/* ============================================================
   Light to Sheet — Modern Dark UI
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* --- CSS Custom Properties --- */
:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: rgba(255, 255, 255, 0.03);
  --bg-card-hover: rgba(255, 255, 255, 0.06);
  --glass: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.08);
  --glass-border-hover: rgba(255, 255, 255, 0.15);
  --text-primary: #e8e8ed;
  --text-secondary: #8888a0;
  --text-muted: #55556a;
  --accent: #6c5ce7;
  --accent-light: #a29bfe;
  --accent-glow: rgba(108, 92, 231, 0.3);
  --accent-glow-strong: rgba(108, 92, 231, 0.5);
  --gradient-1: linear-gradient(135deg, #6c5ce7, #a29bfe);
  --gradient-2: linear-gradient(135deg, #6c5ce7, #fd79a8);
  --gradient-text: linear-gradient(135deg, #a29bfe, #fd79a8, #fdcb6e);
  --success: #00b894;
  --error: #ff6b6b;
  --error-bg: rgba(255, 107, 107, 0.08);
  --error-border: rgba(255, 107, 107, 0.2);
  --notice: #fdcb6e;
  --notice-bg: rgba(253, 203, 110, 0.06);
  --notice-border: rgba(253, 203, 110, 0.18);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 48px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 40px var(--accent-glow);
  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-spring: 0.6s cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* --- Animated Background --- */
.bg-effects {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}

.bg-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.15;
  animation: orbFloat 20s ease-in-out infinite;
}

.bg-orb--1 {
  width: 600px;
  height: 600px;
  background: var(--accent);
  top: -200px;
  left: -100px;
  animation-delay: 0s;
}

.bg-orb--2 {
  width: 500px;
  height: 500px;
  background: #fd79a8;
  bottom: -150px;
  right: -100px;
  animation-delay: -7s;
  animation-duration: 25s;
}

.bg-orb--3 {
  width: 400px;
  height: 400px;
  background: #fdcb6e;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  opacity: 0.08;
  animation-delay: -14s;
  animation-duration: 30s;
}

@keyframes orbFloat {
  0%, 100% { transform: translate(0, 0) scale(1); }
  25% { transform: translate(30px, -40px) scale(1.05); }
  50% { transform: translate(-20px, 20px) scale(0.95); }
  75% { transform: translate(40px, 30px) scale(1.02); }
}

/* Grid overlay */
.bg-grid {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse at center, black 30%, transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse at center, black 30%, transparent 70%);
}

/* --- Top Auth Navbar --- */
.auth-navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 0.75rem 1.5rem;
  pointer-events: none;
  animation: navbarSlideIn 0.6s var(--transition-smooth) both;
}

@keyframes navbarSlideIn {
  from { opacity: 0; transform: translateY(-20px); }
  to   { opacity: 1; transform: translateY(0); }
}

.auth-navbar-inner {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  pointer-events: auto;
}

/* Login button (Google branded) */
.login-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.5rem 1.1rem;
  font-family: 'Inter', sans-serif;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-primary);
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
}

.login-btn:hover {
  background: var(--bg-card-hover);
  border-color: var(--glass-border-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.login-btn .google-icon {
  flex-shrink: 0;
}

/* Navbar user profile (overrides the header version) */
.auth-navbar .user-profile {
  margin-top: 0;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

/* --- Container --- */
.container {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
  padding-top: 4rem; /* space for the fixed navbar */
}

/* --- Header --- */
header {
  text-align: center;
  margin-bottom: 3rem;
  padding-top: 1rem;
}

.logo-icon {
  display: inline-block;
  margin-bottom: 1.25rem;
  animation: logoEntrance 1s var(--transition-smooth) both;
}

.logo-icon svg {
  filter: drop-shadow(0 0 20px var(--accent-glow));
}

@keyframes logoEntrance {
  from {
    opacity: 0;
    transform: translateY(-20px) scale(0.8);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

h1 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: titleEntrance 0.8s var(--transition-smooth) 0.2s both;
  line-height: 1.2;
}

@keyframes titleEntrance {
  from {
    opacity: 0;
    transform: translateY(15px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.subtitle {
  color: var(--text-secondary);
  margin-top: 0.5rem;
  font-size: 1.05rem;
  font-weight: 400;
  animation: subtitleEntrance 0.8s var(--transition-smooth) 0.4s both;
}

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

/* --- Animated Piano SVG in header --- */
.piano-visual {
  margin-top: 1.5rem;
  display: flex;
  justify-content: center;
  animation: pianoEntrance 1s var(--transition-smooth) 0.5s both;
}

@keyframes pianoEntrance {
  from {
    opacity: 0;
    transform: translateY(10px) scaleX(0.9);
  }
  to {
    opacity: 1;
    transform: translateY(0) scaleX(1);
  }
}

.piano-key-white {
  fill: rgba(255, 255, 255, 0.08);
  stroke: rgba(255, 255, 255, 0.12);
  stroke-width: 0.5;
  transition: fill 0.3s ease, filter 0.3s ease;
}

.piano-key-black {
  fill: rgba(255, 255, 255, 0.02);
  stroke: rgba(255, 255, 255, 0.08);
  stroke-width: 0.5;
  transition: fill 0.3s ease, filter 0.3s ease;
}

.piano-key-white.active {
  fill: var(--accent);
  filter: drop-shadow(0 0 8px var(--accent-glow-strong));
}

.piano-key-black.active {
  fill: var(--accent-light);
  filter: drop-shadow(0 0 6px var(--accent-glow-strong));
}

/* --- Card (glass morphism wrapper) --- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  transition: border-color var(--transition-base), box-shadow var(--transition-base);
  animation: cardEntrance 0.6s var(--transition-smooth) 0.3s both;
}

.card:hover {
  border-color: var(--glass-border-hover);
}

@keyframes cardEntrance {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* --- Tabs --- */
.tabs {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 1.25rem;
  background: rgba(255, 255, 255, 0.03);
  border-radius: var(--radius-md);
  padding: 0.25rem;
  border: 1px solid rgba(255, 255, 255, 0.04);
}

.tab {
  flex: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1rem;
  font-family: 'Inter', sans-serif;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-muted);
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
}

.tab:hover {
  color: var(--text-secondary);
  background: rgba(255, 255, 255, 0.03);
}

.tab.active {
  color: var(--text-primary);
  background: rgba(108, 92, 231, 0.1);
  border-color: rgba(108, 92, 231, 0.2);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
  animation: fadeSlideIn 0.25s ease both;
}

/* --- File Upload --- */
.file-upload {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  padding: 2rem 1.5rem;
  background: rgba(255, 255, 255, 0.02);
  border: 2px dashed var(--glass-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  text-align: center;
}

.file-upload:hover {
  border-color: var(--accent);
  background: rgba(108, 92, 231, 0.04);
}

.file-upload.has-file {
  border-color: var(--success);
  background: rgba(0, 184, 148, 0.04);
}

.file-upload input[type="file"] {
  display: none;
}

.upload-icon {
  color: var(--accent-light);
  opacity: 0.6;
  transition: opacity var(--transition-base), transform var(--transition-base);
}

.file-upload:hover .upload-icon {
  opacity: 1;
  transform: translateY(-2px);
}

.upload-text {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.file-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* --- YouTube Note --- */
.youtube-note {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  margin-top: 0.75rem;
  padding: 0.65rem 0.85rem;
  font-size: 0.78rem;
  line-height: 1.5;
  color: var(--text-muted);
  background: rgba(253, 203, 110, 0.04);
  border: 1px solid rgba(253, 203, 110, 0.12);
  border-radius: var(--radius-sm);
}

.youtube-note svg {
  flex-shrink: 0;
  color: #fdcb6e;
  margin-top: 1px;
}

/* --- Input Label --- */
.input-label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
}

.input-label svg {
  color: var(--accent-light);
  flex-shrink: 0;
}

@keyframes fadeSlideIn {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* --- URL Input --- */
input[type="url"] {
  width: 100%;
  padding: 0.85rem 1rem;
  font-family: 'Inter', sans-serif;
  font-size: 0.95rem;
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  outline: none;
  transition: border-color var(--transition-base), box-shadow var(--transition-base), background var(--transition-base);
}

input[type="url"]::placeholder {
  color: var(--text-muted);
}

input[type="url"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow), inset 0 0 0 1px var(--accent);
  background: rgba(108, 92, 231, 0.04);
}

/* --- Submit Button --- */
#submit-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  margin-top: 1.25rem;
  padding: 0.85rem;
  font-family: 'Inter', sans-serif;
  font-size: 1rem;
  font-weight: 600;
  color: #fff;
  background: var(--gradient-1);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: transform var(--transition-fast), box-shadow var(--transition-base), opacity var(--transition-base);
}

#submit-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 40%, rgba(255, 255, 255, 0.15) 50%, transparent 60%);
  transform: translateX(-100%);
  transition: transform 0.6s ease;
}

#submit-btn:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: var(--shadow-glow);
}

#submit-btn:hover:not(:disabled)::before {
  transform: translateX(100%);
}

#submit-btn:active:not(:disabled) {
  transform: translateY(0) scale(0.99);
}

#submit-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-icon {
  display: flex;
  transition: transform var(--transition-base);
}

#submit-btn:hover:not(:disabled) .btn-icon {
  transform: translateX(2px);
}

/* --- Loading State --- */
#loading {
  text-align: center;
  padding: 3rem 1rem;
  animation: fadeIn 0.4s ease;
}

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

.loading-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
}

/* Waveform loader */
.waveform-loader {
  display: flex;
  align-items: center;
  gap: 4px;
  height: 40px;
}

.waveform-bar {
  width: 4px;
  border-radius: 2px;
  background: var(--gradient-1);
  animation: waveform 1.2s ease-in-out infinite;
}

.waveform-bar:nth-child(1) { height: 20px; animation-delay: 0s; }
.waveform-bar:nth-child(2) { height: 30px; animation-delay: 0.1s; }
.waveform-bar:nth-child(3) { height: 40px; animation-delay: 0.2s; }
.waveform-bar:nth-child(4) { height: 25px; animation-delay: 0.3s; }
.waveform-bar:nth-child(5) { height: 35px; animation-delay: 0.4s; }
.waveform-bar:nth-child(6) { height: 20px; animation-delay: 0.5s; }
.waveform-bar:nth-child(7) { height: 30px; animation-delay: 0.6s; }

@keyframes waveform {
  0%, 100% { transform: scaleY(0.4); opacity: 0.5; }
  50% { transform: scaleY(1); opacity: 1; }
}

.loading-text {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.loading-text span {
  display: inline-block;
  animation: loadingDots 1.4s infinite;
}

.loading-text span:nth-child(2) { animation-delay: 0.2s; }
.loading-text span:nth-child(3) { animation-delay: 0.4s; }

@keyframes loadingDots {
  0%, 80%, 100% { opacity: 0.3; }
  40% { opacity: 1; }
}

/* Animated progress ring */
.progress-ring {
  animation: ringPulse 2s ease-in-out infinite;
}

@keyframes ringPulse {
  0%, 100% { opacity: 0.3; }
  50% { opacity: 0.8; }
}

/* --- Error / Notice --- */
#error {
  position: relative;
  margin-top: 1rem;
  padding: 1.25rem 1.5rem;
  padding-right: 2.75rem;
  border-radius: var(--radius-md);
  display: flex;
  align-items: flex-start;
  gap: 0.85rem;
  animation: fadeSlideIn 0.35s ease both;
}

/* Variant: red error */
#error.error--danger {
  background: var(--error-bg);
  border: 1px solid var(--error-border);
  color: var(--error);
}
#error.error--danger .error-icon { color: var(--error); }
#error.error--danger .error-title { color: var(--error); }
#error.error--danger .error-detail { color: rgba(255, 107, 107, 0.8); }
#error.error--danger .error-suggestion { color: var(--text-secondary); }

/* Variant: amber notice */
#error.error--notice {
  background: var(--notice-bg);
  border: 1px solid var(--notice-border);
  color: var(--notice);
}
#error.error--notice .error-icon { color: var(--notice); }
#error.error--notice .error-title { color: var(--notice); }
#error.error--notice .error-detail { color: rgba(253, 203, 110, 0.75); }
#error.error--notice .error-suggestion { color: var(--text-secondary); }

.error-icon {
  flex-shrink: 0;
  margin-top: 1px;
}

.error-body {
  flex: 1;
  min-width: 0;
}

.error-title {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.2rem;
}

.error-detail {
  font-size: 0.85rem;
  line-height: 1.5;
}

.error-suggestion {
  font-size: 0.8rem;
  margin-top: 0.5rem;
  font-style: italic;
  line-height: 1.5;
}

.error-dismiss {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  background: none;
  border: none;
  color: inherit;
  opacity: 0.4;
  cursor: pointer;
  padding: 0.25rem;
  border-radius: 4px;
  transition: opacity var(--transition-fast);
  line-height: 0;
}
.error-dismiss:hover {
  opacity: 1;
}

/* --- Results Section --- */
#results {
  margin-top: 2.5rem;
}

.results-enter {
  animation: resultsEntrance 0.6s var(--transition-smooth) both;
}

@keyframes resultsEntrance {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Section headers */
.section-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
  margin-top: 2rem;
}

.section-header:first-child {
  margin-top: 0;
}

.section-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: rgba(108, 92, 231, 0.1);
  color: var(--accent-light);
  flex-shrink: 0;
}

.section-header h2 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* --- Sheet Music --- */
.sheet-music-wrapper {
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  overflow-x: auto;
  margin-bottom: 2rem;
  position: relative;
}

.sheet-music-wrapper::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--gradient-1);
  border-radius: var(--radius-md) var(--radius-md) 0 0;
  opacity: 0.5;
}

#sheet-music {
  font-family: 'JetBrains Mono', 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 0.78rem;
  line-height: 1.5;
  white-space: pre;
  margin: 0;
  color: var(--text-primary);
  letter-spacing: 0.01em;
}

/* Scrollbar styling for sheet music */
.sheet-music-wrapper::-webkit-scrollbar {
  height: 6px;
}

.sheet-music-wrapper::-webkit-scrollbar-track {
  background: transparent;
}

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

.sheet-music-wrapper::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* --- Download Buttons --- */
.downloads {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.download-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.25rem;
  font-family: 'Inter', sans-serif;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-primary);
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: all var(--transition-base);
  cursor: pointer;
}

.download-btn:hover {
  background: var(--bg-card-hover);
  border-color: var(--glass-border-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.download-btn svg {
  color: var(--accent-light);
  flex-shrink: 0;
}

/* --- Frame Preview --- */
#frame-preview {
  margin-bottom: 2rem;
  animation: fadeSlideIn 0.5s ease both;
}

.preview-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 0.75rem;
}

.preview-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 1.1rem;
  font-family: 'Inter', sans-serif;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-primary);
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  min-width: 90px;
  justify-content: center;
  transition: all var(--transition-base);
}

.preview-btn:hover:not(:disabled) {
  background: var(--bg-card-hover);
  border-color: var(--glass-border-hover);
  transform: translateY(-1px);
}

.preview-btn:disabled {
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.02);
  border-color: rgba(255, 255, 255, 0.04);
  cursor: not-allowed;
}

#frame-counter {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  color: var(--text-secondary);
  min-width: 180px;
  text-align: center;
}

.preview-image-wrapper {
  background: #000;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  position: relative;
}

#preview-img {
  width: 100%;
  display: block;
  transition: opacity 0.2s ease;
}

/* --- User Profile (Auth) --- */
.user-profile {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  margin-top: 1rem;
  padding: 0.5rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  animation: fadeSlideIn 0.3s ease both;
}

.user-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 1.5px solid var(--glass-border-hover);
  object-fit: cover;
}

.user-name {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  max-width: 200px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.sign-out-btn {
  padding: 0.3rem 0.75rem;
  font-family: 'Inter', sans-serif;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-muted);
  background: transparent;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.sign-out-btn:hover {
  color: var(--text-primary);
  border-color: var(--glass-border-hover);
}

/* --- Footer --- */
.footer {
  text-align: center;
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  color: var(--text-muted);
  font-size: 0.8rem;
  animation: fadeIn 1s ease 0.8s both;
}

.footer a {
  color: var(--accent-light);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer a:hover {
  color: var(--text-primary);
}

/* --- Utility --- */
.hidden {
  display: none !important;
}

/* --- Responsive --- */
@media (max-width: 640px) {
  .container {
    padding: 1.5rem 1rem 3rem;
    padding-top: 3.5rem;
  }

  h1 {
    font-size: 2rem;
  }

  .card {
    padding: 1.25rem;
  }

  .downloads {
    flex-direction: column;
  }

  .download-btn {
    justify-content: center;
  }

  .preview-controls {
    gap: 0.5rem;
  }

  #frame-counter {
    min-width: auto;
    font-size: 0.75rem;
  }

  .auth-navbar {
    padding: 0.5rem 1rem;
  }

  .login-btn {
    font-size: 0.8rem;
    padding: 0.45rem 0.9rem;
  }

  .user-profile {
    gap: 0.5rem;
    padding: 0.4rem 0.75rem;
  }

  .user-name {
    max-width: 120px;
    font-size: 0.8rem;
  }
}

/* --- Smooth Section Transitions --- */
.section-reveal {
  opacity: 0;
  transform: translateY(15px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.section-reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger children */
.stagger > * {
  opacity: 0;
  transform: translateY(10px);
  animation: staggerIn 0.4s ease forwards;
}

.stagger > *:nth-child(1) { animation-delay: 0.05s; }
.stagger > *:nth-child(2) { animation-delay: 0.1s; }
.stagger > *:nth-child(3) { animation-delay: 0.15s; }

@keyframes staggerIn {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* --- Focus visible (accessibility) --- */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* --- Selection --- */
::selection {
  background: var(--accent);
  color: #fff;
}