:root {
  --primary: #0078d4;
  --primary-dark: #005a9e;
  --text-main: #333333;
  --text-sub: #777777;
  --border: #eeeeee;
  --bg-page: #ffffff;
  --bg-soft: #f8f9fa;
  --white: #ffffff;
  --header-bg: #1f2933;
  --footer-bg: #222222;
  --footer-text: #cccccc;

  --header-max: 1180px;
  --page-max: 950px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Yu Gothic",
    Meiryo, sans-serif;
  color: var(--text-main);
  background: var(--bg-page);
}

.site-header {
  background: var(--header-bg);
  color: var(--white);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.site-header-container {
  width: 100%;
  max-width: var(--header-max);
  height: 70px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.site-logo {
  color: var(--white);
  text-decoration: none;
  font-size: 19px;
  font-weight: 500;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.site-nav {
  height: 100%;
  display: flex;
  align-items: center;
  gap: 24px;
}

.site-nav-item {
  position: relative;
  height: 100%;
  display: flex;
  align-items: center;
  color: var(--white);
  text-decoration: none;
  font-size: 14px;
  font-weight: 700;
  opacity: 0.88;
  white-space: nowrap;
}

.site-nav-item:hover {
  opacity: 1;
}

.site-nav-item.active::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 14px;
  height: 4px;
  background: var(--white);
}

.page-main {
  flex: 1;
  width: 100%;
}

.page-container {
  width: 100%;
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 34px 20px 48px;
}

.page-title {
  text-align: center;
  font-size: 28px;
  font-weight: 400;
  color: var(--primary);
  letter-spacing: 1px;
  border-bottom: 2px solid var(--primary);
  padding-bottom: 15px;
  margin-bottom: 30px;
}

.footer {
  background: var(--footer-bg);
  color: var(--footer-text);
  text-align: center;
  padding: 18px 24px;
  font-size: 13px;
}

@media (max-width: 860px) {
  .site-header-container {
    height: auto;
    padding: 18px 18px 0;
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
  }

  .site-nav {
    width: 100%;
    height: auto;
    gap: 18px;
    overflow-x: auto;
    padding-bottom: 12px;
    scrollbar-width: none;
  }

  .site-nav::-webkit-scrollbar {
    display: none;
  }

  .site-nav-item {
    height: 38px;
    font-size: 13px;
  }

  .site-nav-item.active::after {
    bottom: 0;
    height: 4px;
  }

  .page-container {
    padding: 28px 16px 42px;
  }

  .page-title {
    font-size: 25px;
  }
}