:root {
  --bg: #f3f4f6;
  --card: #ffffff;
  --text: #111827;
  --muted: #4b5563;
  --border: #d1d5db;
  --focus: #2563eb;
  --focus-ring: rgba(37, 99, 235, 0.2);
  --danger: #dc2626;
  --success: #047857;
  --button: #1d4ed8;
  --button-hover: #1e40af;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  min-height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Noto Sans JP", sans-serif;
  background: var(--bg);
  color: var(--text);
}

.page-wrapper {
  min-height: 100vh;
  padding: 1rem;
  display: flex;
  align-items: flex-start;
  justify-content: center;
}

.feedback-card {
  width: 100%;
  max-width: 620px;
  background: var(--card);
  border-radius: 18px;
  padding: 1.25rem;
  box-shadow: 0 4px 20px rgba(17, 24, 39, 0.08);
  border: 1px solid #e5e7eb;
}

.card-header h1 {
  margin: 0;
  font-size: clamp(2rem, 4vw, 2.5rem);
  line-height: 1.2;
}

.card-header p {
  margin: 0.75rem 0 0;
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.8;
}

.feedback-form {
  margin-top: 1.5rem;
  display: grid;
  gap: 1.1rem;
}

.field {
  display: grid;
  gap: 0.45rem;
}

label {
  font-size: 0.95rem;
  font-weight: 650;
}

.required {
  color: var(--danger);
}

input,
select,
textarea,
button {
  font: inherit;
}

input,
select,
textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 0.75rem 0.9rem;
  font-size: 16px;
  line-height: 1.5;
  color: var(--text);
  background: #fff;
  transition: border-color 120ms ease, box-shadow 120ms ease;
}

input:focus,
select:focus,
textarea:focus {
  outline: none;
  border-color: var(--focus);
  box-shadow: 0 0 0 4px var(--focus-ring);
}

textarea {
  resize: vertical;
  min-height: 8rem;
}

button {
  border: 0;
  min-height: 3rem;
  border-radius: 12px;
  background: var(--button);
  color: #fff;
  font-weight: 700;
  font-size: 1rem;
  padding: 0.75rem 1rem;
  cursor: pointer;
  transition: background-color 120ms ease;
}

button:hover {
  background: var(--button-hover);
}

button:disabled {
  background: #9ca3af;
  cursor: not-allowed;
}

.help-message {
  margin: 0;
  font-size: 0.78rem;
  color: #6b7280;
}

.error-message {
  min-height: 1.2em;
  margin: 0;
  font-size: 0.85rem;
  color: var(--danger);
}

.result-message {
  margin: 0.2rem 0 0;
  min-height: 1.3rem;
  font-size: 0.95rem;
}

.result-message.success {
  color: var(--success);
}

.result-message.error {
  color: var(--danger);
}

.hp-field {
  position: absolute;
  left: -9999px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

@media (min-width: 640px) {
  .page-wrapper {
    padding: 2rem 1rem;
  }

  .feedback-card {
    padding: 1.8rem;
  }
}