body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  margin: 0;
  background: #f5f5f7;
}

/* Card */

.card {
  background: white;
  width: 100%;
  min-height: 100vh;
  padding: 2rem 1.5rem;
  box-sizing: border-box;
}

/* Typography scaled up ~60% */

h1 {
  margin: 0;
  font-size: 2.2rem;
  font-weight: 700;
}

.subtitle {
  margin-top: 0.5rem;
  font-size: 1.1rem;
  color: #666;
  margin-bottom: 2rem;
}

/* Tabs */

.tabs {
  display: flex;
  border-radius: 14px;
  overflow: hidden;
  background: #ececec;
  margin-bottom: 2rem;
}

.tabs button {
  flex: 1;
  padding: 1rem;
  border: none;
  background: transparent;
  cursor: pointer;
  font-weight: 600;
  font-size: 1.05rem;
}

.tabs button.active {
  background: #111;
  color: white;
}

/* Content */

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

.field {
  font-size: 1.1rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid #eee;
  word-break: break-word;
}

/* Button */

.button {
  display: block;
  margin-top: 2rem;
  padding: 1.2rem;
  border-radius: 14px;
  text-align: center;
  text-decoration: none;
  background: #111;
  color: white;
  font-weight: 600;
  font-size: 1.2rem;
}

/* Desktop only: constrain width */

@media (min-width: 768px) {
  body {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
  }

  .card {
    max-width: 520px;
    min-height: auto;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.12);
  }
}