/* ================================================
   TWINCO — Design System & Global Styles
   ================================================ */

:root {
  /* Core Palette */
  --bg-0:          #050c18;
  --bg-1:          #070d1a;
  --bg-2:          #0b1526;
  --bg-card:       #0e1b30;
  --bg-elevated:   #112240;

  --accent-blue:   #00c2ff;
  --accent-green:  #06c755;
  --accent-purple: #8b5cf6;

  --text-0:        #f0f4ff;
  --text-1:        #8a9bbf;
  --text-2:        #3d5068;

  --border:        rgba(255,255,255,0.07);
  --border-bright: rgba(255,255,255,0.13);

  /* Typography */
  --font: 'Noto Sans TC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* Spacing */
  --section-v:   clamp(80px, 12vw, 160px);
  --content-max: 1080px;
  --gap-feature: clamp(48px, 7vw, 96px);

  /* Easing */
  --ease-out:    cubic-bezier(0.16, 1, 0.3, 1);
  --ease-inout:  cubic-bezier(0.4, 0, 0.2, 1);
}

/* ── Reset ─────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font);
  background: var(--bg-1);
  color: var(--text-0);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent-blue); text-decoration: none; }
button { font-family: var(--font); }

/* ── Scroll-animation: initial hidden state ── */
.feature .feature-media,
.feature .feature-content,
.feature-center-inner > * {
  opacity: 0;
  transform: translateY(56px);
  transition:
    opacity  0.9s var(--ease-out),
    transform 0.9s var(--ease-out);
}
.feature.visible .feature-media    { opacity: 1; transform: none; transition-delay: 0s; }
.feature.visible .feature-content  { opacity: 1; transform: none; transition-delay: 0.18s; }
.feature-center-inner > *:nth-child(1) { transition-delay: 0s; }
.feature-center-inner > *:nth-child(2) { transition-delay: 0.1s; }
.feature-center-inner > *:nth-child(3) { transition-delay: 0.22s; }
.feature-center-inner > *:nth-child(4) { transition-delay: 0.34s; }
.feature.visible .feature-center-inner > * { opacity: 1; transform: none; }

.cta-eyebrow, .cta-heading, .cta-desc, .cta-actions,
.faq-heading {
  opacity: 0;
  transform: translateY(36px);
  transition: opacity 0.8s var(--ease-out), transform 0.8s var(--ease-out);
}
.cta-eyebrow { transition-delay: 0s; }
.cta-heading { transition-delay: 0.1s; }
.cta-desc    { transition-delay: 0.2s; }
.cta-actions { transition-delay: 0.3s; }

.section-visible .cta-eyebrow,
.section-visible .cta-heading,
.section-visible .cta-desc,
.section-visible .cta-actions,
.section-visible .faq-heading {
  opacity: 1;
  transform: none;
}

/* ================================================
   NAV
   ================================================ */
.nav {
  position: fixed;
  inset-block-start: 0;
  inset-inline: 0;
  z-index: 200;
  padding: 18px 24px;
  transition: background 0.4s ease, backdrop-filter 0.4s ease, border-color 0.4s ease;
  border-bottom: 1px solid transparent;
}
.nav.scrolled {
  background: rgba(5, 12, 24, 0.82);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-bottom-color: var(--border);
}
.nav-inner {
  max-width: var(--content-max);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.nav-logo {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-0);
  letter-spacing: -0.03em;
}
.nav-cta {
  padding: 8px 22px;
  background: var(--accent-green);
  color: #fff;
  border-radius: 999px;
  font-size: 0.875rem;
  font-weight: 600;
  transition: opacity 0.2s, transform 0.2s var(--ease-out);
}
.nav-cta:hover { opacity: 0.88; transform: translateY(-1px); }

/* ================================================
   HERO
   ================================================ */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

/* Background layers */
.hero-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(rgba(0,194,255,0.06) 1px, transparent 1px);
  background-size: 40px 40px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 50%, black 30%, transparent 80%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 50%, black 30%, transparent 80%);
}
.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(90px);
  animation: glow-breathe 7s ease-in-out infinite alternate;
}
.hero-glow--blue {
  width: 700px; height: 700px;
  background: radial-gradient(circle, rgba(0,194,255,0.28) 0%, transparent 65%);
  top: -200px; left: -150px;
  animation-delay: 0s;
}
.hero-glow--purple {
  width: 560px; height: 560px;
  background: radial-gradient(circle, rgba(139,92,246,0.28) 0%, transparent 65%);
  bottom: -120px; right: -80px;
  animation-delay: -3.5s;
}
@keyframes glow-breathe {
  from { opacity: 0.7; transform: scale(1); }
  to   { opacity: 1;   transform: scale(1.18); }
}

/* Content */
.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 0 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
}
.hero-badge {
  display: inline-block;
  padding: 6px 18px;
  border: 1px solid rgba(0,194,255,0.45);
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-blue);
  background: rgba(0,194,255,0.08);
  margin-bottom: 28px;
}
.hero-title {
  font-size: clamp(5rem, 16vw, 11rem);
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.05em;
  background: linear-gradient(145deg, #ffffff 0%, #b8d4ff 45%, #00c2ff 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 28px;
}
.hero-subtitle {
  font-size: clamp(1.1rem, 2.5vw, 1.5rem);
  color: var(--text-1);
  font-weight: 300;
  line-height: 1.75;
  margin-bottom: 52px;
}
.hero-scroll-hint {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  color: var(--text-2);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  text-decoration: none;
  transition: color 0.25s;
  animation: hint-bounce 2.2s ease-in-out infinite;
}
.hero-scroll-hint:hover { color: var(--text-1); }
.hero-scroll-hint svg { width: 18px; height: 18px; }
@keyframes hint-bounce {
  0%, 100% { transform: translateY(0); }
  55%       { transform: translateY(9px); }
}

/* Hero entrance animation */
.anim-hero {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 1s var(--ease-out), transform 1s var(--ease-out);
}
.anim-hero.visible { opacity: 1; transform: none; }
.anim-hero:nth-child(1) { transition-delay: 0.15s; }
.anim-hero:nth-child(2) { transition-delay: 0.3s; }
.anim-hero:nth-child(3) { transition-delay: 0.48s; }
.anim-hero:nth-child(4) { transition-delay: 0.66s; }

/* ================================================
   FEATURES — shared
   ================================================ */
.feature {
  padding-block: var(--section-v);
  border-top: 1px solid var(--border);
}
.feature-inner {
  max-width: var(--content-max);
  margin: 0 auto;
  padding-inline: 24px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--gap-feature);
  align-items: center;
}

/* Feature: image on RIGHT → content col-1, media col-2 */
.feature--img-right .feature-content { order: 1; }
.feature--img-right .feature-media   { order: 2; }

/* Feature: image on LEFT → media col-1, content col-2 */
.feature--img-left .feature-media   { order: 1; }
.feature--img-left .feature-content { order: 2; }

/* Mockup card (placeholder) */
.feature-media { width: 100%; }
.feature-mockup {
  aspect-ratio: 4 / 3;
  border-radius: 20px;
  overflow: hidden;
  background:
    linear-gradient(135deg,
      hsl(var(--mock-hue, 210) 80% 12%) 0%,
      hsl(var(--mock-hue, 210) 60% 7%)  100%);
  border: 1px solid rgba(255,255,255,0.1);
  box-shadow:
    0 24px 64px rgba(0,0,0,0.5),
    inset 0 1px 0 rgba(255,255,255,0.08);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 14px;
  position: relative;
}
.mockup-deco {
  position: absolute;
  border-radius: 50%;
  filter: blur(50px);
  pointer-events: none;
  opacity: 0.35;
}
.mockup-deco--1 {
  width: 200px; height: 200px;
  background: radial-gradient(circle,
    hsl(var(--mock-hue, 210) 100% 60%) 0%, transparent 70%);
  top: -60px; left: -40px;
}
.mockup-deco--2 {
  width: 160px; height: 160px;
  background: radial-gradient(circle,
    hsl(calc(var(--mock-hue, 210) + 40) 100% 55%) 0%, transparent 70%);
  bottom: -40px; right: -20px;
}
.mockup-icon {
  font-size: 3.2rem;
  line-height: 1;
  position: relative;
  z-index: 1;
}
.mockup-label {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-1);
  position: relative;
  z-index: 1;
}
.mockup-hint {
  font-size: 0.72rem;
  color: var(--text-2);
  border: 1px dashed var(--text-2);
  padding: 3px 12px;
  border-radius: 6px;
  position: relative;
  z-index: 1;
}

/* Feature text */
.feature-tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent-blue);
  margin-bottom: 16px;
}
.feature-title {
  font-size: clamp(1.9rem, 3.5vw, 3rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  color: var(--text-0);
  margin-bottom: 20px;
}
.feature-title--xl {
  font-size: clamp(2.6rem, 6vw, 4.5rem);
  margin-bottom: 24px;
}
.feature-desc {
  font-size: 1.05rem;
  color: var(--text-1);
  line-height: 1.8;
  font-weight: 300;
  margin-bottom: 28px;
}
.feature-desc--wide {
  max-width: 540px;
  margin-inline: auto;
  font-size: 1.15rem;
  margin-bottom: 40px;
}
.feature-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.feature-list li {
  padding-inline-start: 22px;
  position: relative;
  color: var(--text-1);
  font-size: 0.95rem;
}
.feature-list li::before {
  content: '';
  position: absolute;
  inset-inline-start: 0;
  top: 9px;
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--accent-blue);
  box-shadow: 0 0 8px var(--accent-blue);
}

/* Feature 5: full-width centered */
.feature--center {
  text-align: center;
  background: var(--bg-2);
}
.feature-center-inner {
  max-width: 680px;
  margin: 0 auto;
  padding-inline: 24px;
}

/* Roadmap chips */
.roadmap-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
}
.chip {
  padding: 8px 20px;
  border-radius: 999px;
  font-size: 0.875rem;
  font-weight: 500;
}
.chip--done {
  background: rgba(6,199,85,0.12);
  color: var(--accent-green);
  border: 1px solid rgba(6,199,85,0.28);
}
.chip--coming {
  background: rgba(0,194,255,0.08);
  color: var(--accent-blue);
  border: 1px dashed rgba(0,194,255,0.4);
}

/* ================================================
   CTA
   ================================================ */
.cta {
  position: relative;
  padding-block: var(--section-v);
  text-align: center;
  overflow: hidden;
  background: var(--bg-2);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.cta-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.cta-glow {
  position: absolute;
  width: 900px; height: 460px;
  background: radial-gradient(ellipse, rgba(6,199,85,0.1) 0%, transparent 65%);
  top: 50%; left: 50%;
  transform: translate(-50%,-50%);
}
.cta-inner {
  position: relative;
  z-index: 1;
  max-width: 560px;
  margin: 0 auto;
  padding-inline: 24px;
}
.cta-eyebrow {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent-green);
  margin-bottom: 16px;
}
.cta-heading {
  font-size: clamp(2.2rem, 5vw, 3.6rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: 20px;
}
.cta-desc {
  color: var(--text-1);
  font-size: 1.05rem;
  font-weight: 300;
  line-height: 1.75;
  margin-bottom: 52px;
}
.cta-actions {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 28px;
}
.qr-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}
.qr-frame {
  width: 176px; height: 176px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-bright);
  border-radius: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 8px 40px rgba(0,0,0,0.45);
  overflow: hidden;
}
.qr-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 16px;
  width: 100%;
}
.qr-placeholder svg {
  width: 100px; height: 100px;
  color: var(--text-1);
}
.qr-placeholder-text {
  font-size: 0.6rem;
  color: var(--text-2);
  text-align: center;
  line-height: 1.3;
}
.qr-label {
  font-size: 0.83rem;
  color: var(--text-2);
}
.cta-divider {
  display: flex;
  align-items: center;
  gap: 14px;
  color: var(--text-2);
  font-size: 0.82rem;
  width: 200px;
}
.cta-divider::before,
.cta-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}
.line-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 16px 36px;
  background: var(--accent-green);
  color: #fff;
  border-radius: 999px;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  text-decoration: none;
  transition: transform 0.25s var(--ease-out), box-shadow 0.25s;
  box-shadow: 0 4px 28px rgba(6,199,85,0.35);
  white-space: nowrap;
}
.line-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 40px rgba(6,199,85,0.5);
}
.line-btn-icon {
  width: 22px; height: 22px;
  flex-shrink: 0;
}

/* ================================================
   FAQ
   ================================================ */
.faq {
  padding-block: var(--section-v);
}
.faq-inner {
  max-width: 700px;
  margin: 0 auto;
  padding-inline: 24px;
}
.faq-heading {
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  text-align: center;
  margin-bottom: 56px;
}
.faq-list { display: flex; flex-direction: column; }
.faq-item { border-bottom: 1px solid var(--border); }
.faq-item:first-child { border-top: 1px solid var(--border); }
.faq-btn {
  width: 100%;
  background: none;
  border: none;
  cursor: pointer;
  padding-block: 22px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  text-align: left;
  color: var(--text-0);
  font-size: 1rem;
  font-weight: 500;
  transition: color 0.2s;
}
.faq-btn:hover { color: var(--accent-blue); }
.faq-btn[aria-expanded="true"] { color: var(--accent-blue); }
.faq-arrow {
  width: 20px; height: 20px;
  flex-shrink: 0;
  color: var(--text-2);
  transition: transform 0.35s var(--ease-out), color 0.2s;
}
.faq-btn[aria-expanded="true"] .faq-arrow {
  transform: rotate(180deg);
  color: var(--accent-blue);
}
.faq-answer {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.4s var(--ease-out);
}
.faq-answer { display: block; }
.faq-answer p {
  padding-bottom: 22px;
  color: var(--text-1);
  font-size: 0.95rem;
  line-height: 1.8;
  font-weight: 300;
}
.faq-answer a {
  color: var(--accent-blue);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ================================================
   FOOTER
   ================================================ */
.footer {
  background: var(--bg-2);
  border-top: 1px solid var(--border);
  padding-block: 40px;
}
.footer-inner {
  max-width: var(--content-max);
  margin: 0 auto;
  padding-inline: 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  text-align: center;
}
.footer-brand { display: flex; align-items: center; gap: 10px; }
.footer-logo {
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--text-0);
  letter-spacing: -0.02em;
}
.footer-by {
  font-size: 0.83rem;
  color: var(--text-2);
}
.footer-links {
  display: flex;
  align-items: center;
  gap: 12px;
}
.footer-links a {
  font-size: 0.875rem;
  color: var(--text-1);
  text-decoration: none;
  transition: color 0.2s;
}
.footer-links a:hover { color: var(--text-0); }
.footer-sep { color: var(--text-2); font-size: 0.875rem; }
.footer-copy { font-size: 0.78rem; color: var(--text-2); }

/* ================================================
   INNER PAGES (terms / privacy)
   ================================================ */
.inner-hero {
  padding-block: 120px 72px;
  text-align: center;
  background: var(--bg-2);
  border-bottom: 1px solid var(--border);
}
.inner-hero-label {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent-blue);
  margin-bottom: 12px;
}
.inner-hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  margin-bottom: 12px;
}
.inner-hero .inner-updated {
  font-size: 0.85rem;
  color: var(--text-2);
}
.inner-content {
  max-width: 680px;
  margin: 0 auto;
  padding: 72px 24px 120px;
}
.inner-content h2 {
  font-size: 1.35rem;
  font-weight: 700;
  margin-top: 48px;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}
.inner-content h2:first-child { margin-top: 0; }
.inner-content p {
  color: var(--text-1);
  font-size: 0.97rem;
  line-height: 1.85;
  font-weight: 300;
  margin-bottom: 16px;
}
.inner-content ul {
  color: var(--text-1);
  font-size: 0.97rem;
  line-height: 1.85;
  font-weight: 300;
  padding-inline-start: 24px;
  margin-bottom: 16px;
}
.inner-content li { margin-bottom: 6px; }
.inner-content a {
  color: var(--accent-blue);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ================================================
   RESPONSIVE
   ================================================ */
@media (max-width: 768px) {
  .feature-inner {
    grid-template-columns: 1fr;
  }
  .feature--img-right .feature-media,
  .feature--img-left .feature-media { order: 0; }
  .feature--img-right .feature-content,
  .feature--img-left .feature-content { order: 1; }

  .feature-mockup { aspect-ratio: 16 / 9; }

  .cta-actions { gap: 20px; }
  .nav { padding: 14px 16px; }
}

@media (max-width: 480px) {
  .hero-title { font-size: 4.2rem; }
  .feature-title { font-size: 1.75rem; }
  .faq-btn { font-size: 0.9rem; }
  .line-btn { padding: 14px 28px; font-size: 0.95rem; }
}