/* -------------------------------------------------------------
 * Custom Design System: UtilAll Premium CSS
 * ------------------------------------------------------------- */

/* Reset & Variables */
/* Light Theme (Default - 10% Darker for eye comfort) */
:root {
  --bg-dark: #d1d7e0;
  --bg-card: rgba(255, 255, 255, 0.45);
  --bg-card-hover: rgba(255, 255, 255, 0.65);
  --bg-sidebar: rgba(203, 213, 225, 0.85);
  --bg-display: rgba(15, 23, 42, 0.07);
  
  --accent-cyan: #0891b2;
  --accent-cyan-rgb: 8, 145, 178;
  --accent-blue: #2563eb;
  --accent-purple: #7c3aed;
  --accent-coral: #dc2626;
  
  --text-primary: #0f172a;
  --text-muted: #334155;
  --text-dark: #f8fafc;
  
  --border-glass: rgba(15, 23, 42, 0.12);
  --border-focus: rgba(8, 145, 178, 0.5);
  
  --glow-cyan: 0 0 20px rgba(8, 145, 178, 0.15);
  --glow-blue: 0 0 20px rgba(37, 99, 235, 0.15);
  
  --font-main: 'Outfit', 'Noto Sans KR', sans-serif;
  --font-mono: 'Space Mono', monospace;
  
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: all 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  --bg-glow-opacity: 0.18;
}

/* Dark Theme */
body.dark-theme {
  --bg-dark: #090d16;
  --bg-card: rgba(20, 26, 42, 0.45);
  --bg-card-hover: rgba(28, 38, 62, 0.6);
  --bg-sidebar: rgba(11, 16, 28, 0.8);
  --bg-display: rgba(0, 0, 0, 0.35);
  
  --accent-cyan: #00f2fe;
  --accent-cyan-rgb: 0, 242, 254;
  --accent-blue: #4facfe;
  --accent-purple: #9b51e0;
  --accent-coral: #ff758c;
  
  --text-primary: #f1f5f9;
  --text-muted: #94a3b8;
  --text-dark: #0f172a;
  
  --border-glass: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(0, 242, 254, 0.5);
  
  --glow-cyan: 0 0 20px rgba(0, 242, 254, 0.25);
  --glow-blue: 0 0 20px rgba(79, 172, 254, 0.25);
  --bg-glow-opacity: 0.25;
}

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

body {
  font-family: var(--font-main);
  background-color: var(--bg-dark);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
  transition: background-color 0.4s ease, color 0.4s ease;
}

/* Background Glow Effects */
.bg-glow {
  position: fixed;
  width: 40vw;
  height: 40vw;
  border-radius: 50%;
  filter: blur(120px);
  z-index: -1;
  opacity: var(--bg-glow-opacity);
  pointer-events: none;
  animation: glow-float 20s infinite alternate;
  transition: opacity 0.4s ease;
}

.bg-glow-1 {
  background: radial-gradient(circle, var(--accent-cyan) 0%, transparent 70%);
  top: -10%;
  left: -10%;
}

.bg-glow-2 {
  background: radial-gradient(circle, var(--accent-purple) 0%, transparent 70%);
  bottom: -10%;
  right: -10%;
  animation-delay: -5s;
}

.bg-glow-3 {
  background: radial-gradient(circle, var(--accent-blue) 0%, transparent 70%);
  top: 40%;
  left: 50%;
  width: 30vw;
  height: 30vw;
  animation-delay: -10s;
}

@keyframes glow-float {
  0% {
    transform: translate(0, 0) scale(1);
  }
  100% {
    transform: translate(5%, 5%) scale(1.1);
  }
}

/* App Layout */
.app-layout {
  display: flex;
  min-height: 100vh;
  position: relative;
  z-index: 1;
}

/* Sidebar Styling */
.sidebar {
  width: 280px;
  background: var(--bg-sidebar);
  backdrop-filter: blur(20px);
  border-right: 1px solid var(--border-glass);
  display: flex;
  flex-direction: column;
  padding: 2.5rem 1.5rem;
  position: fixed;
  height: 100vh;
  z-index: 10;
  transition: var(--transition-smooth);
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 3.5rem;
  padding: 0 0.5rem;
  cursor: pointer;
  user-select: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.sidebar-brand:hover {
  opacity: 0.85;
  transform: translateY(-1px);
}

.brand-icon {
  font-size: 1.75rem;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 2px 8px rgba(0, 242, 254, 0.4));
}

.brand-name {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.5px;
}

.brand-name .highlight {
  color: var(--accent-cyan);
  text-shadow: 0 0 10px rgba(0, 242, 254, 0.3);
}

.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  flex: 1;
}

.nav-item {
  background: transparent;
  border: none;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.25rem;
  border-radius: 12px;
  cursor: pointer;
  font-family: var(--font-main);
  font-size: 1rem;
  font-weight: 500;
  text-align: left;
  transition: var(--transition-smooth);
  position: relative;
  overflow: hidden;
}

.nav-item::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 4px;
  background: linear-gradient(to bottom, var(--accent-cyan), var(--accent-blue));
  transform: scaleY(0);
  transition: var(--transition-smooth);
}

.nav-icon {
  width: 20px;
  height: 20px;
  transition: var(--transition-smooth);
}

.nav-item:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.04);
}

.nav-item.active {
  color: var(--accent-cyan);
  background: rgba(0, 242, 254, 0.06);
  font-weight: 600;
}

.nav-item.active::before {
  transform: scaleY(1);
}

.nav-item.active .nav-icon {
  stroke: var(--accent-cyan);
  filter: drop-shadow(0 0 5px rgba(0, 242, 254, 0.5));
}

.sidebar-footer {
  margin-top: auto;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  text-align: center;
}

.copyright {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 500;
}

.copyright-sub {
  font-size: 0.7rem;
  color: rgba(255, 255, 255, 0.25);
  margin-top: 0.25rem;
  letter-spacing: 1px;
  text-transform: uppercase;
}

/* Content Wrapper */
.content-wrapper {
  margin-left: 280px;
  flex: 1;
  padding: 3rem;
  max-width: 1200px;
  width: calc(100% - 280px);
  min-height: 100vh;
}

/* Tab Sections */
.tab-section {
  display: none;
  animation: fadeIn 0.4s ease-out forwards;
}

.tab-section.active {
  display: block;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* General Headings */
.badge {
  display: inline-block;
  padding: 0.4rem 0.8rem;
  background: rgba(0, 242, 254, 0.1);
  border: 1px solid rgba(0, 242, 254, 0.2);
  color: var(--accent-cyan);
  border-radius: 99px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 1rem;
}

.section-header {
  margin-bottom: 2.5rem;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -1px;
  margin-bottom: 0.5rem;
  background: linear-gradient(135deg, var(--text-primary) 30%, var(--text-muted));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-desc {
  color: var(--text-muted);
  font-size: 1.05rem;
}

/* Glassmorphism Panel Common */
.glass-panel {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-glass);
  border-radius: 20px;
  padding: 2rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
  transition: var(--transition-smooth);
}

/* ==================== 1. HOME SECTION ==================== */
.hero-container {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 2.5rem;
  align-items: center;
  margin-bottom: 4rem;
}

.hero-title {
  font-size: 3rem;
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -1.5px;
  margin-bottom: 1.25rem;
}

.gradient-text {
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 0 30px rgba(0, 242, 254, 0.15);
}

.hero-desc {
  color: var(--text-muted);
  font-size: 1.15rem;
  line-height: 1.6;
}

/* Hero Visual Card */
.visual-card {
  background: rgba(10, 15, 30, 0.6);
  backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: 16px;
  padding: 1.5rem;
  position: relative;
  overflow: hidden;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.card-glow {
  position: absolute;
  width: 150px;
  height: 150px;
  background: var(--accent-blue);
  filter: blur(50px);
  opacity: 0.3;
  top: -20px;
  right: -20px;
  pointer-events: none;
}

.visual-header {
  display: flex;
  gap: 6px;
  margin-bottom: 1.25rem;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.dot.red { background: #ff5f56; }
.dot.yellow { background: #ffbd2e; }
.dot.green { background: #27c93f; }

.visual-content {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.7;
}

.code-line {
  color: #a6accd;
}

.code-line-indented {
  color: #a6accd;
  padding-left: 1.5rem;
}

.token-keyword { color: #c792ea; }
.token-var { color: #82aaff; }
.token-class { color: #decb6b; }
.token-method { color: #82aaff; }
.token-string { color: #c3e88d; }

/* Dashboard Grid */
.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}

.dashboard-card {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  border: 1px solid var(--border-glass);
  border-radius: 16px;
  padding: 1.1rem;
  display: flex;
  gap: 0.85rem;
  cursor: pointer;
  box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.15);
  transition: var(--transition-bounce);
}

.dashboard-card:hover {
  transform: translateY(-6px) scale(1.01);
  background: var(--bg-card-hover);
  border-color: rgba(255, 255, 255, 0.15);
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.3);
}

.card-icon {
  width: 38px;
  height: 38px;
  border-radius: 11px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  flex-shrink: 0;
  transition: var(--transition-smooth);
}

.card-icon svg {
  width: 20px;
  height: 20px;
  stroke: currentColor;
}

/* Tool Theme Colors */
.calc-color {
  background: linear-gradient(135deg, #ff758c 0%, #ff7eb3 100%);
  box-shadow: 0 4px 15px rgba(255, 117, 140, 0.3);
}

.base-color {
  background: linear-gradient(135deg, #84fab0 0%, #8fd3f4 100%);
  color: #0f172a;
  box-shadow: 0 4px 15px rgba(132, 250, 176, 0.3);
}

.area-color {
  background: linear-gradient(135deg, #a1c4fd 0%, #c2e9fb 100%);
  color: #0f172a;
  box-shadow: 0 4px 15px rgba(161, 196, 253, 0.3);
}

.length-color {
  background: linear-gradient(135deg, #cfd9df 0%, #e2ebf0 100%);
  color: #0f172a;
  box-shadow: 0 4px 15px rgba(207, 217, 223, 0.3);
}

.space-color {
  background: linear-gradient(135deg, #7028e4 0%, #e5b2ca 100%);
  box-shadow: 0 4px 15px rgba(112, 40, 228, 0.35);
}

.pdf-color {
  background: linear-gradient(135deg, #f857a6 0%, #ff5858 100%);
  box-shadow: 0 4px 15px rgba(255, 88, 88, 0.3);
}

.dashboard-card:hover .card-icon {
  transform: rotate(8deg) scale(1.1);
}

.card-details h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.3rem;
}

.card-details p {
  color: var(--text-muted);
  font-size: 0.8rem;
  line-height: 1.4;
  margin-bottom: 0.6rem;
}

.go-link {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent-cyan);
  letter-spacing: 0.5px;
  transition: var(--transition-smooth);
}

.dashboard-card:hover .go-link {
  text-shadow: 0 0 8px rgba(0, 242, 254, 0.5);
  margin-left: 4px;
}


/* ==================== 2. CALCULATOR ==================== */
.calculator-layout {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 2rem;
  align-items: start;
}

.calc-card {
  background: var(--bg-card);
  border: 1px solid var(--border-glass);
  border-radius: 24px;
  padding: 1.75rem;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(20px);
}

.calc-display {
  background: var(--bg-display);
  border-radius: 16px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  text-align: right;
  min-height: 110px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  border: 1px solid rgba(255, 255, 255, 0.03);
}

.calc-expr {
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.95rem;
  min-height: 1.5rem;
  word-wrap: break-word;
  word-break: break-all;
  overflow: hidden;
  margin-bottom: 0.5rem;
}

.calc-current {
  font-family: var(--font-mono);
  font-size: 2.25rem;
  font-weight: 700;
  overflow-x: auto;
  white-space: nowrap;
  scrollbar-width: none; /* Firefox */
}

.calc-current::-webkit-scrollbar {
  display: none; /* Chrome/Safari */
}

.calc-keypad {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.75rem;
}

.btn {
  border: none;
  outline: none;
  font-family: var(--font-main);
  font-size: 1.25rem;
  font-weight: 600;
  border-radius: 16px;
  height: 60px;
  cursor: pointer;
  transition: var(--transition-smooth);
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn-num {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
}

.btn-num:hover {
  background: rgba(255, 255, 255, 0.12);
}

.btn-num:active {
  transform: scale(0.95);
}

.btn-op {
  background: rgba(79, 172, 254, 0.15);
  color: #60a5fa;
  font-size: 1.5rem;
}

.btn-op:hover {
  background: rgba(79, 172, 254, 0.25);
}

.btn-action {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-muted);
}

.btn-action:hover {
  background: rgba(255, 255, 255, 0.15);
  color: var(--text-primary);
}

.btn-equals {
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  color: var(--text-dark);
  font-weight: 800;
  font-size: 1.5rem;
  box-shadow: 0 0 15px rgba(0, 242, 254, 0.3);
}

.btn-equals:hover {
  filter: brightness(1.1);
  box-shadow: 0 0 20px rgba(0, 242, 254, 0.5);
}

.btn-double {
  grid-column: span 2;
}

/* History Panel */
.history-panel {
  background: var(--bg-card);
  border: 1px solid var(--border-glass);
  border-radius: 24px;
  padding: 1.75rem;
  height: 550px;
  display: flex;
  flex-direction: column;
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.panel-header h3 {
  font-size: 1.1rem;
  font-weight: 700;
}

.btn-clear-history {
  background: transparent;
  border: none;
  color: var(--accent-coral);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  padding: 0.25rem 0.5rem;
  border-radius: 6px;
  transition: var(--transition-smooth);
}

.btn-clear-history:hover {
  background: rgba(255, 117, 140, 0.1);
}

.history-list {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding-right: 0.25rem;
}

.history-list::-webkit-scrollbar {
  width: 6px;
}

.history-list::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
}

.empty-history {
  color: var(--text-muted);
  font-size: 0.9rem;
  text-align: center;
  margin: auto;
}

.history-item {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid rgba(255, 255, 255, 0.03);
  border-radius: 12px;
  padding: 0.75rem 1rem;
  text-align: right;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.history-item:hover {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.1);
}

.hist-expr {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.hist-result {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent-cyan);
}


/* ==================== 3. BASE CONVERTER ==================== */
.base-layout {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.base-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.input-card {
  background: var(--bg-card);
  border: 1px solid var(--border-glass);
  border-radius: 18px;
  padding: 1.5rem;
  box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.15);
  transition: var(--transition-smooth);
}

.input-card.focus-glow {
  border-color: var(--accent-cyan);
  box-shadow: 0 0 20px rgba(0, 242, 254, 0.15);
}

.input-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.input-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
}

.btn-copy {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.05);
  color: var(--text-muted);
  padding: 0.25rem 0.75rem;
  border-radius: 8px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  font-family: var(--font-main);
  transition: var(--transition-smooth);
}

.btn-copy:hover {
  background: rgba(0, 242, 254, 0.1);
  color: var(--accent-cyan);
  border-color: rgba(0, 242, 254, 0.2);
}

.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.base-input {
  width: 100%;
  background: var(--bg-display);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: 12px;
  padding: 0.85rem 4.5rem 0.85rem 1rem;
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-size: 1.2rem;
  outline: none;
  transition: var(--transition-smooth);
}

.base-input:focus {
  border-color: var(--accent-cyan);
}

.input-prefix {
  position: absolute;
  right: 12px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 6px;
  padding: 0.2rem 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  pointer-events: none;
}

.error-msg {
  display: none;
  font-size: 0.8rem;
  color: var(--accent-coral);
  margin-top: 0.5rem;
  font-weight: 500;
}

.input-card.invalid {
  border-color: var(--accent-coral);
  box-shadow: 0 0 15px rgba(255, 117, 140, 0.1);
}

.input-card.invalid .error-msg {
  display: block;
}

.info-card {
  padding: 1.5rem 2rem;
}

.info-card h4 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--accent-cyan);
}

.info-card ul {
  list-style: none;
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.info-card ul li::before {
  content: '⚡';
  margin-right: 0.5rem;
  font-size: 0.8rem;
}


/* ==================== 4. AREA CONVERTER ==================== */
.area-layout {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.conversion-panel {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.conv-row {
  display: grid;
  grid-template-columns: 1fr 50px 1fr;
  align-items: center;
  gap: 1.5rem;
}

.conv-field {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.conv-field label {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-muted);
}

.input-group {
  position: relative;
  display: flex;
  align-items: center;
}

.input-group input {
  width: 100%;
  background: var(--bg-display);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: 14px;
  padding: 1rem 3.5rem 1rem 1.25rem;
  color: var(--text-primary);
  font-family: var(--font-main);
  font-size: 1.35rem;
  font-weight: 600;
  outline: none;
  transition: var(--transition-smooth);
}

/* Chrome, Safari, Edge, Opera: Remove spin buttons */
.input-group input::-webkit-outer-spin-button,
.input-group input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* Firefox: Remove spin buttons */
.input-group input[type=number] {
  -moz-appearance: textfield;
}

.input-group input:focus {
  border-color: var(--accent-cyan);
  box-shadow: 0 0 15px rgba(0, 242, 254, 0.1);
}

.unit-tag {
  position: absolute;
  right: 1.25rem;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent-cyan);
}

.conv-arrow-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 1.75rem;
  color: var(--text-muted);
}

.conv-arrow-icon svg {
  stroke-width: 1.5;
  opacity: 0.7;
}

/* Shortcuts UI */
.shortcuts-wrapper {
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 1.5rem;
}

.shortcut-group {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.group-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-muted);
  letter-spacing: 0.5px;
}

.chip-container {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.chip {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.06);
  color: var(--text-muted);
  padding: 0.5rem 1rem;
  border-radius: 99px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  font-family: var(--font-main);
  transition: var(--transition-smooth);
}

.chip:hover {
  background: rgba(0, 242, 254, 0.1);
  border-color: rgba(0, 242, 254, 0.25);
  color: var(--accent-cyan);
  transform: translateY(-2px);
}

.chip:active {
  transform: translateY(0);
}


/* ==================== 5. LENGTH CONVERTER ==================== */
.length-layout {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.length-input-panel {
  padding: 1.5rem 2rem;
}

.length-input-panel .input-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

.length-val-field, .length-unit-field {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.length-val-field label, .length-unit-field label {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-muted);
}

.length-val-field input, .length-unit-field select {
  background: var(--bg-display);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: 12px;
  padding: 0.85rem 1.25rem;
  color: var(--text-primary);
  font-family: var(--font-main);
  font-size: 1.25rem;
  font-weight: 600;
  outline: none;
  transition: var(--transition-smooth);
}

.length-val-field input:focus, .length-unit-field select:focus {
  border-color: var(--accent-cyan);
}

/* Styled Select styling */
.length-unit-field select {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1.25rem center;
  background-size: 16px;
  padding-right: 3rem;
}

.length-unit-field select option {
  background: #0d1323;
  color: var(--text-primary);
}

/* Length Grid Output */
.length-grid-container {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

.length-result-card {
  background: var(--bg-card);
  border: 1px solid var(--border-glass);
  border-radius: 16px;
  padding: 1.25rem;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
  transition: var(--transition-smooth);
}

.length-result-card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(255, 255, 255, 0.12);
  transform: translateY(-2px);
}

.result-label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.result-val-wrap {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem;
}

.result-val {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  overflow-x: auto;
  white-space: nowrap;
  scrollbar-width: none;
  width: calc(100% - 35px);
}

.result-val::-webkit-scrollbar {
  display: none;
}

.result-unit {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent-cyan);
}

/* ==================== RESPONSIVE LAYOUT ==================== */
@media (max-width: 1024px) {
  .calculator-layout {
    grid-template-columns: 1fr;
  }

  .history-panel {
    height: 300px;
  }

  .length-grid-container {
    grid-template-columns: repeat(3, 1fr);
  }

  .dashboard-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .sidebar {
    width: 80px;
    padding: 2.5rem 0.75rem;
  }
  
  .sidebar-brand .brand-name, .sidebar-brand .brand-icon {
    display: none;
  }
  
  .brand-icon {
    display: block;
    margin: 0 auto;
  }
  
  .nav-item span {
    display: none;
  }
  
  .nav-item {
    justify-content: center;
    padding: 1rem 0;
  }
  
  .content-wrapper {
    margin-left: 80px;
    width: calc(100% - 80px);
    padding: 2rem;
  }
  
  .hero-container {
    grid-template-columns: 1fr;
  }
  
  .dashboard-grid {
    grid-template-columns: 1fr;
  }
  
  .base-grid {
    grid-template-columns: 1fr;
  }
  
  .conv-row {
    grid-template-columns: 1fr;
  }
  
  .conv-arrow-icon {
    transform: rotate(90deg);
    margin-top: 0;
    margin-bottom: 0.5rem;
  }
  
  .length-grid-container {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ==================== THEME SWITCHER UI ==================== */
.theme-switch-wrapper {
  margin-top: 1.5rem;
  padding: 0 0.5rem;
  margin-bottom: 1rem;
}

.theme-toggle-btn {
  width: 100%;
  background: rgba(15, 23, 42, 0.05);
  border: 1px solid var(--border-glass);
  color: var(--text-primary);
  padding: 0.75rem 1rem;
  border-radius: 12px;
  cursor: pointer;
  font-family: var(--font-main);
  font-weight: 600;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  transition: var(--transition-smooth);
}

.theme-toggle-btn:hover {
  background: rgba(15, 23, 42, 0.1);
  transform: translateY(-1px);
}

/* Light / Dark style specific details */
body.dark-theme .theme-toggle-btn {
  background: rgba(255, 255, 255, 0.05);
}

body.dark-theme .theme-toggle-btn:hover {
  background: rgba(255, 255, 255, 0.12);
}

@media (max-width: 768px) {
  .theme-switch-wrapper {
    padding: 0;
  }
  
  .theme-toggle-btn {
    padding: 0.75rem 0;
    border-radius: 50%;
    width: 44px;
    height: 44px;
    margin: 0 auto;
  }
  
  .theme-toggle-text {
    display: none;
  }
}


/* ==================== AdSense 광고 영역 ==================== */
.ad-container {
  margin: 2.5rem auto 0;
  max-width: 728px;
  width: 100%;
  min-height: 90px;
  text-align: center;
  overflow: hidden;
}

/* ==================== 우주 거리 탐색기 임베드 ==================== */
.space-embed-wrapper {
  width: 100%;
  border-radius: 20px;
  overflow: hidden;
  border: 1px solid rgba(124, 58, 237, 0.25);
  box-shadow: 0 10px 40px rgba(15, 23, 42, 0.18);
  background: #05060f;
}

.space-embed {
  display: block;
  width: 100%;
  height: calc(100vh - 220px);
  min-height: 640px;
  border: 0;
}

@media (max-width: 768px) {
  .space-embed {
    height: calc(100vh - 160px);
    min-height: 520px;
  }
}

/* ==================== PDF 워터마크 ==================== */
.pdf-layout {
  display: grid;
  grid-template-columns: 1.6fr 1fr;
  gap: 1.5rem;
  align-items: start;
}

.pdf-panel {
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.pdf-drop-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 2.25rem 1rem;
  border: 2px dashed var(--accent-cyan);
  border-radius: 16px;
  background: rgba(var(--accent-cyan-rgb), 0.06);
  cursor: pointer;
  text-align: center;
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.pdf-drop-zone:hover { background: rgba(var(--accent-cyan-rgb), 0.12); }
.pdf-drop-zone.dragging { background: rgba(var(--accent-cyan-rgb), 0.2); transform: scale(1.01); }
.pdf-drop-zone.has-file { border-style: solid; }

.pdf-drop-icon { font-size: 2.4rem; line-height: 1; }
.pdf-drop-text { font-size: 0.95rem; color: var(--text-muted); }
.pdf-drop-text span { color: var(--accent-cyan); font-weight: 700; text-decoration: underline; }
.pdf-file-name { font-size: 0.9rem; font-weight: 600; color: var(--text-primary); margin-top: 0.35rem; word-break: break-all; }

.pdf-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.1rem 1.25rem;
}

.pdf-field { display: flex; flex-direction: column; gap: 0.45rem; }
.pdf-field.full { grid-column: 1 / -1; }

.pdf-field label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.pdf-field .pdf-val { color: var(--accent-cyan); font-weight: 700; font-family: 'Space Mono', monospace; }

.pdf-field input[type="text"] {
  width: 100%;
  padding: 0.7rem 0.9rem;
  border-radius: 10px;
  border: 1px solid var(--border-glass);
  background: var(--bg-display);
  color: var(--text-primary);
  font-size: 1rem;
  font-family: inherit;
}

.pdf-field input[type="range"] { width: 100%; accent-color: var(--accent-cyan); }
.pdf-field input[type="color"] {
  width: 100%;
  height: 40px;
  padding: 2px;
  border: 1px solid var(--border-glass);
  border-radius: 10px;
  background: var(--bg-display);
  cursor: pointer;
}

.pdf-layout-toggle { display: flex; gap: 1.25rem; }
.pdf-layout-toggle label {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.pdf-layout-toggle input[type="radio"] { accent-color: var(--accent-cyan); }

.pdf-apply-btn {
  width: 100%;
  padding: 0.95rem;
  border: none;
  border-radius: 12px;
  font-size: 1.02rem;
  font-weight: 700;
  color: #fff;
  cursor: pointer;
  background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-purple) 100%);
  box-shadow: 0 6px 20px rgba(var(--accent-cyan-rgb), 0.25);
  transition: transform 0.15s ease, opacity 0.2s ease;
}
.pdf-apply-btn:hover:not(:disabled) { transform: translateY(-2px); }
.pdf-apply-btn:disabled { opacity: 0.5; cursor: not-allowed; }

.pdf-status { font-size: 0.9rem; font-weight: 600; min-height: 1.2em; text-align: center; }
.pdf-status.error { color: var(--accent-coral); }
.pdf-status.success { color: #16a34a; }
.pdf-status.loading { color: var(--accent-cyan); }

@media (max-width: 900px) {
  .pdf-layout { grid-template-columns: 1fr; }
  .pdf-options { grid-template-columns: 1fr; }
}