/* ===== デザインシステム ===== */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Noto+Sans+JP:wght@400;500;700&display=swap');

:root {
  /* カラーパレット */
  --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  --dark-bg: #0f0f23;
  --card-bg: rgba(255, 255, 255, 0.05);
  --card-border: rgba(255, 255, 255, 0.1);
  --text-primary: #ffffff;
  --text-secondary: #b4b4c8;
  --text-muted: #8b8b9f;
  --input-bg: rgba(255, 255, 255, 0.08);
  --input-border: rgba(255, 255, 255, 0.15);
  --input-focus: rgba(102, 126, 234, 0.3);

  /* タイポグラフィ */
  --font-primary: 'Inter', 'Noto Sans JP', sans-serif;
  --font-japanese: 'Noto Sans JP', sans-serif;

  /* スペーシング */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;

  /* ボーダー半径 */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;

  /* トランジション */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;

  /* シャドウ */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 20px rgba(102, 126, 234, 0.4);
}

/* ===== リセット & ベーススタイル ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  background: var(--dark-bg);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
}

/* 背景グラデーションアニメーション */
body::before {
  content: '';
  position: fixed;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 20% 50%, rgba(102, 126, 234, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(118, 75, 162, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 40% 20%, rgba(79, 172, 254, 0.1) 0%, transparent 50%);
  animation: backgroundShift 20s ease infinite;
  z-index: -1;
}

@keyframes backgroundShift {

  0%,
  100% {
    transform: translate(0, 0) rotate(0deg);
  }

  33% {
    transform: translate(-5%, 5%) rotate(5deg);
  }

  66% {
    transform: translate(5%, -5%) rotate(-5deg);
  }
}

/* ===== レイアウト ===== */
.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--spacing-lg);
}

/* ===== ヘッダー ===== */
.header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-xl) 0;
}

.header h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-sm);
  animation: fadeInDown 0.8s ease;
}

.header p {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  animation: fadeInUp 0.8s ease 0.2s both;
}

/* ===== メインコンテンツ ===== */
.main-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-lg);
  animation: fadeIn 1s ease 0.4s both;
}

@media (max-width: 1024px) {
  .main-content {
    grid-template-columns: 1fr;
  }
}

/* ===== カード ===== */
.card {
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.card-title {
  font-size: 1.75rem;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ===== フォーム ===== */
.form-group {
  margin-bottom: var(--spacing-md);
}

.form-label {
  display: block;
  font-weight: 500;
  margin-bottom: var(--spacing-xs);
  color: var(--text-secondary);
  font-size: 0.95rem;
  transition: color var(--transition-fast);
}

.form-input {
  width: 100%;
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: var(--radius-sm);
  padding: 0.75rem;
  color: var(--text-primary);
  font-family: var(--font-primary);
  font-size: 0.95rem;
  resize: vertical;
  min-height: 80px;
  transition: all var(--transition-fast);
}

.form-input:focus {
  outline: none;
  border-color: #667eea;
  box-shadow: 0 0 0 3px var(--input-focus);
  background: rgba(255, 255, 255, 0.1);
}

.form-input:hover {
  border-color: rgba(255, 255, 255, 0.25);
}

.form-input::placeholder {
  color: var(--text-muted);
}

/* ===== ボタン ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 1rem 2rem;
  font-size: 1.1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-normal);
  font-family: var(--font-primary);
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  transform: translate(-50%, -50%);
  transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

.btn-primary {
  background: var(--primary-gradient);
  color: white;
  box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text-primary);
  border: 1px solid var(--card-border);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.15);
  transform: translateY(-2px);
}

.btn-group {
  display: flex;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-md);
}

.btn-full {
  width: 100%;
}

/* ===== 出力エリア ===== */
.output-container {
  position: relative;
}

.output-area {
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  min-height: 400px;
  color: var(--text-primary);
  line-height: 1.8;
  font-size: 1rem;
  white-space: pre-wrap;
  word-wrap: break-word;
  position: relative;
}

.output-area.empty {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-style: italic;
}

.char-count {
  text-align: right;
  margin-top: var(--spacing-xs);
  font-size: 0.9rem;
  color: var(--text-muted);
}

.char-count.in-range {
  color: #4ade80;
}

/* ===== アニメーション ===== */
@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(-20px);
  }

  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.fade-in {
  animation: fadeIn var(--transition-normal);
}

/* ===== ローディングスピナー ===== */
.spinner {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 3px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  border-top-color: #fff;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* ===== トースト通知 ===== */
.toast {
  position: fixed;
  bottom: var(--spacing-lg);
  right: var(--spacing-lg);
  background: var(--primary-gradient);
  color: white;
  padding: 1rem 1.5rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  animation: slideInRight 0.3s ease;
  z-index: 1000;
}

@keyframes slideInRight {
  from {
    transform: translateX(400px);
    opacity: 0;
  }

  to {
    transform: translateX(0);
    opacity: 1;
  }
}

/* ===== レスポンシブ ===== */
@media (max-width: 768px) {
  .container {
    padding: var(--spacing-sm);
  }

  .header {
    padding: var(--spacing-md) 0;
  }

  .main-content {
    gap: var(--spacing-md);
  }

  .card {
    padding: var(--spacing-md);
  }

  .btn-group {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }
}

/* ===== アクセシビリティ ===== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* フォーカス表示 */
*:focus-visible {
  outline: 2px solid #667eea;
  outline-offset: 2px;
}

/* ===== フッター ===== */
.footer {
  text-align: center;
  margin-top: var(--spacing-xl);
  padding: var(--spacing-lg) 0;
}

.footer-btn {
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}