:root {
  --bg-black: #000000;
  --bg-card: rgba(0, 0, 0, 0.91);
  --bg-footer: #181828;
  --text-main: #ffffff;
  --text-muted: #99a9b5;
  --accent: #00bcd4;
  --bolt: #2c2e3d;
  --header-pad-x: 48px;
  --content-width: 1170px;
  --shadow-card: 0 0 10px rgba(0, 0, 0, 0.5);
  --font-heading: "Montserrat", "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
  --font-body: "Source Sans Pro", "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg-black);
  color: var(--text-main);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 25px;
}

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

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

.page-shell {
  min-height: 100vh;
  background: var(--bg-black);
}

.page-preloader {
  position: fixed;
  inset: 0;
  z-index: 120;
  display: grid;
  place-items: center;
  background: var(--bg-black);
  transition: opacity 0.35s ease, visibility 0.35s ease;
}

.has-loaded .page-preloader {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.page-preloader__spinner {
  width: 42px;
  height: 42px;
  border: 3px solid rgba(255, 255, 255, 0.2);
  border-top-color: #ffffff;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.scroll-top-button {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 90;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: rgba(24, 24, 40, 0.9);
  border: 1px solid rgba(255, 255, 255, 0.18);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease, background-color 0.2s ease;
}

.scroll-top-button::before {
  content: "";
  position: absolute;
  inset: 15px 13px 13px;
  border-top: 2px solid #ffffff;
  border-left: 2px solid #ffffff;
  transform: rotate(45deg);
}

.scroll-top-button.is-visible {
  opacity: 1;
  pointer-events: auto;
}

.scroll-top-button:hover {
  background: rgba(0, 188, 212, 0.82);
  transform: translateY(-2px);
}

.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 100;
  padding: 0;
  transition: background-color 0.28s ease, box-shadow 0.28s ease, backdrop-filter 0.28s ease;
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(33, 35, 49, 0);
  transition: background 0.28s ease;
}

.site-header.is-scrolled::before {
  background: rgba(24, 24, 40, 0.9);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(8px);
}

.site-header__inner {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  width: 100%;
  padding: 22px var(--header-pad-x);
}

.site-brand {
  display: inline-flex;
  align-items: center;
  min-height: 51px;
}

.site-brand__logo {
  height: auto;
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.site-brand__logo--small {
  position: absolute;
  opacity: 0;
  transform: scale(0.96);
}

.site-header.is-scrolled .site-brand__logo--default {
  opacity: 0;
  transform: scale(0.96);
}

.site-header.is-scrolled .site-brand__logo--small {
  opacity: 1;
  transform: scale(1);
}

.hero-section {
  position: relative;
  overflow: hidden;
  min-height: 100vh;
  background-color: var(--bg-black);
  background-image:
    radial-gradient(circle at top, rgba(0, 0, 0, 0.06), rgba(0, 0, 0, 0.45)),
    url("assets/hero-bg.jpg");
  background-position: top center;
  background-repeat: no-repeat;
  background-size: cover;
}

.hero-section::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(to bottom, rgba(0, 0, 0, 0.1) 0%, transparent 22%, transparent 70%, rgba(0, 0, 0, 0.42) 100%);
  pointer-events: none;
}

.hero-section__inner {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 124px 24px 64px;
}

.about-card {
  width: min(100%, 720px);
  padding: 45px 30px 30px;
  background: var(--bg-card);
  text-align: center;
  transition: box-shadow 0.2s ease;
}

.about-card:hover {
  box-shadow: var(--shadow-card);
}

.about-card__icon {
  display: flex;
  justify-content: center;
  margin-bottom: 30px;
}

.about-card__icon svg {
  width: 20px;
  height: 32px;
  fill: var(--bolt);
}

.about-card__title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: 24px;
  font-weight: 700;
  line-height: 38px;
}

.about-card__copy {
  padding-bottom: 84px;
}

.about-card__copy p {
  margin: 0;
}

.about-card__copy a {
  color: #ffffff;
}

.site-footer {
  background: var(--bg-footer);
}

.site-footer__inner {
  width: min(100% - 32px, var(--content-width));
  margin: 0 auto;
  padding: 34px 0 36px;
  display: grid;
  grid-template-columns: 1fr 2fr 1fr;
}

.site-footer__info {
  color: var(--text-muted);
}

.site-footer__info p {
  margin: 0;
}

.site-footer__info p + p {
  margin-top: 2px;
}

.site-footer__info a {
  color: var(--accent);
}

@media (min-width: 1025px) {
  .hero-section {
    background-attachment: fixed;
  }
}

@media (max-width: 1024px) {
  :root {
    --header-pad-x: 28px;
  }
}

@media (max-width: 767px) {
  :root {
    --header-pad-x: 16px;
  }

  .site-header__inner {
    padding: 18px var(--header-pad-x);
  }

  .site-brand__logo--default {
    width: 132px;
  }

  .site-brand__logo--small {
    width: 132px;
  }

  .hero-section {
    min-height: 647px;
    background-position: -81px 180px;
    background-size: 821px auto;
  }

  .hero-section__inner {
    min-height: 647px;
    padding: 108px 20px 48px;
  }

  .about-card {
    width: 100%;
    padding: 45px 24px 24px;
  }

  .about-card__copy {
    padding-bottom: 46px;
  }

  .site-footer__inner {
    grid-template-columns: 1fr;
    padding: 28px 0 32px;
  }
}

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

  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}