:root {
  --color-primary: #4a6cf7;
  --color-primary-dark: #3450c4;
  --color-secondary: #f0f2fa;
  --color-text: #1f2333;
  --color-text-muted: #6b7280;
  --color-border: #e0e3ec;
  --color-error: #e0433f;
  --color-success: #1f9d55;
  --radius: 14px;
  --max-width: 480px;
}

* {
  box-sizing: border-box;
}

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

body {
  font-family: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic",
    "Meiryo", -apple-system, BlinkMacSystemFont, sans-serif;
  background: linear-gradient(180deg, #eef1fb 0%, #fafbff 100%);
  color: var(--color-text);
  min-height: 100vh;
  line-height: 1.6;
}

.app {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 24px 20px 48px;
  min-height: 100vh;
}

.screen {
  display: none;
}

.screen.active {
  display: block;
  animation: fade-in 0.2s ease-out;
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.app-header {
  position: relative;
  text-align: center;
  margin-bottom: 24px;
}

.app-header h1 {
  font-size: 1.4rem;
  margin: 8px 0 4px;
}

.app-header .lead {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin: 0;
}

.btn-back {
  position: absolute;
  left: 0;
  top: 0;
  background: none;
  border: none;
  color: var(--color-primary);
  font-size: 0.95rem;
  padding: 6px 4px;
  cursor: pointer;
}

.card {
  background: #fff;
  border-radius: var(--radius);
  padding: 18px 16px;
  box-shadow: 0 2px 10px rgba(30, 40, 90, 0.06);
  margin-bottom: 24px;
}

.field-label {
  display: block;
  font-size: 0.88rem;
  color: var(--color-text-muted);
  margin-bottom: 8px;
}

.text-input {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  font-size: 1rem;
  background: #fafbff;
}

.text-input:focus {
  outline: none;
  border-color: var(--color-primary);
}

.mode-buttons {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.btn {
  border: none;
  border-radius: 12px;
  padding: 14px 16px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.05s ease, opacity 0.15s ease;
}

.btn:active {
  transform: scale(0.98);
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-large {
  width: 100%;
  padding: 16px;
  font-size: 1.05rem;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
}

.btn-secondary {
  background: var(--color-secondary);
  color: var(--color-primary-dark);
}

.question-form {
  display: flex;
  flex-direction: column;
  gap: 22px;
}

.question {
  border: none;
  margin: 0;
  padding: 0;
}

.question legend {
  font-weight: 600;
  font-size: 0.98rem;
  margin-bottom: 10px;
  padding: 0;
}

.option-card {
  display: flex;
  align-items: center;
  gap: 10px;
  background: #fff;
  border: 1.5px solid var(--color-border);
  border-radius: 12px;
  padding: 14px;
  margin-bottom: 8px;
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.option-card input {
  width: 18px;
  height: 18px;
  accent-color: var(--color-primary);
  flex-shrink: 0;
}

.option-card:has(input:checked) {
  border-color: var(--color-primary);
  background: #f3f5ff;
}

.option-card span {
  font-size: 0.95rem;
}

.error-message {
  color: var(--color-error);
  font-size: 0.88rem;
  margin: 0;
  text-align: center;
}

.btn-submit {
  margin-top: 4px;
}

.thanks-message {
  text-align: center;
  padding: 40px 16px;
}

.thanks-message p {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-success);
  margin-bottom: 20px;
}