:root{
  --bg:#0b1020;
  --card: rgba(255,255,255,0.05);
  --text:#e6eef8;
  --muted:#9aa7bf;
  --accent:linear-gradient(90deg, #667eea 0%, #764ba2 100%);
  --glass: rgba(255,255,255,0.04);
  --radius:18px;
}

*{box-sizing:border-box}
html,body{height:100%}

body{
  margin:0;
  font-family: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
               "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Yu Gothic", "Meiryo", sans-serif;
  background: var(--bg);
  color:var(--text);
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

.center{
  min-height:100vh;
  display:flex;
  align-items:center;
  justify-content:center;
  flex-direction:column;
  gap:16px;
  padding:24px;
}

.clock-card{
  background:
    linear-gradient(
      180deg,
      rgba(255,255,255,0.08),
      rgba(255,255,255,0.02)
    );
  backdrop-filter: blur(8px);
  border-radius:var(--radius);
  padding:28px 36px;
  box-shadow: 0 20px 40px rgba(0,0,0,0.45);
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:10px;
  width:min(92vw, 420px);
  border: 1px solid rgba(255,255,255,0.08);
}

.clock{
  display:flex;
  align-items:baseline;
  gap:8px;
  user-select:none;
}

#time{
  font-family: "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, Monaco, "Courier New", monospace;
  font-weight:700;
  line-height:1;
  font-size: clamp(40px, 10vw, 72px);
  letter-spacing: -0.02em;
  color:var(--text);
  white-space:nowrap;
}

.colon{
  display:inline-block;
  animation: blink 1s steps(1,start) infinite;
  vertical-align: middle;
  opacity:1;
}

.date{
  font-size:14px;
  color:var(--muted);
  font-weight:500;
}

@media (max-width:420px){
  .clock-card{ padding:20px }
  #time{ font-size: clamp(36px, 12vw, 60px); }
}