:root {
  --black: #080a0b;
  --panel: #0d1011;
  --line: #272d2f;
  --text: #c8cecf;
  --muted: #61696b;
  --accent: #74898b;
  --error: #a34a4a;
}

* { box-sizing: border-box; }

html, body { min-height: 100%; }

body {
  min-height: 100vh;
  margin: 0;
  display: flex;
  flex-direction: column;
  color: var(--text);
  background:
    radial-gradient(circle at 50% 42%, rgba(59, 71, 73, .12), transparent 32%),
    var(--black);
  font-family: "Noto Sans JP", "Yu Gothic", "Hiragino Kaku Gothic ProN", sans-serif;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.staff-gate {
  min-height: calc(100vh - 70px);
  padding: 70px 24px;
  display: grid;
  place-items: center;
}

.staff-panel {
  width: min(440px, 100%);
  padding: 54px 48px 49px;
  background: rgba(13, 16, 17, .88);
  border: 1px solid var(--line);
  box-shadow: 0 28px 80px rgba(0, 0, 0, .48);
  text-align: center;
}

.staff-symbol {
  width: 44px;
  height: 44px;
  margin: 0 auto 23px;
  display: grid;
  place-items: center;
  position: relative;
  opacity: .48;
}

.staff-symbol i {
  position: absolute;
  width: 15px;
  height: 31px;
  border: 1px solid #829092;
  border-radius: 80% 20% 80% 20%;
  transform-origin: 50% 75%;
}
.staff-symbol i:nth-child(1) { transform: rotate(0deg) translateY(-3px); }
.staff-symbol i:nth-child(2) { transform: rotate(120deg) translateY(-3px); }
.staff-symbol i:nth-child(3) { transform: rotate(240deg) translateY(-3px); }

.staff-system-name {
  margin: 0 0 9px;
  color: var(--muted);
  font-family: Consolas, "Courier New", monospace;
  font-size: .61rem;
  letter-spacing: .2em;
}

.staff-panel h1 {
  margin: 0 0 31px;
  font-size: 1rem;
  font-weight: 400;
  letter-spacing: .08em;
}

.staff-form { display: grid; grid-template-columns: 1fr 86px; }

.staff-form input {
  min-width: 0;
  height: 48px;
  padding: 0 15px;
  color: #e3e7e8;
  background: #080a0b;
  border: 1px solid #343a3c;
  border-right: 0;
  border-radius: 2px 0 0 2px;
  font-family: Consolas, "Courier New", monospace;
  font-size: 1rem;
  letter-spacing: .18em;
}

.staff-form input::placeholder {
  color: #353b3d;
  font-family: "Yu Gothic", sans-serif;
  font-size: .78rem;
  letter-spacing: .25em;
}

.staff-form input:focus {
  outline: none;
  border-color: #617174;
  box-shadow: inset 0 0 0 1px #617174;
}

.staff-form button {
  color: #d1d7d8;
  background: #30383a;
  border: 1px solid #414a4c;
  border-radius: 0 2px 2px 0;
  font: inherit;
  font-size: .76rem;
  cursor: pointer;
  transition: background .18s;
}
.staff-form button:hover { background: #3b4547; }

.staff-error { margin: 16px 0 -8px; color: var(--error); font-size: .72rem; }

.staff-footer {
  min-height: 70px;
  padding: 20px 30px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
  color: #454c4e;
  border-top: 1px solid #171b1c;
  font-size: .65rem;
}
.staff-footer p { margin: 0; }
.staff-page-number { flex: 0 0 auto; font-family: Georgia, serif; letter-spacing: .1em; }

@media (max-width: 520px) {
  .staff-gate { min-height: calc(100vh - 92px); padding: 40px 18px; }
  .staff-panel { padding: 44px 23px 40px; }
  .staff-form { grid-template-columns: 1fr 72px; }
  .staff-footer { min-height: 92px; padding: 18px 20px; align-items: flex-start; flex-direction: column; gap: 8px; }
}