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

:root {
  --bg: #ffffff;
}

html,
body {
  width: 100%;
}

body {
  background: var(--bg);
}

.logo {
  position: fixed;
  top: clamp(10px, 1.5vw, 20px);
  left: clamp(10px, 1.5vw, 20px);
  z-index: 10;
  display: block;
  padding: clamp(6px, 0.8vw, 10px) clamp(8px, 1vw, 14px);
  line-height: 0;
  background: #fff;
  border: 1px solid #ccc;
  border-radius: 10px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12);
  transition:
    border-color 0.2s ease,
    box-shadow 0.2s ease;
}

.logo:hover {
  border-color: #999;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.16);
}

.logo img {
  display: block;
  width: clamp(68px, 12vw, 140px);
  height: auto;
}

.fv {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 100vh;
  min-height: 100dvh;
}

.fv picture {
  display: block;
  width: 100%;
}

.fv__image {
  display: block;
  width: 100%;
  height: auto;
}