/* =====================================================
   鑽石託管 | Diamond Host — styles.css
   Aesthetic: editorial dark · refined minimal · tech
   ===================================================== */

:root {
  --bg:          #000000;
  --bg-2:        #07090f;
  --bg-3:        #0b0f18;
  --line:        rgba(255,255,255,0.07);
  --line-bright: rgba(255,255,255,0.14);
  --text:        #e8eef8;
  --muted:       #6b7d96;
  --muted-2:     #8fa0b8;
  --accent:      #4de8b2;
  --accent-2:    #5ab4ff;
  --accent-warm: #f0b354;
  --font-display: 'DM Serif Display', Georgia, serif;
  --font-body:    'DM Sans', system-ui, sans-serif;
  --font-mono:    'DM Mono', 'Fira Code', monospace;
  --max-w:        1120px;
  --r-sm:         6px;
  --r-md:         12px;
  --r-lg:         18px;
  --transition:   200ms 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-body);
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.65;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; background: none; border: none; }
ul { list-style: none; }

/* ── Background atmosphere ── */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 10% 0%, rgba(77,232,178,0.055) 0%, transparent 60%),
    radial-gradient(ellipse 60% 40% at 85% 10%, rgba(90,180,255,0.05) 0%, transparent 55%);
  pointer-events: none;
  z-index: 0;
}
body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: linear-gradient(180deg, rgba(0,0,0,0.3) 0%, transparent 60%);
  pointer-events: none;
  z-index: 0;
}

/* ── Skip nav ── */
.skip-nav {
  position: absolute;
  top: -100%;
  left: 1rem;
  background: var(--accent);
  color: #000;
  padding: .4rem .8rem;
  border-radius: var(--r-sm);
  font-size: .85rem;
  font-weight: 500;
  z-index: 1000;
}
.skip-nav:focus { top: 1rem; }

/* ── Layout helpers ── */
.section-inner,
.header-inner,
.footer-inner {
  width: min(calc(100% - 2.5rem), var(--max-w));
  margin: 0 auto;
}

/* =========================================
   HEADER
   ========================================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  padding: .9rem 0;
  transition: var(--transition);
}
.site-header.scrolled {
  background: rgba(8,15,26,0.88);
  backdrop-filter: blur(16px) saturate(1.4);
  -webkit-backdrop-filter: blur(16px) saturate(1.4);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: .7rem;
  flex-shrink: 0;
}
.brand-mark {
  width: 2.4rem;
  height: 2.4rem;
  border-radius: 8px;
  background: transparent;
  display: grid;
  place-items: center;
  font-family: var(--font-display);
  font-size: 1.1rem;
  color: #050e1a;
  font-weight: 400;
  overflow: hidden;
}
.brand-mark.small { width: 1.6rem; height: 1.6rem; font-size: .8rem; }

.brand-logo {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.brand-name {
  font-size: .95rem;
  font-weight: 500;
  letter-spacing: .01em;
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}
.brand-name em {
  font-style: normal;
  font-size: .75rem;
  font-weight: 300;
  color: var(--muted);
  letter-spacing: .04em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: .15rem;
  margin-left: auto;
}
.site-nav a {
  font-size: .875rem;
  font-weight: 400;
  color: var(--muted-2);
  padding: .45rem .75rem;
  border-radius: var(--r-sm);
  transition: color var(--transition), background var(--transition);
}
.site-nav a:hover { color: var(--text); background: rgba(255,255,255,0.04); }

.nav-cta {
  background: rgba(77,232,178,0.1) !important;
  color: var(--accent) !important;
  border: 1px solid rgba(77,232,178,0.22) !important;
  margin-left: .5rem;
}
.nav-cta:hover { background: rgba(77,232,178,0.18) !important; }

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: .5rem;
  margin-left: auto;
}
.menu-toggle span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--text);
  border-radius: 2px;
  transition: var(--transition);
}

/* =========================================
   HERO
   ========================================= */
.hero {
  position: relative;
  z-index: 1;
  padding: 5.5rem 0 5rem;
}
.hero-inner {
  width: min(calc(100% - 2.5rem), var(--max-w));
  margin: 0 auto;
  display: grid;
  gap: 2.5rem;
  justify-items: center;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  padding: .25rem .7rem;
  border-radius: 999px;
  border: 1px solid rgba(90,180,255,0.35);
  color: var(--accent-2);
  font-size: .7rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  font-family: var(--font-mono);
  margin-bottom: 1.1rem;
}
.hero-badge::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent-2);
  box-shadow: 0 0 8px rgba(90,180,255,0.7);
}

.hero-eyebrow {
  font-family: var(--font-mono);
  font-size: .78rem;
  color: var(--accent);
  letter-spacing: .1em;
  text-transform: uppercase;
  margin-bottom: 1.35rem;
  display: flex;
  align-items: center;
  gap: .6rem;
  justify-content: center;
}
.hero-eyebrow::before {
  content: '';
  width: 28px;
  height: 1px;
  background: var(--accent);
  opacity: .7;
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(3rem, 6.5vw, 5.5rem);
  font-weight: 400;
  line-height: 1.06;
  letter-spacing: -.02em;
  margin-bottom: 1.5rem;
}
.hero h1 em {
  font-style: italic;
  background: linear-gradient(120deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-lead {
  font-size: 1.05rem;
  color: var(--muted-2);
  max-width: 52ch;
  line-height: 1.75;
  margin-bottom: 2.25rem;
}

.hero-cta {
  display: flex;
  gap: .85rem;
  flex-wrap: wrap;
  justify-content: center;
}

/* stat block */

/* =========================================
   BUTTONS
   ========================================= */
.btn {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  padding: .7rem 1.35rem;
  border-radius: var(--r-md);
  font-size: .88rem;
  font-weight: 500;
  transition: var(--transition);
  white-space: nowrap;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #050e1a;
}
.btn-primary:hover { opacity: .88; transform: translateY(-1px); }
.btn-ghost {
  border: 1px solid var(--line-bright);
  color: var(--muted-2);
  background: rgba(255,255,255,0.025);
}
.btn-ghost:hover { border-color: rgba(255,255,255,0.28); color: var(--text); background: rgba(255,255,255,0.05); }

/* =========================================
   SECTIONS — shared
   ========================================= */
.section {
  position: relative;
  z-index: 1;
  padding: 5rem 0;
}
.section + .section { border-top: 1px solid var(--line); }

.section-header {
  margin-bottom: 3rem;
}
.section-label {
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--muted);
  display: block;
  margin-bottom: .75rem;
}
.section-header h2 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3.2rem);
  font-weight: 400;
  line-height: 1.1;
  letter-spacing: -.02em;
}

/* =========================================
   SERVICES
   ========================================= */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
}
.service-card {
  background: var(--bg);
  padding: 2rem 1.75rem;
  transition: background var(--transition);
}
.service-card:hover { background: var(--bg-2); }

.service-tag {
  font-family: var(--font-mono);
  font-size: .7rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  padding: .2rem .6rem;
  border-radius: var(--r-sm);
  border: 1px solid var(--line-bright);
  color: var(--muted-2);
  display: inline-block;
  margin-bottom: 1rem;
}
.service-card h3 {
  font-family: var(--font-display);
  font-size: 1.45rem;
  font-weight: 400;
  letter-spacing: -.01em;
  margin-bottom: .75rem;
}
.service-card > p {
  font-size: .9rem;
  color: var(--muted-2);
  line-height: 1.7;
  margin-bottom: 1.25rem;
}
.service-card ul {
  display: grid;
  gap: .45rem;
  border-top: 1px solid var(--line);
  padding-top: 1.1rem;
}
.service-card li {
  font-size: .83rem;
  color: var(--muted);
  padding-left: 1rem;
  position: relative;
  line-height: 1.5;
}
.service-card li::before {
  content: '';
  position: absolute;
  left: 0;
  top: .55em;
  width: .3rem;
  height: .3rem;
  border-radius: 50%;
  background: var(--accent);
  opacity: .5;
}

/* =========================================
   FEATURES
   ========================================= */
.features-section { background: var(--bg-2); }
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
}
.feature-item {
  background: var(--bg-2);
  padding: 2.25rem 2rem;
  transition: background var(--transition);
}
.feature-item:hover { background: var(--bg-3); }
.feature-num {
  font-family: var(--font-mono);
  font-size: .72rem;
  color: var(--muted);
  opacity: .5;
  display: block;
  margin-bottom: .9rem;
  letter-spacing: .08em;
}
.feature-item h3 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 400;
  letter-spacing: -.01em;
  margin-bottom: .6rem;
}
.feature-item p {
  font-size: .875rem;
  color: var(--muted-2);
  line-height: 1.7;
}

/* =========================================
   FAQ
   ========================================= */
.faq-list {
  display: grid;
  gap: 0;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
}
.faq-item {
  border-bottom: 1px solid var(--line);
  background: var(--bg);
  transition: background var(--transition);
}
.faq-item:last-child { border-bottom: none; }
.faq-item[open] { background: var(--bg-2); }

.faq-item summary {
  list-style: none;
  padding: 1.25rem 1.75rem;
  font-size: .95rem;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  user-select: none;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  font-size: 1.1rem;
  font-weight: 300;
  color: var(--muted);
  flex-shrink: 0;
  transition: transform var(--transition);
}
.faq-item[open] summary::after {
  transform: rotate(45deg);
  color: var(--accent);
}
.faq-item p {
  font-size: .9rem;
  color: var(--muted-2);
  line-height: 1.75;
  padding: 0 1.75rem 1.5rem;
}

/* =========================================
   CONTACT
   ========================================= */
.contact-section {
  background: var(--bg-2);
}
.contact-block {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 3rem;
  align-items: end;
}
.contact-copy .section-label { margin-bottom: .75rem; }
.contact-copy h2 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 3.5vw, 3rem);
  font-weight: 400;
  line-height: 1.1;
  letter-spacing: -.02em;
  margin-bottom: 1rem;
}
.contact-copy p {
  font-size: .92rem;
  color: var(--muted-2);
  max-width: 48ch;
  line-height: 1.75;
}
.contact-links {
  display: flex;
  flex-direction: column;
  gap: .7rem;
  min-width: 220px;
  align-items: center;
}

.contact-links .btn {
  width: 100%;
  max-width: 320px;
  justify-content: center;
}

/* =========================================
   FOOTER
   ========================================= */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 2.5rem 0;
}
.footer-inner {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}
.footer-brand {
  display: flex;
  align-items: center;
  gap: .5rem;
  font-size: .9rem;
  font-weight: 500;
}
.footer-desc {
  font-size: .82rem;
  color: var(--muted);
  flex: 1;
}
.footer-copy {
  font-size: .78rem;
  color: var(--muted);
  opacity: .6;
}

/* =========================================
   RESPONSIVE
   ========================================= */
@media (max-width: 960px) {
  .hero-inner { gap: 2rem; }
  .contact-block { grid-template-columns: 1fr; gap: 2rem; }
  .contact-links { flex-direction: row; flex-wrap: wrap; justify-content: center; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 960px) {
  .contact-links .btn {
    width: clamp(200px, 42vw, 280px);
  }
}

@media (max-width: 720px) {
  .hero { padding: 3.5rem 0 3rem; }
  .services-grid { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr; }

  .site-nav {
    display: none;
    position: absolute;
    top: calc(100% + .5rem);
    left: 1.25rem;
    right: 1.25rem;
    flex-direction: column;
    align-items: stretch;
    background: rgba(10,17,30,0.97);
    border: 1px solid var(--line-bright);
    border-radius: var(--r-lg);
    padding: .5rem;
    backdrop-filter: blur(16px);
  }
  .site-nav.is-open { display: flex; }
  .site-nav a { padding: .75rem 1rem; }
  .nav-cta { margin-left: 0; margin-top: .25rem; }

  .menu-toggle { display: flex; }

  .footer-inner { flex-direction: column; align-items: flex-start; gap: .75rem; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 2.6rem; }
  .section { padding: 3.5rem 0; }
  .service-card, .feature-item { padding: 1.5rem 1.25rem; }
}

/* =========================================
   ANIMATIONS — reduced-motion safe
   ========================================= */
@media (prefers-reduced-motion: no-preference) {
  .hero-copy > * {
    opacity: 0;
    transform: translateY(16px);
    animation: fadeUp .6s cubic-bezier(.22,1,.36,1) forwards;
  }
  .hero-eyebrow { animation-delay: .05s; }
  .hero h1       { animation-delay: .15s; }
  .hero-lead     { animation-delay: .25s; }
  .hero-cta      { animation-delay: .35s; }

  @keyframes fadeUp {
    to { opacity: 1; transform: none; }
  }
}