/* --- CIPHER CONSOLE THEME --- */

:root {
  /* Dark Mode Tokens (Default) */
  --bg-color: #0B0F14;
  --surface-color: #121821;
  --elevated-color: #1B2330;
  --border-color: #28323F;
  --text-primary: #E7ECF2;
  --text-secondary: #9AA7B5;
  
  /* Accents */
  --accent-amber: #E3A23C;
  --accent-violet: #9C7CF4;
  --accent-cyan: #3CC8E3;
  --accent-pink: #F47C9C;
  --accent-blue: #3C82E3;
  --accent-green: #4ADE80;
  --accent-coral: #F87171;
  --accent-teal: #2DD4BF;
  --accent-orange: #F97316;
  --accent-gray: #A1A1AA;
  
  /* Typography */
  --font-heading: 'IBM Plex Sans', sans-serif;
  --font-body: 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  
  /* Shapes */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-pill: 9999px;
  --border-thin: 1px solid var(--border-color);
  
  /* Transitions */
  --trans-fast: 0.15s ease;
}

body.theme-light {
  --bg-color: #FAF7F0;
  --surface-color: #FFFFFF;
  --elevated-color: #F1EFE8;
  --border-color: #E2DFD8;
  --text-primary: #1B2330;
  --text-secondary: #5C6B7D;
}

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

body {
  background-color: var(--bg-color);
  background-image: url('assets/DARK_THEME.png');
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.6;
  transition: background-color var(--trans-fast), color var(--trans-fast), background-image var(--trans-fast);
  overflow-x: hidden;
  animation: pageFadeIn 0.3s ease-out forwards;
}

@keyframes pageFadeIn {
  from { opacity: 0; transform: translateY(5px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Hide Scrollbar completely as requested */
::-webkit-scrollbar {
  display: none;
}

html {
  -ms-overflow-style: none;
  scrollbar-width: none;
}

html.theme-light-init body,
body.theme-light {
  --bg-color: #FAF7F0;
  --surface-color: #FFFFFF;
  --elevated-color: #F1EFE8;
  --border-color: #E2DFD8;
  --text-primary: #1B2330;
  --text-secondary: #5C6B7D;
  background-image: url('assets/LIGHT_THEME.png');
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.2;
}

a {
  color: inherit;
  text-decoration: none;
}

/* --- HEADER --- */
.console-header {
  position: sticky;
  top: 0;
  background-color: var(--surface-color);
  border-bottom: var(--border-thin);
  height: 60px;
  display: flex;
  align-items: center;
  padding: 0 2rem;
  z-index: 1000;
}

/* Faint Scrolling Ciphertext Drift */
.header-bg-animation {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--text-primary);
  opacity: 0.03;
  white-space: nowrap;
  pointer-events: none;
  animation: drift 60s linear infinite;
  content: "01A F9 2E C4 B8 7D 31 9A 5F E2 4C 8B 1D 6A 03 F8 27 E9 C1 B5 4D ...";
}
body.theme-light .header-bg-animation { opacity: 0.05; }

@keyframes drift {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

.header-content {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  width: 100%;
}

.logo {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--accent-cyan);
  justify-self: start;
}

.top-nav {
  display: flex;
  gap: 2rem;
  justify-self: center;
}

.top-nav a {
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), color 0.2s, text-shadow 0.2s;
  position: relative;
  padding-bottom: 0.25rem;
}

.top-nav a::after {
  content: '';
  position: absolute;
  width: 0;
  height: 2px;
  bottom: 0;
  left: 0;
  background-color: var(--accent-cyan);
  transition: width var(--trans-med) ease;
}

.top-nav a:hover,
.top-nav a.active {
  color: var(--text-primary);
  transform: translateY(-2px) scale(1.05);
  text-shadow: 0 4px 8px rgba(60, 200, 227, 0.4);
}

.top-nav a:hover::after,
.top-nav a.active::after {
  width: 100%;
}

.header-actions {
  display: flex;
  gap: 1rem;
  align-items: center;
  justify-self: end;
}

.search-container {
  display: flex;
  align-items: center;
  position: relative;
  background-color: var(--surface-color);
  border: var(--border-thin);
  border-radius: var(--radius-md);
  padding: 0.3rem 0.8rem;
  transition: border-color var(--trans-fast);
}

.search-container:focus-within {
  border-color: var(--accent-cyan);
}

#inline-search {
  background: none;
  border: none;
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.9rem;
  outline: none;
  width: 250px;
  padding: 0.2rem;
}

#inline-search-results {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background-color: var(--surface-color);
  border: var(--border-thin);
  border-radius: var(--radius-sm);
  list-style: none;
  margin-top: 0.5rem;
  z-index: 1000;
  max-height: 300px;
  overflow-y: auto;
}

#inline-search-results li a {
  display: block;
  padding: 0.5rem 1rem;
  color: var(--text-primary);
  border-bottom: var(--border-thin);
}

#inline-search-results li a:hover {
  background-color: var(--elevated-color);
}

.hidden {
  display: none !important;
}

button {
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1), color var(--trans-fast);
  display: inline-block;
}

button:hover {
  color: var(--text-primary);
  transform: translateY(-2px);
}

button:active {
  transform: translateY(1px);
}

.action-btn {
  background-color: var(--elevated-color);
  color: var(--text-primary);
  border: var(--border-thin);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.2s ease, background-color var(--trans-fast);
  box-shadow: 0 4px 0 rgba(0,0,0,0.3);
  display: inline-block;
}
.action-btn:hover {
  background-color: var(--border-color);
  transform: translateY(-2px) scale(1.02);
  box-shadow: 0 6px 12px rgba(60, 200, 227, 0.2), 0 4px 0 rgba(0,0,0,0.3);
}
.action-btn:active {
  transform: translateY(2px) scale(0.98);
  box-shadow: 0 0 0 rgba(0,0,0,0.3);
}
.action-btn.encrypt-btn {
  background-color: var(--accent-green);
  color: #000;
  border-color: var(--accent-green);
}
.action-btn.decrypt-btn {
  background-color: var(--accent-coral);
  color: #000;
  border-color: var(--accent-coral);
}

/* --- MAIN CONTENT & LAYOUT --- */
.main-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
  min-height: calc(100vh - 120px);
}

/* --- HOME & LIBRARY GRIDS --- */
.hero {
  text-align: center;
  margin: 4rem 0;
  position: relative;
  z-index: 10;
  pointer-events: none; /* Let clicks pass through empty space to 3D canvas */
}
.hero h1, .hero p, .hero-cta { 
  pointer-events: auto; /* Keep text and buttons clickable */
}
.hero h1 { font-size: 3rem; margin-bottom: 1rem; }
.hero p { font-size: 1.25rem; color: var(--text-secondary); margin-bottom: 2rem; }
.hero-cta { display: flex; gap: 1rem; justify-content: center; }

.cipher-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.cipher-card {
  background-color: var(--surface-color);
  border: var(--border-thin);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  transition: transform var(--trans-fast), border-color var(--trans-fast);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.cipher-card:hover {
  transform: translateY(-2px);
  border-color: var(--text-secondary);
}

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

.badge {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-pill);
  background-color: var(--elevated-color);
  border: var(--border-thin);
}

/* Category Colors */
.classical-substitution h3 { color: var(--accent-amber); }
.classical-transposition h3 { color: var(--accent-violet); }
.polygraphic-ciphers h3 { color: var(--accent-pink); }
.block-ciphers-symmetric-key- h3 { color: var(--accent-cyan); }
.stream-ciphers h3 { color: var(--accent-blue); }
.public-key-cryptosystems h3 { color: var(--accent-green); }
.authenticated-encryption-modes h3 { color: var(--accent-teal); }
.hash-password-functions h3 { color: var(--accent-orange); }
.hybrid-real-world-crypto h3 { color: var(--accent-gray); }

/* --- CIPHER PAGE --- */
.cipher-page {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.breadcrumbs {
  font-size: 0.9rem;
  color: var(--text-secondary);
}
.breadcrumbs a:hover { text-decoration: underline; }
.category-tag { font-family: var(--font-mono); }

.cipher-header h1 { font-size: 2.5rem; margin-bottom: 0.5rem; }
.cipher-header .tagline { font-size: 1.1rem; color: var(--text-secondary); }

.cipher-intro h2 { font-size: 1.5rem; margin-bottom: 1rem; border-bottom: var(--border-thin); padding-bottom: 0.5rem; }
.how-to-steps {
  list-style-position: inside;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.how-to-steps li { line-height: 1.5; }

/* Workspace */
.workspace-tabs {
  display: flex;
  gap: 0.5rem;
  border-bottom: var(--border-thin);
  margin-bottom: 1.5rem;
}

.tab-btn {
  padding: 0.75rem 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--text-secondary);
  border: var(--border-thin);
  border-bottom: none;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  background-color: var(--surface-color);
  cursor: pointer;
  margin-bottom: -1px;
}
.tab-btn.active {
  background-color: var(--elevated-color);
  color: var(--text-primary);
  border-bottom: 1px solid var(--elevated-color);
}

.panel {
  display: none;
  background-color: var(--elevated-color);
  border: var(--border-thin);
  border-radius: var(--radius-md);
  padding: 2rem;
  animation: fadeIn 0.2s ease;
}
.panel.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(5px); }
  to { opacity: 1; transform: translateY(0); }
}

.input-group {
  margin-bottom: 1.5rem;
}
.output-group {
  margin-top: 2.5rem; /* Space between encrypt button and ciphertext title */
  margin-bottom: 1.5rem;
}
.group-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}
.group-header label {
  margin-bottom: 0;
}
.util-actions {
  display: flex;
  gap: 0.5rem;
}
.util-btn {
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  background-color: transparent;
  border: var(--border-thin);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1), background-color 0.2s, color 0.2s, border-color 0.2s;
  cursor: pointer;
}
.util-btn:hover {
  background-color: color-mix(in srgb, var(--elevated-color) 80%, var(--accent-cyan) 20%);
  color: var(--text-primary);
  border-color: var(--accent-cyan);
  transform: translateY(-1px);
}
.util-btn:active {
  transform: translateY(1px);
}
label {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}
textarea, input[type="text"], input[type="number"] {
  width: 100%;
  background-color: var(--bg-color);
  color: var(--text-primary);
  border: var(--border-thin);
  border-radius: var(--radius-sm);
  padding: 0.75rem;
  font-family: var(--font-mono);
  font-size: 1rem;
  resize: vertical;
}
textarea { min-height: 100px; }

.output-box {
  width: 100%;
  min-height: 100px;
  background-color: var(--bg-color);
  color: var(--accent-green);
  border: var(--border-thin);
  border-radius: var(--radius-sm);
  padding: 0.75rem;
  font-family: var(--font-mono);
  font-size: 1rem;
  white-space: pre-wrap;
  word-break: break-all;
}

/* 3D Canvas */
.canvas-container {
  width: 100%;
  height: 400px;
  background-color: #000;
  border: var(--border-thin);
  border-radius: var(--radius-sm);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
.visualize-controls {
  margin-top: 1rem;
  display: flex;
  gap: 1rem;
  justify-content: center;
}

/* --- LEARNING PATH --- */
.path-intro {
  max-width: 760px;
  margin-bottom: 2.5rem;
}
.path-intro p {
  color: var(--text-secondary);
  margin-top: 0.75rem;
}
.path-stage {
  margin-bottom: 3rem;
}
.stage-heading {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.5rem;
}
.stage-num {
  flex-shrink: 0;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  border: var(--border-thin);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 1.1rem;
  color: var(--accent-cyan);
}
.stage-heading h2 {
  font-size: 1.5rem;
}
.stage-desc {
  color: var(--text-secondary);
  max-width: 700px;
  margin-bottom: 1.5rem;
}
.path-card .path-step {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
}
.path-why {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: var(--border-thin);
  max-width: 760px;
}
.path-why h2 {
  font-size: 1.3rem;
  margin-bottom: 0.75rem;
}
.path-why p {
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
}

/* --- HOME 3D CIPHER STAGE --- */
.home-3d-stage {
  position: relative;
  width: 100vw;
  margin-left: calc(-50vw + 50%);
  height: 600px;
  background: transparent;
  border: none;
  cursor: grab;
  z-index: 1;
  pointer-events: auto; /* Crucial: overrides .hero pointer-events: none */
}
.home-3d-stage:active { cursor: grabbing; }
.home-3d-stage canvas {
  display: block;
  width: 100% !important;
  height: 100% !important;
}
.home-3d-labels-layer {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 3;
}
.home-3d-hint,
.home-3d-controls,
.home-3d-category-rail,
.home-3d-panel {
  position: absolute;
  z-index: 5;
}
.home-3d-hint {
  bottom: 0.75rem;
  left: 50%;
  transform: translateX(-50%);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-secondary);
  background-color: var(--elevated-color);
  border: var(--border-thin);
  border-radius: var(--radius-pill);
  padding: 0.3rem 0.8rem;
  pointer-events: none;
  opacity: 0.9;
  white-space: nowrap;
}
.home-3d-controls {
  top: 0.85rem;
  right: 0.85rem;
  display: flex;
  gap: 0.45rem;
}
.home-3d-controls button,
.home-3d-category-rail button,
.home-3d-label {
  border: var(--border-thin);
  background-color: color-mix(in srgb, var(--elevated-color) 88%, transparent);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  cursor: pointer;
  transition: color var(--trans-fast), border-color var(--trans-fast), background-color var(--trans-fast), transform var(--trans-fast), opacity var(--trans-fast);
}
.home-3d-controls button {
  border-radius: var(--radius-pill);
  padding: 0.35rem 0.65rem;
  font-size: 0.72rem;
}
.home-3d-controls button:hover,
.home-3d-controls button:focus-visible,
.home-3d-category-rail button:hover,
.home-3d-category-rail button:focus-visible,
.home-3d-category-rail button.active,
.home-3d-label.selected {
  color: var(--text-primary);
  border-color: var(--accent-cyan);
  background-color: color-mix(in srgb, var(--elevated-color) 76%, var(--accent-cyan) 24%);
  outline: none;
}
.home-3d-label {
  position: absolute;
  transform: translate(-50%, -50%);
  max-width: min(190px, 42vw);
  padding: 0.28rem 0.58rem;
  border-radius: var(--radius-pill);
  font-size: 0.72rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  opacity: 0.68;
  pointer-events: auto;
  box-shadow: 0 0 16px rgba(0, 0, 0, 0.18);
}
.home-3d-label:hover {
  transform: translate(-50%, -50%);
}
.home-3d-label.selected {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1.04);
}
.home-3d-category-rail {
  left: 0.85rem;
  top: 0.85rem;
  width: min(230px, 34%);
  max-height: calc(100% - 5.5rem);
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  overflow: auto;
  padding-right: 0.25rem;
}
.home-3d-category-rail button {
  width: 100%;
  text-align: left;
  border-radius: var(--radius-sm);
  padding: 0.42rem 0.55rem;
  font-size: 0.72rem;
  line-height: 1.2;
}
.home-3d-panel {
  top: 1rem;
  left: 50%;
  width: 280px;
  max-width: calc(100% - 2rem);
  background-color: color-mix(in srgb, var(--elevated-color) 94%, transparent);
  border: var(--border-thin);
  border-radius: var(--radius-md);
  padding: 1rem;
  opacity: 0;
  transform: translateX(-50%) translateY(-6px);
  pointer-events: none;
  transition: opacity var(--trans-fast), transform var(--trans-fast);
  box-shadow: 0 18px 55px rgba(0, 0, 0, 0.26);
  backdrop-filter: blur(10px);
}
.home-3d-panel.open {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
  pointer-events: auto;
}
.home-3d-panel h4 {
  font-size: 0.95rem;
  margin-bottom: 0.55rem;
  padding-right: 1.25rem;
}
.home-3d-panel ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}
.home-3d-panel a {
  font-size: 0.85rem;
  color: var(--text-secondary);
  border-bottom: var(--border-thin);
  padding-bottom: 0.3rem;
  display: block;
}
.home-3d-panel a:hover,
.home-3d-panel a:focus-visible {
  color: var(--text-primary);
  outline: none;
}
.home-3d-panel-close {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1;
  padding: 0.25rem;
}
.home-3d-panel-close:hover,
.home-3d-panel-close:focus-visible {
  color: var(--text-primary);
  outline: none;
}
@media (max-width: 760px) {
  .home-3d-stage {
    height: 560px;
    margin-top: 1rem;
  }
  .home-3d-controls {
    left: 0.75rem;
    right: auto;
    top: 0.75rem;
  }
  .home-3d-category-rail {
    left: 0.75rem;
    right: 0.75rem;
    top: auto;
    bottom: 3.1rem;
    width: auto;
    max-height: none;
    flex-direction: row;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 0 0 0.2rem;
  }
  .home-3d-category-rail button {
    width: auto;
    min-width: 135px;
    text-align: center;
  }
  .home-3d-label {
    font-size: 0.66rem;
    max-width: 140px;
  }
  .home-3d-panel {
    width: min(280px, calc(100% - 1.5rem));
  }
  .home-3d-hint {
    bottom: 0.65rem;
    max-width: calc(100% - 1.5rem);
    overflow: hidden;
    text-overflow: ellipsis;
    font-size: 0.7rem;
    padding: 0.35rem 0.7rem;
  }
}

.console-footer {
  text-align: center;
  padding: 2rem;
  border-top: var(--border-thin);
  color: var(--text-secondary);
  font-size: 0.85rem;
  display: flex;
  justify-content: center;
}

.console-footer p {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.console-footer a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--trans-fast);
}

.console-footer a:hover {
  color: var(--accent-cyan);
}

/* --- INTERACTIVE TOYS --- */
.interactive-toy-card {
  background-color: var(--elevated-color);
  border: var(--border-thin);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin-bottom: 2rem;
}
.toy-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  border-bottom: var(--border-thin);
  padding-bottom: 1rem;
}
.caesar-letter {
  box-sizing: border-box;
  width: 24px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--surface-color);
  border: var(--border-thin);
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  flex-shrink: 0;
}

/* --- CHALLENGE INPUT STATES --- */
.challenge-input.correct {
  border: 2px solid #22c55e !important;
  outline: 2px solid #22c55e !important;
  box-shadow: 0 0 10px rgba(34, 197, 94, 0.3);
}

.challenge-input.incorrect {
  border: 2px solid #ef4444 !important;
  outline: 2px solid #ef4444 !important;
  animation: shake 0.4s cubic-bezier(.36,.07,.19,.97) both;
}

@keyframes shake {
  10%, 90% { transform: translate3d(-2px, 0, 0); }
  20%, 80% { transform: translate3d(4px, 0, 0); }
  30%, 50%, 70% { transform: translate3d(-6px, 0, 0); }
  40%, 60% { transform: translate3d(6px, 0, 0); }
}

/* Scroll to Top Button */
#scroll-to-top-btn {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 3.5rem;
  height: 3.5rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
              visibility 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
              transform 0.2s cubic-bezier(0.4, 0, 0.2, 1), 
              box-shadow 0.2s ease;
  background: var(--bg-color);
  color: var(--accent-cyan);
  border: 2px solid var(--accent-cyan);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3), 0 0 10px rgba(0, 240, 255, 0.2);
  cursor: pointer;
  transform: translateY(20px);
}

#scroll-to-top-btn.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

#scroll-to-top-btn:hover {
  transform: translateY(-5px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4), 0 0 20px rgba(0, 240, 255, 0.4);
  background: var(--surface-color);
}