/* ── Variables ──────────────────────────────────────────────────────────────── */

:root {
  --bg:       #0f1115;
  --panel:    #171a21;
  --panel-2:  #1e222b;
  --fg:       #e6e8ec;
  --muted:    #8a93a6;
  --accent:   #f5c26b;
  --accent-2: #74c7ec;
  --border:   #272b35;
  --error:    #ff6b6b;
  --success:  #a6e3a1;
  --radius:   10px;
}

[data-theme="light"] {
  --bg:      #f5f5f7;
  --panel:   #ffffff;
  --panel-2: #ebebed;
  --fg:      #1a1a1f;
  --muted:   #6e7585;
  --accent:  #d97706;
  --accent-2:#0284c7;
  --border:  #d1d5db;
  --error:   #dc2626;
  --success: #16a34a;
}

/* ── Reset ──────────────────────────────────────────────────────────────────── */

*, *::before, *::after { box-sizing: border-box; }

html, body {
  margin: 0; padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans",
    "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  font-size: 15px;
  line-height: 1.6;
  transition: background 0.2s, color 0.2s;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ── Header ─────────────────────────────────────────────────────────────────── */

header {
  padding: 20px 28px 16px;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  border-bottom: 1px solid var(--border);
}

.header-title h1 {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--accent);
}

.header-title .subtitle {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-shrink: 0;
}

/* ── Theme toggle ───────────────────────────────────────────────────────────── */

.theme-control {
  display: flex;
  align-items: center;
  gap: 6px;
}

.theme-icon { font-size: 14px; user-select: none; }

.toggle-switch {
  position: relative;
  display: inline-block;
  width: 36px;
  height: 20px;
}

.toggle-switch input { opacity: 0; width: 0; height: 0; }

.slider {
  position: absolute;
  inset: 0;
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 20px;
  cursor: pointer;
  transition: background 0.2s;
}

.slider::before {
  content: '';
  position: absolute;
  width: 14px; height: 14px;
  top: 2px; left: 2px;
  background: var(--muted);
  border-radius: 50%;
  transition: transform 0.2s, background 0.2s;
}

.toggle-switch input:checked + .slider { background: var(--accent); }
.toggle-switch input:checked + .slider::before {
  transform: translateX(16px);
  background: #fff;
}

/* ── Language selector ──────────────────────────────────────────────────────── */

.lang-control select {
  background: var(--panel-2);
  border: 1px solid var(--border);
  color: var(--fg);
  padding: 4px 8px;
  border-radius: 6px;
  font-size: 13px;
  cursor: pointer;
}

/* ── Main ───────────────────────────────────────────────────────────────────── */

main {
  padding: 24px 28px 48px;
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

section { margin: 0; }

h2 {
  font-size: 11px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 600;
  margin: 0 0 10px;
}

/* ── Mode toggle ────────────────────────────────────────────────────────────── */

.mode-section { margin: 0; }

.mode-toggle {
  display: flex;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 4px;
  gap: 4px;
}

.mode-btn {
  flex: 1;
  padding: 10px 16px;
  background: transparent;
  border: none;
  border-radius: 7px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.mode-btn:hover { background: var(--panel-2); color: var(--fg); }

.mode-btn.active {
  background: var(--accent);
  color: #1a1207;
}

/* ── System selector ────────────────────────────────────────────────────────── */

.radio-group {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.radio-label {
  display: flex;
  align-items: center;
  gap: 7px;
  cursor: pointer;
  padding: 8px 14px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  transition: border-color 0.15s, background 0.15s;
}

.radio-label:hover { border-color: var(--accent); }

.radio-label input[type="radio"] { accent-color: var(--accent); }

.radio-label:has(input:checked) {
  border-color: var(--accent);
  background: var(--panel-2);
}

/* ── Input ──────────────────────────────────────────────────────────────────── */

.input-section label {
  display: block;
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 8px;
}

#main-input {
  width: 100%;
  padding: 14px 18px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--fg);
  font-size: 20px;
  font-family: "SF Mono", Menlo, Consolas, "Hiragino Kaku Gothic ProN", monospace;
  outline: none;
  transition: border-color 0.15s;
}

#main-input:focus { border-color: var(--accent); }
#main-input::placeholder { color: var(--muted); }

/* ── Output ─────────────────────────────────────────────────────────────────── */

.output-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}

.output-header h2 { margin: 0; }

.copy-btn {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--muted);
  font-size: 12px;
  padding: 4px 10px;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}

.copy-btn:hover { color: var(--fg); border-color: var(--accent); }

.output-display {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  min-height: 64px;
  font-size: 28px;
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "游明朝", Georgia, serif;
  letter-spacing: 0.06em;
  color: var(--accent);
  word-break: break-all;
}

.output-display.error {
  color: var(--error);
  font-size: 14px;
  font-family: inherit;
}

/* ── Yen section ────────────────────────────────────────────────────────────── */

.yen-rows {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.yen-row {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 16px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.yen-row-label {
  font-size: 11px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.yen-value {
  font-size: 16px;
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "游明朝", Georgia, serif;
  color: var(--fg);
  word-break: break-all;
}

.yen-legal-val {
  color: var(--accent-2);
}

/* ── Examples ───────────────────────────────────────────────────────────────── */

.examples-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 8px;
}

.example-card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  cursor: pointer;
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 4px;
  transition: border-color 0.15s, background 0.15s;
}

.example-card:hover {
  border-color: var(--accent);
  background: var(--panel-2);
}

.example-label {
  font-size: 12px;
  color: var(--muted);
  font-family: "SF Mono", Menlo, Consolas, monospace;
}

.example-kan {
  font-size: 15px;
  font-family: "Hiragino Mincho ProN", "Yu Mincho", "游明朝", Georgia, serif;
  color: var(--fg);
  word-break: break-all;
}

/* ── Footer ─────────────────────────────────────────────────────────────────── */

footer {
  text-align: center;
  padding: 24px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 13px;
}

/* ── Responsive ─────────────────────────────────────────────────────────────── */

@media (max-width: 600px) {
  header { flex-direction: column; gap: 12px; }
  main { padding: 16px 16px 40px; gap: 18px; }
  .header-title h1 { font-size: 18px; }
  .output-display { font-size: 22px; }
  .examples-grid { grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); }
  .mode-btn { font-size: 13px; padding: 9px 10px; }
}