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

body {
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #101010;
  color: #f5f5f5;
}

.app {
  max-width: 960px;
  margin: 24px auto 48px;
  padding: 24px;
  background: #181818;
  border-radius: 16px;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.45);
}

header h1 {
  margin: 0 0 4px;
  font-size: 1.7rem;
}

header p {
  margin: 0 0 16px;
  color: #bbbbbb;
}

.controls {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

label {
  font-size: 0.9rem;
  color: #dddddd;
}

input[type="text"],
input[type="file"] {
  padding: 6px 10px;
  border-radius: 8px;
  border: 1px solid #444;
  background: #101010;
  color: #f5f5f5;
  font-size: 0.95rem;
}

input[type="file"] {
  padding: 4px 6px;
  background: #111;
}

input[type="text"]:focus {
  outline: none;
  border-color: #6ab3ff;
}

button {
  padding: 8px 14px;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  margin-right: 8px;
}

#refreshBtn {
  background: #3a9cff;
  color: white;
}

#downloadPngBtn {
  background: #f5f5f5;
  color: #101010;
}

button:hover {
  opacity: 0.92;
}

.help {
  font-size: 0.8rem;
  color: #999;
}

.note {
  grid-column: 1 / -1;
  font-size: 0.8rem;
  color: #aaaaaa;
}

.buttons {
  flex-direction: row;
  align-items: center;
}

.preview-wrapper h2 {
  margin-top: 0;
  font-size: 1.1rem;
  margin-bottom: 12px;
}

.preview-wrapper {
  margin-top: 8px;
}

.signature-block {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 18px 22px;
  background: #ffffff;
  color: #000000;
  border-radius: 12px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
  min-width: 420px;
}

.wk-logo {
  max-width: 200px;
  margin-bottom: 10px;
}

.signature-image {
  max-width: 260px;
  margin-bottom: 4px;
}

.text-line {
  line-height: 1.25;
  text-align: center;
}

.label {
  font-size: 0.85rem;
}

.name {
  font-weight: 700;
  font-size: 1rem;
}

.timestamp {
  font-size: 0.8rem;
}

footer {
  margin-top: 24px;
  font-size: 0.8rem;
  color: #9c9c9c;
}