body {
  margin: 0;
  background: #f4f6f8;
  color: #1f2937;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.container {
  max-width: 880px;
  margin: 40px auto;
  padding: 0 16px;
}

.card {
  background: #ffffff;
  border-radius: 16px;
  padding: 32px;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.08);
}

h1 {
  margin-top: 0;
  font-size: 28px;
}

h2 {
  margin-top: 32px;
  font-size: 20px;
}

.lead {
  color: #64748b;
}

.form-group {
  margin: 20px 0;
}

label {
  display: block;
  margin-bottom: 8px;
  font-weight: 700;
}

input {
  width: 100%;
  box-sizing: border-box;
  padding: 12px;
  border: 1px solid #cbd5e1;
  border-radius: 10px;
  font-size: 16px;
}

button,
.button-link {
  display: inline-block;
  border: 0;
  border-radius: 10px;
  padding: 12px 18px;
  background: #2563eb;
  color: #ffffff;
  text-decoration: none;
  font-weight: 700;
  cursor: pointer;
}

button:disabled {
  background: #94a3b8;
  cursor: not-allowed;
}

.note {
  color: #64748b;
  font-size: 14px;
}

.url-box {
  margin-top: 8px;
  font-family: monospace;
}

.info-box,
.auth-box {
  margin: 24px 0;
  padding: 20px;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 12px;
}

.summary {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin: 24px 0;
}

.summary div {
  padding: 16px;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 12px;
}

.summary span {
  display: block;
  color: #64748b;
  font-size: 13px;
  margin-bottom: 6px;
}

.summary strong {
  font-size: 16px;
}

.file-card {
  margin: 16px 0;
  padding: 18px;
  border: 1px solid #e2e8f0;
  border-radius: 12px;
  background: #ffffff;
}

.file-name {
  font-weight: 800;
  font-size: 18px;
}

.file-meta {
  margin-top: 8px;
  color: #475569;
}

@media (max-width: 640px) {
  .summary {
    grid-template-columns: 1fr;
  }

  .card {
    padding: 22px;
  }
}
button,
input[type="submit"] {
  width: 100%;
  padding: 15px;
  border: none;
  border-radius: 999px;
  background: linear-gradient(135deg, #2f7df6, #1f5edb);
  color: #fff;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition:
    transform 0.25s ease,
    box-shadow 0.25s ease,
    background 0.25s ease;
}

/* ホバー時 */
button:hover,
input[type="submit"]:hover {
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 14px 30px rgba(47, 125, 246, 0.35);
}

/* 押した時 */
button:active,
input[type="submit"]:active {
  transform: scale(0.97);
}

/* 光が流れる演出 */
button::before,
input[type="submit"]::before {
  content: "";
  position: absolute;
  top: 0;
  left: -75%;
  width: 50%;
  height: 100%;
  background: rgba(255,255,255,0.35);
  transform: skewX(-25deg);
  transition: 0.7s;
}

/* hoverで光を流す */
button:hover::before,
input[type="submit"]:hover::before {
  left: 130%;
}