* { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg-primary: #f5f6fa;
  --bg-secondary: #fff;
  --text-primary: #1a1a2e;
  --text-secondary: #555;
  --text-light: #707070;
  --border-color: #e2e5ef;
  --shadow: rgba(0,0,0,0.06);
  --primary-color: #4a4a4f;
  --primary-light: rgba(74,74,79,0.08);
  --primary-glow: rgba(74,74,79,0.2);
  --gradient-primary: linear-gradient(135deg, #6b6b70, #1c1c1e);
  --btn-gradient: linear-gradient(135deg, #6b6b70, #1c1c1e);
  --danger-color: #ef4444;
  --danger-light: rgba(239,68,68,0.08);
  --success-color: #10b981;
  --transition: cubic-bezier(0.4, 0, 0.2, 1);
}

html.dark-mode,
body.dark-mode {
  --bg-primary: #18181b;
  --bg-secondary: #1f1f23;
  --btn-gradient: linear-gradient(135deg, #b0b0b5, #4a4a4f);
  --gradient-primary: linear-gradient(135deg, #b0b0b5, #4a4a4f);
  --text-primary: #eaeaf2;
  --text-secondary: #a0a0b8;
  --text-light: #8686ab;
  --border-color: #2e2e33;
  --shadow: rgba(0,0,0,0.35);
  --primary-color: #b0b0b5;
  --primary-light: rgba(176,176,181,0.12);
  --primary-glow: rgba(176,176,181,0.3);
  --danger-light: rgba(239,68,68,0.12);
}

body {
  font-family: 'Inter', 'Segoe UI', -apple-system, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  transition: background-color 0.3s ease, border-color 0.3s ease, color 0.3s ease;
}

body :where(*) {
  transition: background-color 0.3s ease, border-color 0.3s ease, color 0.3s ease;
}

.container {
  max-width: 700px;
  margin: 0 auto;
  padding: 36px 24px 60px;
  position: relative;
  z-index: 1;
}

/* ── Header (기존 도구 페이지와 동일한 구조) ── */
header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 32px;
  gap: 20px;
}

.header-left { flex: 1; }

.home-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.82rem;
  color: #4a4a4f;
  text-decoration: none;
  margin-bottom: 10px;
  font-weight: 600;
  padding: 4px 12px 4px 8px;
  border-radius: 20px;
  background: var(--primary-light);
  transition: all 0.25s var(--transition);
}

html.dark-mode .home-link,
body.dark-mode .home-link {
  color: #b0b0b5;
}

.home-link-icon { flex-shrink: 0; border-radius: 4px; }

.home-link:hover {
  background: var(--primary-glow);
  transform: translateX(-3px);
}

.header-left h1 {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -1px;
  margin-bottom: 6px;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.subtitle {
  font-size: 0.88rem;
  color: var(--text-secondary);
  font-weight: 400;
}

.header-right { display: flex; align-items: center; gap: 10px; }

.icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  padding: 0;
  border: 1.5px solid var(--border-color);
  border-radius: 10px;
  background: var(--bg-primary);
  cursor: pointer;
  transition: all 0.25s var(--transition);
  color: var(--text-secondary);
}

.icon-btn:hover {
  border-color: var(--primary-color);
  background: var(--primary-light);
  color: var(--primary-color);
}

.theme-icon { width: 18px; height: 18px; }

.lang-select { position: relative; }

.lang-toggle {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  min-width: 160px;
  padding: 6px;
  border: 1.5px solid var(--border-color);
  border-radius: 12px;
  background: var(--bg-secondary);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 8px 24px var(--shadow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-6px);
  transition: all 0.2s var(--transition);
  z-index: 200;
}

.lang-select.open .lang-toggle {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.lang-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  border: none;
  background: none;
  cursor: pointer;
  font-family: inherit;
  font-size: 0.86rem;
  font-weight: 600;
  color: var(--text-secondary);
  padding: 9px 10px;
  border-radius: 8px;
  transition: all 0.2s var(--transition);
}

.lang-option:hover { background: var(--primary-light); color: var(--primary-color); }
.lang-option.active { color: var(--primary-color); }
.lang-option .lang-check { opacity: 0; color: var(--primary-color); }
.lang-option.active .lang-check { opacity: 1; }

/* ── JSON 입력/출력 ── */
.json-textarea {
  width: 100%;
  min-height: 260px;
  padding: 12px 14px;
  border: 1.5px solid var(--border-color);
  border-radius: 12px;
  font-family: var(--font-mono, ui-monospace, monospace);
  font-size: 0.85rem;
  line-height: 1.6;
  background: var(--bg-primary);
  color: var(--text-primary);
  outline: none;
  resize: vertical;
  tab-size: 2;
  transition: border-color 0.2s;
}

.json-textarea:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px var(--primary-light);
}

.json-meta {
  margin-top: 8px;
  font-size: 0.78rem;
  color: var(--text-secondary);
}

.json-btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

.json-btn-row .action-btn,
.json-btn-row .btn-primary {
  flex: 1;
  min-width: 120px;
  text-align: center;
  justify-content: center;
}

.result-actions {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 16px;
}

/* ── Input Panel ── */
.input-panel {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  padding: 24px;
  margin-bottom: 24px;
  box-shadow: 0 2px 8px var(--shadow);
}

.input-row {
  display: flex;
  gap: 12px;
  align-items: flex-end;
  flex-wrap: wrap;
}

.input-group {
  flex: 1;
  min-width: 140px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.input-group label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.3px;
}

.input-group input {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--border-color);
  border-radius: 10px;
  font-size: 0.9rem;
  font-family: inherit;
  background: var(--bg-primary);
  color: var(--text-primary);
  outline: none;
  transition: border-color 0.2s;
}

.input-group input:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px var(--primary-light);
}

.form-hint {
  margin-top: 12px;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.btn-primary {
  padding: 10px 24px;
  background: var(--btn-gradient);
  color: #fff;
  border: none;
  border-radius: 10px;
  font-size: 0.88rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.25s var(--transition);
  box-shadow: 0 3px 12px var(--primary-glow);
  white-space: nowrap;
}

.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 20px var(--primary-glow); }
.btn-primary:active { transform: translateY(0) scale(0.97); }

.action-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border: 1.5px solid var(--border-color);
  border-radius: 10px;
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font-size: 0.82rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.25s var(--transition);
}

.action-btn:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
  background: var(--primary-light);
}

/* ── 경고 배너 (미래 날짜/잘못된 날짜) ── */
.warning-banner {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  border-radius: 12px;
  background: var(--danger-light);
  color: var(--danger-color);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 20px;
}

/* ── 결과 카드 ── */
.result-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 18px;
  padding: 32px 24px;
  margin-bottom: 24px;
  box-shadow: 0 2px 8px var(--shadow);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.result-main {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 10px;
  margin-bottom: 24px;
}

.result-big {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -1px;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.result-big-label {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 16px;
}

.result-item {
  background: var(--bg-primary);
  border-radius: 12px;
  padding: 14px 8px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.result-value {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
}

.result-label {
  font-size: 0.72rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.result-note {
  font-size: 0.78rem;
  color: var(--text-light);
  margin-bottom: 16px;
  line-height: 1.5;
}

.result-actions {
  display: flex;
  justify-content: center;
  gap: 8px;
}

/* ── Modal ── */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.45);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  animation: fadeBg 0.2s ease;
  padding: 20px;
}

@keyframes fadeBg { from { opacity: 0; } to { opacity: 1; } }

.modal-box {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-radius: 20px;
  padding: 28px;
  width: 100%;
  max-width: 400px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.2);
  animation: modalIn 0.35s var(--transition);
  border: 1px solid var(--border-color);
  position: relative;
  overflow: hidden;
}

.modal-box::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--gradient-primary);
}

@keyframes modalIn {
  from { transform: translateY(24px) scale(0.95); opacity: 0; }
  to   { transform: translateY(0) scale(1); opacity: 1; }
}

.modal-box h2 { margin-bottom: 18px; font-size: 1.3rem; font-weight: 700; letter-spacing: -0.5px; }

.shortcuts { display: flex; flex-direction: column; gap: 10px; margin-bottom: 20px; }

.shortcut-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.88rem;
  padding: 8px 12px;
  background: var(--bg-primary);
  border-radius: 10px;
}

.shortcut-item kbd {
  background: var(--gradient-primary);
  color: #fff;
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 0.72rem;
  font-weight: 700;
  font-family: 'Inter', monospace;
  box-shadow: 0 2px 6px var(--primary-glow);
  letter-spacing: 0.3px;
}

.shortcut-item span { color: var(--text-secondary); font-weight: 500; }

.modal-close-btn {
  width: 100%;
  background: var(--btn-gradient);
  color: #fff;
  border: none;
  border-radius: 12px;
  padding: 12px;
  font-size: 0.92rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.25s;
  box-shadow: 0 3px 10px var(--primary-glow);
}

.modal-close-btn:hover { transform: translateY(-2px); box-shadow: 0 6px 18px var(--primary-glow); }

/* ── Toast ── */
.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--bg-secondary);
  color: var(--text-primary);
  padding: 12px 24px;
  border-radius: 12px;
  font-size: 0.85rem;
  font-weight: 600;
  z-index: 200;
  box-shadow: 0 8px 30px rgba(0,0,0,0.15);
  border: 1px solid var(--border-color);
  animation: toastIn 0.35s var(--transition);
}

@keyframes toastIn {
  from { transform: translateX(-50%) translateY(16px); opacity: 0; }
  to   { transform: translateX(-50%) translateY(0); opacity: 1; }
}

/* ── Scrollbar / focus ── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-color); border-radius: 6px; }
::selection { background: var(--primary-glow); }
*:focus-visible { outline: 2px solid var(--primary-color); outline-offset: 2px; }
html { overflow-x: hidden; }

/* ── Responsive ── */
@media (max-width: 600px) {
  .container { padding: 24px 16px 50px; }
  .header-left h1 { font-size: 1.5rem; }
  .lang-toggle { min-width: 140px; right: -4px; }
  .lang-option { padding: 8px 8px; font-size: 0.8rem; }
  .input-row { flex-direction: column; align-items: stretch; }
  .input-row .btn-primary { width: 100%; }
  .result-big { font-size: 2.2rem; }
  .result-grid { grid-template-columns: 1fr; }
}