* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
}

body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  background: #0b0c0f;
  color: #e5e7eb;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-height: 100vh;
  padding: 3rem 1rem;
}

.container {
  width: 100%;
  max-width: 640px;
  background: #14161b;
  border: 1px solid #23262d;
  border-radius: 14px;
  padding: 2rem;
}

h1 {
  margin: 0 0 0.4rem;
  font-size: 1.6rem;
  color: #f3f4f6;
}

.subtitle {
  margin: 0 0 1.5rem;
  color: #9ca3af;
}

label {
  display: block;
  margin-bottom: 1rem;
  font-size: 0.95rem;
  color: #d1d5db;
}

input[type="text"],
input[type="password"],
input[type="number"],
input[type="file"] {
  width: 100%;
  margin-top: 0.35rem;
  padding: 0.65rem 0.75rem;
  background: #0b0c0f;
  border: 1px solid #2f3542;
  color: #e5e7eb;
  border-radius: 8px;
  font-size: 1rem;
}

input[type="file"] {
  padding: 0.45rem;
}

input:focus {
  outline: none;
  border-color: #3b82f6;
}

.row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

button[type="submit"] {
  width: 100%;
  padding: 0.8rem;
  margin-top: 0.5rem;
  font-size: 1rem;
  font-weight: 600;
  color: #fff;
  background: #2563eb;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

button[type="submit"]:hover {
  background: #1d4ed8;
}

#result {
  margin-top: 1.25rem;
  padding: 1rem;
  background: #0b0c0f;
  border: 1px solid #23262d;
  border-radius: 10px;
}

#result p {
  margin: 0 0 0.5rem;
  color: #9ca3af;
}

#result .hint {
  margin: 0.5rem 0 0;
  font-size: 0.85rem;
  color: #6b7280;
}

.copy-row {
  display: flex;
  gap: 0.5rem;
}

.copy-row input {
  flex: 1;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.9rem;
}

.copy-row button {
  padding: 0 1rem;
  background: #374151;
  color: #fff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
}

.copy-row button:hover {
  background: #4b5563;
}

#status {
  margin: 1rem 0 0;
  min-height: 1.4rem;
}

#status.ok { color: #4ade80; }
#status.err { color: #f87171; }

#info { color: #9ca3af; }
#error {
  color: #f87171;
  margin-top: 1rem;
}

#holdGate {
  margin-top: 0.5rem;
  text-align: center;
}

#holdGate .warning {
  color: #9ca3af;
  font-size: 0.9rem;
  margin-bottom: 0.4rem;
}

#holdGate .hint {
  color: #6b7280;
  font-size: 0.82rem;
  margin-bottom: 1rem;
  line-height: 1.4;
}

#holdBtn {
  display: inline-block;
  width: 100%;
  max-width: 320px;
  padding: 1.2rem 1.5rem;
  font-size: 1.1rem;
  font-weight: 600;
  color: #fff;
  background: #2563eb;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  touch-action: manipulation;
  transition: background 0.15s ease, transform 0.05s ease;
}

#holdBtn:active {
  background: #1d4ed8;
  transform: scale(0.98);
}

.hidden { display: none !important; }

@media (max-width: 480px) {
  .row { grid-template-columns: 1fr; }
  body { padding: 1rem 0.75rem; }
  .container { padding: 1.25rem; }
  h1 { font-size: 1.35rem; }
  #canvasWrap { max-height: 52vh; }
  canvas { max-height: 52vh; width: auto; }
}