw, 1.3rem);
  font-weight: 300;
  color: var(--gray-600);
  max-width: 500px;
  margin: 0 auto 40px;
  line-height: 1.6;
}

.hero-cta {
  margin-bottom: 0;
}

.hero-scroll-indicator {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
}

.scroll-dot {
  width: 24px;
  height: 40px;
  border: 2px solid var(--gray-200);
  border-radius: 12px;
  position: relative;
}

.scroll-dot::after {
  content: '';
  width: 4px;
  height: 8px;
  background: var(--gray-400);
  border-radius: 2px;
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  animation: scrollBounce 2s ease-in-out infinite;
}

@keyframes scrollBounce {
  0%, 100% { top: 6px; opacity: 1; }
  50% { top: 20px; opacity: 0.3; }
}

/* --- Buttons --- */
.btn-apple {
  display: inline-block;
  padding: 12px 28px;
  background: var(--blue);
  color: #fff;
  font-size: 1rem;
  font-weight: 400;
  border-radius: 980px;
  border: none;
  cursor: pointer;
  transition: all 0.3s;
  letter-spacing: -0.01em;
}

.btn-apple:hover {
  background: var(--blue-hover);
  transform: scale(1.02);
}

.btn-apple-large {
  padding: 18px 40px;
  font-size: 1.15rem;
}

.link-arrow {
  display: inline-block;
  font-size: 1.05rem;
  color: var(--blue);
  font-weight: 400;
  transition: all 0.3s;
}

.link-arrow:hover {
  text-decoration: underline;
}

/* --- Section Shared --- */
.section-full {
  padding: 120px 24px;
}

.section-dark {
  background: var(--dark-bg);
  color: var(--white);
}

.section-intro {
  text-align: center;
  max-width: 800px;
  margin: 0 auto 80px;
}

.overline {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--gray-400);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 16px;
}

.section-dark .overline {
  color: var(--gray-400);
}

.headline-large {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: -0.03em;
}

.headline-xl {
  font-size: clamp(3rem, 8vw, 6rem);
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: -0.04em;
  margin-bottom: 24px;
}

.text-gradient {
  background: linear-gradient(90deg, #2997ff, #a855f7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* --- About --- */
.about-content {
  max-width: 860px;
  margin: 0 auto;
}

.about-card {
  background: var(--gray-50);
  border-radius: 24px;
  padding: 60px;
  margin-bottom: 48px;
}

.about-desc {
  font-size: 1.35rem;
  font-weight: 300;
  line-height: 1.7;
  color: var(--gray-800);
  text-align: center;
}

.stats-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 48px;
  text-align: center;
}

.stat-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.stat-num {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, var(--blue), #a855f7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-text {
  font-size: 0.8rem;
  color: var(--gray-600);
  font-weight: 400;
  line-height: 1.4;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.stat-divider {
  width: 1px;
  height: 48px;
  background: var(--gray-200);
}

/* --- Work / Projects --- */
.work-showcase {
  max-width: 1080px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 80px;
}

.work-item {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 60px;
  align-items: center;
}

.work-item-reverse {
  grid-template-columns: 1fr 1.2fr;
}

.work-item-reverse .work-visual {
  order: 2;
}

.work-item-reverse .work-details {
  order: 1;
}

.work-placeholder {
  width: 100%;
  aspect-ratio: 16/10;
  border-radius: 20px;
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  transition: transform 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}

.work-item:hover .work-placeholder {
  transform: scale(1.02);
}

.work-placeholder span {
  font-size: 4rem;
  font-weight: 800;
  color: rgba(255,255,255,0.08);
  letter-spacing: -0.03em;
}

.work-placeholder-2 {
  background: linear-gradient(135deg, #0d1117 0%, #161b22 50%, #21262d 100%);
}

.work-placeholder-3 {
  background: linear-gradient(135deg, #1a1a2e 0%, #2d1b69 50%, #11998e 100%);
}

.work-category {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--gray-400);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 8px;
}

.work-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  color: var(--white);
}

.work-desc {
  font-size: 1rem;
  font-weight: 300;
  color: var(--gray-400);
  line-height: 1.7;
  margin-bottom: 20px;
}

.work-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}

.work-tags span {
  padding: 6px 16px;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 980px;
  font-size: 0.8rem;
  color: var(--gray-400);
}

.section-dark .link-arrow {
  color: #2997ff;
}

/* --- Skills --- */
.skills-showcase {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.skill-block {
  background: var(--gray-50);
  border-radius: 20px;
  padding: 40px 48px;
  display: flex;
  align-items: flex-start;
  gap: 48px;
  transition: transform 0.3s, box-shadow 0.3s;
}

.skill-block:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(0,0,0,0.06);
}

.skill-block-header {
  min-width: 160px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.skill-number {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--blue);
  letter-spacing: 0.05em;
}

.skill-block h3 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.skill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding-top: 6px;
}

.skill-list span {
  padding: 8px 20px;
  background: var(--white);
  border: 1px solid var(--gray-100);
  border-radius: 980px;
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--gray-800);
  transition: all 0.3s;
}

.skill-list span:hover {
  background: var(--black);
  color: var(--white);
  border-color: var(--black);
}

/* --- Contact --- */
.contact-wrapper {
  text-align: center;
  max-width: 700px;
  margin: 0 auto;
}

.contact-sub {
  font-size: 1.15rem;
  font-weight: 300;
  color: var(--gray-400);
  line-height: 1.7;
  margin-bottom: 48px;
}

.contact-actions {
  margin-bottom: 48px;
}

.contact-socials {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
}

.contact-socials a {
  font-size: 0.9rem;
  color: var(--gray-400);
  transition: color 0.3s;
}

.contact-socials a:hover {
  color: var(--white);
}

.social-dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--gray-600);
}

/* --- Footer --- */
.footer {
  padding: 20px 24px;
  background: var(--dark-bg);
  border-top: 0.5px solid rgba(255,255,255,0.06);
}

.footer-inner {
  max-width: 1024px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer p {
  font-size: 0.75rem;
  color: var(--gray-600);
}

.footer-sub {
  font-size: 0.7rem;
  color: var(--gray-800);
}

/* --- Animations --- */
.fade-up {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.8s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

.delay-1 { transition-delay: 0.15s; }
.delay-2 { transition-delay: 0.3s; }
.delay-3 { transition-delay: 0.45s; }

/* --- Responsive --- */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .nav-links {
    position: fixed;
    top: 48px;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(251, 251, 253, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 40px;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.4s;
  }

  .nav-links.open {
    opacity: 1;
    pointer-events: auto;
  }

  .nav-links a {
    font-size: 1.2rem;
  }

  .hero {
    padding: 100px 20px 60px;
  }

  .hero-headline {
    font-size: 2.4rem;
  }

  .section-full {
    padding: 80px 20px;
  }

  .section-intro {
    margin-bottom: 48px;
  }

  .about-card {
    padding: 36px 24px;
  }

  .about-desc {
    font-size: 1.1rem;
  }

  .stats-row {
    flex-direction: column;
    gap: 32px;
  }

  .stat-divider {
    width: 48px;
    height: 1px;
  }

  .work-item,
  .work-item-reverse {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .work-item-reverse .work-visual { order: 0; }
  .work-item-reverse .work-details { order: 0; }

  .work-title {
    font-size: 1.5rem;
  }

  .skill-block {
    flex-direction: column;
    gap: 20px;
    padding: 28px 24px;
  }

  .skill-block-header {
    min-width: auto;
  }

  .headline-xl {
    font-size: 2.5rem;
  }

  .footer-inner {
    flex-direction: column;
    gap: 4px;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .hero-headline {
    font-size: 2rem;
  }

  .headline-large {
    font-size: 1.6rem;
  }

  .stat-num {
    font-size: 2.2rem;
  }
}