* { 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;
  --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);
}

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;
}

body::before {
  content: '';
  position: fixed;
  top: -200px;
  right: -200px;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(74,74,79,0.07) 0%, transparent 65%);
  pointer-events: none;
}

.container {
  max-width: 760px;
  margin: 0 auto;
  padding: 36px 24px 60px;
  position: relative;
  z-index: 1;
}

/* ── Header ── */
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);
  transform: none;
  box-shadow: none;
}

.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;
}

/* ── 탭 네비게이션 ── */
.tab-nav {
  display: flex;
  gap: 8px;
  margin-bottom: 24px;
}

.tab-btn {
  flex: 1;
  padding: 11px 14px;
  border: 1.5px solid var(--border-color);
  border-radius: 12px;
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font-family: inherit;
  font-size: 0.86rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.25s var(--transition);
}

.tab-btn:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
}

.tab-btn.active {
  background: var(--gradient-primary);
  border-color: transparent;
  color: #fff;
  box-shadow: 0 4px 14px var(--primary-glow);
}

/* ── 변환기 탭 ── */
.hex-input-row {
  margin-bottom: 20px;
}

.hex-input-row label {
  display: block;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-light);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 8px;
}

#hex-input {
  width: 100%;
  padding: 14px 16px;
  border: 2px solid var(--border-color);
  border-radius: 12px;
  font-size: 1.3rem;
  font-family: 'Inter', monospace;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  background: var(--bg-secondary);
  color: var(--text-primary);
  outline: none;
  transition: all 0.25s var(--transition);
}

#hex-input:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 4px var(--primary-light);
}

#hex-input.invalid {
  border-color: var(--danger-color);
}

.color-preview {
  height: 140px;
  border-radius: 16px;
  border: 1px solid var(--border-color);
  margin-bottom: 20px;
  transition: background-color 0.2s;
}

.value-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 8px;
  position: relative; /* 절대배치 자식 기준점 — .fold-corner는 이제 background로 그려서 필요 없음 */
}

.value-row {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 10px 12px 10px 16px;
}

.value-label {
  width: 40px;
  flex-shrink: 0;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-light);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.value-text {
  flex: 1;
  font-family: 'Inter', monospace;
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--text-primary);
  word-break: break-all;
}

.copy-icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  flex-shrink: 0;
  border: 1.5px solid var(--border-color);
  border-radius: 9px;
  background: var(--bg-primary);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.25s var(--transition);
}

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

.copy-icon-btn svg {
  width: 15px;
  height: 15px;
}

/* ── 팔레트 탭 ── */
.palette-actions {
  display: flex;
  justify-content: center;
  margin-bottom: 20px;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--btn-gradient);
  color: #fff;
  border: none;
  border-radius: 12px;
  padding: 13px 32px;
  font-size: 0.92rem;
  font-family: inherit;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 4px 14px var(--primary-glow);
  transition: all 0.25s var(--transition);
}

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

.btn-primary:active {
  transform: translateY(0) scale(0.98);
}

.palette-row {
  display: flex;
  gap: 0;
  border-radius: 16px;
  overflow: hidden;
  border: 1px solid var(--border-color);
  min-height: 180px;
}

.palette-empty {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 20px;
  color: var(--text-light);
  font-size: 0.88rem;
  text-align: center;
}

.swatch {
  flex: 1;
  border: none;
  border-left: 1px solid rgba(255,255,255,0.15);
  cursor: pointer;
  position: relative;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding-bottom: 14px;
  transition: flex-grow 0.25s var(--transition);
}

.swatch:first-child { border-left: none; }

.swatch:hover {
  flex-grow: 1.4;
}

.swatch-hex {
  background: rgba(0,0,0,0.4);
  color: #fff;
  font-family: 'Inter', monospace;
  font-weight: 700;
  font-size: 0.72rem;
  padding: 4px 8px;
  border-radius: 6px;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  white-space: nowrap;
}

/* ── 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;
  transition: background 0.2s;
}

.shortcut-item:hover {
  background: var(--primary-light);
}

.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%) translateY(0);
  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 ── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-color); border-radius: 6px; }

::selection {
  background: var(--primary-glow);
  color: var(--text-primary);
}

*:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* ── 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; }

  .tab-btn { font-size: 0.8rem; padding: 10px 8px; }

  .color-preview { height: 100px; }

  #hex-input { font-size: 1.1rem; padding: 12px 14px; }

  .palette-row { flex-direction: column; min-height: 0; }
  .swatch { min-height: 56px; border-left: none; border-top: 1px solid rgba(255,255,255,0.15); }
  .swatch:first-child { border-top: none; }
  .swatch:hover { flex-grow: 1; }
}

/* 모바일 가로 스크롤 방지 */
html { overflow-x: hidden; }