/* --- Base Styles --- */
:root {
  --bg-color: #0f1115;
  --card-bg: #1a1d23;
  --text-main: #e0e0e0;
  --text-dim: #888;
  --accent: #00e0b8; /* Neon Mint */
  --accent-dim: #00a88a;
  --danger: #ff4b5c;
  --border: #2c313a;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  margin: 0;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 900px;
  margin: 60px auto;
  padding: 0 20px;
}

/* --- Typography --- */
header {
  margin-bottom: 40px;
}

h1 {
  font-size: 2rem;
  letter-spacing: -0.02em;
  margin-bottom: 8px;
  font-weight: 700;
}

.highlight {
  color: var(--accent);
}

.subtitle {
  color: var(--text-dim);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* --- Toolbar & Controls --- */
.toolbar {
  background: var(--card-bg);
  padding: 20px;
  border-radius: 12px;
  border: 1px solid var(--border);
  margin-bottom: 20px;
}

.normalize-control {
  display: flex;
  gap: 24px;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
}

.select-wrapper {
  display: flex;
  align-items: center;
  gap: 10px;
}

#normalizeToggle {
  font-weight: 600;
  padding: 10px 24px;
  border-radius: 6px;
  border: 2px solid var(--border);
  background: transparent;
  color: var(--text-main);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

#normalizeToggle.normalize-on {
  background: var(--accent);
  border-color: var(--accent);
  color: #000;
  box-shadow: 0 0 20px rgba(0, 224, 184, 0.3);
}

select {
  background: var(--bg-color);
  color: var(--text-main);
  border: 1px solid var(--border);
  padding: 8px 12px;
  border-radius: 6px;
  outline: none;
}

/* --- Drop Zone --- */
#drop-zone {
  background: rgba(44, 49, 58, 0.2);
  border: 2px dashed var(--border);
  border-radius: 12px;
  padding: 60px 20px;
  transition: all 0.3s ease;
  cursor: pointer;
  margin-bottom: 40px;
  text-align: center;
}

#drop-zone:hover {
  border-color: var(--accent);
  background: rgba(0, 224, 184, 0.05);
}

.drop-icon {
  font-size: 2.5rem;
  color: var(--accent);
  display: block;
  margin-bottom: 10px;
}

.drop-sub {
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* --- Result Cards --- */
.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 24px;
  margin-bottom: 16px;
  text-align: left;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  position: relative;
  overflow: hidden;
}

.card:hover {
  transform: translateY(-2px);
  border-color: #444;
  box-shadow: 0 10px 20px rgba(0,0,0,0.3);
}

.wave {
  width: 100%;
  height: 100px;
  background: rgba(0, 0, 0, 0.2);
  border-radius: 6px;
  margin-top: 15px;
  cursor: pointer;
}

/* --- Action Buttons --- */
.action-bar {
  margin-top: 40px;
  text-align: center;
}

.stop-button {
  background: #222;
  color: var(--danger);
  border: 1px solid var(--danger);
  padding: 12px 40px;
  border-radius: 50px;
  font-weight: 700;
  letter-spacing: 0.05em;
  transition: all 0.3s ease;
}

.stop-button:hover {
  background: var(--danger);
  color: #fff;
  cursor: pointer;
}

/* --- Footer & Credits --- */
footer {
  margin-top: 80px;
  padding-bottom: 40px;
  border-top: 1px solid var(--border);
  text-align: center;
}

.credit {
  font-size: 0.75rem;
  margin-top: 30px;
  letter-spacing: 0.3em;
}

.credit a {
  color: var(--text-dim);
  text-decoration: none;
  transition: all 0.3s ease;
  display: inline-block;
  padding: 5px 10px;
}

.credit a:hover {
  color: var(--accent);
  text-shadow: 0 0 10px rgba(0, 224, 184, 0.5);
  letter-spacing: 0.4em;
}


/* --- SEO & Info Sections --- */
.seo-container {
  max-width: 750px;
  margin: 80px auto 0;
  text-align: left; /* 読みやすさのため左揃えに */
  border-top: 1px solid var(--border);
  padding-top: 40px;
}

.seo-item {
  margin-bottom: 32px;
}

.seo-item h2 {
  font-size: 1.1rem;
  color: var(--accent);
  margin-bottom: 12px;
  letter-spacing: 0.05em;
}

.seo-item p {
  font-size: 0.95rem;
  color: var(--text-dim);
  line-height: 1.8;
}

/* --- Note Box & Internal Links --- */
.note-box {
  background: rgba(255, 255, 255, 0.03);
  border-left: 3px solid var(--accent);
  padding: 24px 30px;
  border-radius: 0 8px 8px 0;
  margin-top: 50px;
}

.note-box h3 {
  font-size: 1rem;
  margin-top: 0;
  margin-bottom: 10px;
  color: var(--text-main);
}

.note-box p {
  font-size: 0.9rem;
  color: var(--text-dim);
  margin-bottom: 20px;
}

.tool-link {
  display: inline-block;
  color: var(--accent);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 600;
  border: 1px solid var(--accent);
  padding: 8px 18px;
  border-radius: 4px;
  transition: all 0.3s ease;
}

.tool-link:hover {
  background: var(--accent);
  color: #000;
  box-shadow: 0 0 15px rgba(0, 224, 184, 0.3);
}


/* --- How to Use Section --- */
.how-to-use {
  max-width: 900px;
  margin: 80px auto;
  text-align: left;
  border-top: 1px solid var(--border);
  padding-top: 60px;
}

.how-to-use h2 {
  font-size: 1.5rem;
  color: var(--text-main);
  text-align: center;
  margin-bottom: 10px;
}

.intro-desc {
  text-align: center;
  color: var(--text-dim);
  margin-bottom: 40px;
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
  margin-bottom: 40px;
}

.step-card {
  background: rgba(255, 255, 255, 0.02);
  padding: 24px;
  border-radius: 8px;
  border: 1px solid var(--border);
  position: relative;
}

.step-num {
  font-family: 'Courier New', Courier, monospace;
  color: var(--accent);
  font-weight: bold;
  font-size: 0.8rem;
  display: block;
  margin-bottom: 10px;
  opacity: 0.7;
}

.step-card h3 {
  font-size: 1rem;
  margin-bottom: 12px;
  color: var(--accent);
}

.step-card p {
  font-size: 0.85rem;
  color: var(--text-dim);
  line-height: 1.6;
}

.step-card strong {
  color: var(--text-main);
}

.about-tech {
  background: var(--card-bg);
  padding: 20px;
  border-radius: 6px;
  border: 1px dotted var(--border);
}

.about-tech p {
  font-size: 0.85rem;
  color: var(--text-dim);
  margin: 0;
  line-height: 1.6;
}

.header-flex {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
}

.lang-link {
  font-size: 12px;
  color: #888;
  text-decoration: none;
}

.lang-link:hover {
  color: #fff;
}

.tweet-btn {
    display: inline-block;
    font-size: 11px;
    font-weight: 600;
    color: #fff;
    background: linear-gradient(135deg, #1e293b, #0f172a);
    padding: 6px 14px;
    border-radius: 6px;
    transition: all 0.2s ease;
    border: 1px solid rgba(255,255,255,0.05);
}

.tweet-btn:hover {
    background: linear-gradient(135deg, #334155, #1e293b);
    transform: translateY(-1px);
}