styles.css

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

strong {
    font-weight: normal;
}

/* ------------------------------
   1. Font Import & Variable Setup
------------------------------ */
@font-face {
  font-family: 'Euclid Circular B';
  src: url('fonts/EuclidCircularB.woff2') format('woff2');
  font-style: normal;
  font-display: swap;
}

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

:root {
  --font-display: 'Euclid Circular B', sans-serif;
  --font-body: 'Inter', sans-serif;
  --font-mono: 'IBM Plex Mono', monospace;

  --color-text-default: #161615;
  --color-text-secondary: #5d5d5d;
  /* Accent colors */
  --accent-yellow: #FFFF00;
  --accent-pink: #FF69B4;
}

/* ------------------------------
   2. Base Typography (h1 ~ p)
------------------------------ */
h1 {
  font-family: var(--font-display);
  font-size: 4rem;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--color-text-default);
  font-weight: 400;
}

h2 {
  font-family: var(--font-display);
  font-size: 2.5rem;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--color-text-default);
  font-weight: 400;
}

h3 {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 4vw, 2.3rem);
  line-height: 125%;
  letter-spacing: -0.035em;
  font-weight: 300;
}

h4 {
  font-family: var(--font-body);
  font-size: 1.5rem;
  line-height: 1.4;
  color: var(--color-text-default);
  font-weight: 400;
}

h5 {
  font-family: var(--font-body);
  font-size: 1.25rem;
  line-height: 1.5;
  color: var(--color-text-default);
  font-weight: 400;
}

h6 {
  font-family: var(--font-body);
  font-size: 1.125rem;
  line-height: 1.5;
  color: var(--color-text-default);
  font-weight: 400;
}

p {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text-secondary);
}

html {
  font-size: 16px;
  overflow-x: hidden;
  overflow-y: auto;
  max-width: 100%;
  scroll-behavior: smooth;
}

@media (max-width: 1280px) {
  html {
    font-size: 15px;
  }
}

@media (max-width: 768px) {
  html {
    font-size: 14px;
  }
}

:root {
  /* Dark Mode */
  --dark-mode: true;

  /* Primary */
  --supertone_blue: #227cff;
  --primary: var(--supertone_blue);
  --primary-dark: #0849CC;
  --primary-light: var(--supertone_blue);
  --accent: var(--supertone_blue);

  /* Secondary / Highlight */
  --highlight: #f4fa7d;

  /* Backgrounds */
  --light: #000000;
  --light-lighter: #1a1a1a;
  --light-darker: #2a2a2a;

  /* Text */
  --text: #ffffff;
  --text-secondary: #b0b0b0;
  --text-muted: #888888;

  /* Border */
  --border: #444444;

  /* Status / Semantic */
  --success: #3FB950;

  /* Gradients */
  --gradient: linear-gradient(135deg, var(--supertone_blue) 0%, var(--supertone_blue) 100%);
  --gradient-alt: linear-gradient(135deg, var(--supertone_blue) 0%, var(--supertone_blue) 100%);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--light);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
    max-width: 100%;
    position: relative;
    font-weight: 300;
}

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
}

@media (min-width: 1921px) {
  .container {
    max-width: none;
  }
  
  /* Scale elements by 1.75x for large screens */
  .demo-result-item.supertonic-result-item {
    --result-title-size: calc(1rem * 1.75);
  }
  
  .demo-result-item.supertonic-result-item .demo-result-title {
    font-size: calc(1rem * 1.75);
  }
  
  .demo-result-item.supertonic-result-item .demo-result-info .stat-value {
    font-size: calc(1rem * 1.75);
  }
  
  .demo-result-item.supertonic-result-item .demo-result-info .stat-label {
    font-size: calc(0.7rem * 1.75);
  }
  
  .demo-result-item.supertonic-result-item .demo-result-info .stat-value .stat-label.stat-suffix {
    font-size: calc(0.7rem * 1.75);
  }
  
  .demo-result-item.supertonic-result-item .custom-audio-player .time-display {
    font-size: calc(1rem * 1.75);
  }
  
  #play-pause-btn {
    width: calc(40px * 1.75) !important;
    height: calc(40px * 1.75) !important;
  }
  
  #play-pause-btn svg {
    width: calc(24px * 1.75) !important;
    height: calc(24px * 1.75) !important;
  }
  
  .demo-result-item {
    padding: calc(1rem * 1.75) calc(1.5rem * 1.75) !important;
  }
  
  .demo-download-btn svg {
    width: calc(16px * 1.75) !important;
    height: calc(16px * 1.75) !important;
  }
  
  .demo-result-item.supertonic-result-item .demo-result-info .stat-value .stat-prefix {
    left: calc(-2.3rem * 1.75);
  }
}

@media (max-width: 1280px) {
  .container {
    max-width: 100%;
    padding: 0 1.5rem;
  }
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.535rem;
    padding: 0.8rem 2.1rem;
    border-radius: 1rem;
    text-decoration: none;
    transition: all 0.3s ease;
    font-size: 1rem;
    cursor: pointer;
    border: 1px solid;
    font-family: inherit;
    line-height: 150%;
    background: var(--light);
}

.btn-primary {
    background: var(--gradient);
    color: white;
    border-color: transparent;
    box-shadow: 0 4px 20px rgba(57, 121, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 30px rgba(57, 121, 255, 0.5);
}

.btn-secondary {
    background: rgba(242, 242, 242, 0);
    color: var(--text);
    width: 11rem;
    display: flex;
    justify-content: center;
    align-items: center;
}

.btn-secondary:hover {
    border-color: var(--primary);
    background: var(--light);
    transform: translateY(-2px);
}

/* Text toggle style for btn-secondary buttons */
.btn.btn-secondary.text-toggle {
    background: none;
    border: none;
    padding: 0;
    display: inline;
    font-family: inherit;
    border-radius: 0;
    box-shadow: none;
    transform: none;
    gap: 0;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    width: auto;
    justify-content: initial;
    align-items: initial;
}

/* Preset item styles (matching speaker-item) */
.preset-item {
    font-size: 1rem;
    color: #999;
    cursor: pointer;
    transition: all 0.2s ease;
    padding: 0.25rem 0;
    white-space: nowrap;
}

.preset-item:hover {
    color: #ddd;
}

.preset-item.active {
    color: var(--text);
    opacity: 1;
    text-decoration: underline;
    text-decoration-style: solid;
    text-decoration-thickness: 1px;
    text-underline-offset: 4px;
}

.preset-icon {
    display: inline-flex;
    align-items: center;
    vertical-align: middle;
}

.preset-icon svg {
    display: block;
    fill: #ffffff !important;
}

.preset-icon svg rect {
    fill: #ffffff !important;
}

.btn.btn-secondary.text-toggle:hover {
    opacity: 0.7;
    border-color: transparent;
    background: transparent;
    transform: none;
}

.btn.btn-secondary.text-toggle.active {
    color: var(--supertone_blue);
    text-decoration: underline;
    text-decoration-style: wavy;
    text-decoration-thickness: 1px;
    text-decoration-color: var(--supertone_blue);
    text-underline-offset: 4px;
    border-color: transparent;
    background: transparent;
    font-weight: 400;
}

.btn.btn-secondary svg {
    color: var(--text-secondary);
}

#presetButtonGroup #presetBookBtn {
    display: none;
}

.stat {
    text-align: center;
    padding: 0 1.25rem 0 1.25rem;
    flex-shrink: 0;
    position: relative;
}

.stat-value {
    font-size: 8rem;
    color: var(--text);
    margin-bottom: 0;
    font-family: var(--font-display);
    line-height: 150%;
    letter-spacing: -0.04em;
}

.stat-label {
    font-size: 1rem;
    text-transform: none;
    letter-spacing: normal;
    line-height: 1.3125rem;
    font-family: var(--font-body);
    display: inline-flex;
    align-items: center;
}

.stat-arrow {
    margin-left: 0.25em;
    display: inline-block;
}

/* Interactive TTS Demo Section */
.interactive-demo {
    padding: 3.0rem 0 0.5rem 0;
}

.demo-container {
    margin: 0 auto;
    background: none;
    border-radius: 12px;
    padding: 2.5rem 4.5rem 0;
    box-shadow: none;
}

.demo-status-box {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.75rem;
    padding: 0.2rem 1rem;
    background: rgba(255, 152, 0, 0.1);
    border: 1px solid rgba(255, 152, 0, 0.3);
    border-radius: 8px;
    margin-bottom: 0rem;
    min-height: 45px;
    position: relative;
    overflow: hidden;
    --status-progress: 0%;
    --status-progress-color: rgba(255, 152, 0, 0.2);
    z-index: 0;
}

.demo-status-box::before {
    content: '';
    position: absolute;
    inset: 0;
    width: var(--status-progress, 0%);
    background: var(--status-progress-color);
    transition: width 0.4s ease;
    z-index: 0;
    pointer-events: none;
}

.demo-status-box > * {
    position: relative;
    z-index: 1;
}

.demo-status-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.demo-status-box.success {
    background: rgba(63, 185, 80, 0.1);
    border-color: rgba(63, 185, 80, 0.3);
    font-family: 'IBM Plex Mono', monospace;
    --status-progress-color: rgba(63, 185, 80, 0.2);
}

.demo-status-box.success .demo-status-text {
    color: var(--success);
}

.demo-status-box.success * {
    font-family: inherit;
}

.demo-status-text {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 0.85rem;
    font-weight: 400;
}

.demo-status-box.error {
    background: rgba(239, 68, 68, 0.1);
    border-color: rgba(239, 68, 68, 0.3);
    --status-progress-color: rgba(239, 68, 68, 0.2);
}

.demo-status-box.error .demo-status-text {
    color: #ef4444;
}

/* WASM Warning Banner - subtle persistent notification */
.wasm-warning-banner {
    padding: 0.5rem 1rem;
    background: rgba(239, 68, 68, 0.08);
    border: 1px solid rgba(239, 68, 68, 0.25);
    border-radius: 6px;
    font-family: var(--font-body);
    font-size: 0.8rem;
    color: #b91c1c;
    margin-top: 0.5rem;
    line-height: 1.4;
}

.demo-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
    margin-bottom: 2rem;
}

.demo-input-section,
.demo-output-section {
    display: flex;
    flex-direction: column;
    width: 100%;
    min-width: 0;
}

.demo-input-section {
    height: 100%;
    position: relative;
    overflow: visible;
}

.demo-input-label {
    display: none;
}

.demo-input-section label {
    display: block;
    color: var(--text);
    font-size: 1.125rem;
    margin: 0;
}

.demo-char-counter {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    font-size: 1rem;
    color: var(--text-muted);
    justify-content: flex-end;
}

.demo-char-counter.error,
.demo-char-counter.warning {
    color: var(--text-muted);
}

.demo-char-counter.valid {
    color: var(--text-muted);
}

.demo-char-warning {
    color: #ef4444;
    font-size: 1rem;
    transition: all 0.2s ease;
}

#demoCharCount {
    display: inline-block;
    min-width: 1.5ch;
    text-align: right;
    font-variant-numeric: tabular-nums;
}

.demo-char-counter.valid .demo-char-warning {
    display: none;
}

.demo-input-section textarea,
.demo-text-input-editable {
    width: 100%;
    padding: 0;
    background: none;
    border: none;
    border-radius: 0;
    position: relative;
    color: var(--text);
    font-size: 2rem;
    font-weight: 400;
    line-height: 1.2;
    font-family: inherit;
    resize: vertical;
    overflow-y: auto;
    transition: all 0.3s ease;
    margin-bottom: 0;
    min-height: 90px;
    height: 330px;
    max-height: none;
    flex: 0 0 auto;
    -webkit-text-decoration-skip-ink: none;
    text-decoration-skip-ink: none;
}

/* Hide spellcheck underlines */
.demo-text-input-editable::spelling-error,
#demoTextInput::spelling-error {
    text-decoration: none !important;
    background: none !important;
}

#demoTextInput {
    position: relative;
    overflow-y: auto;
    scrollbar-color: transparent transparent;
    scrollbar-width: thin;
    white-space: pre-wrap;
    word-wrap: break-word;
    transition: scrollbar-color 0.3s ease;
}

.demo-input-section::after {
    content: '';
    position: absolute;
    left: -27px;
    top: 0;
    width: 4px;
    height: var(--demo-text-input-height, 330px);
    min-height: 90px;
    background: var(--text);
    pointer-events: none;
    z-index: 10;
}

#demoTextInput.scrolling {
    scrollbar-color: var(--light) transparent;
}

#demoTextInput::-webkit-scrollbar {
    width: 10px;
}

#demoTextInput::-webkit-scrollbar-track {
    background: transparent !important;
    border: none;
}

#demoTextInput::-webkit-scrollbar-thumb {
    background: transparent !important;
    border-radius: 999px;
    transition: background 0.3s ease;
}

#demoTextInput.scrolling::-webkit-scrollbar-thumb {
    background: var(--light) !important;
}

#demoTextInput.scrolling::-webkit-scrollbar-thumb:hover {
    background: var(--light-darker) !important;
}

.demo-input-section textarea:focus,
.demo-text-input-editable:focus {
    outline: none;
    border-color: transparent;
    background: none;
}

.demo-input-section textarea::placeholder {
    color: var(--text-muted);
}

/* Placeholder for contenteditable */
.demo-text-input-editable:empty:before {
    content: attr(data-placeholder);
    color: var(--text-muted);
    pointer-events: none;
}

.demo-header-wrapper {
    position: relative;
    margin-bottom: 1rem;
}

.demo-header-icon {
    position: absolute;
    left: -27px;
    top: 57%;
    transform: translateY(-50%) scale(1.3);
    transform-origin: center;
    width: 20px;
    height: 20px;
}

.demo-header {
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.6;
    color: var(--text);
    margin: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    width: 100%;
}

.demo-header-text {
    flex: 1;
}

.demo-header-links {
    display: flex;
    align-items: center;
    gap: 15px;
    white-space: nowrap;
    flex-shrink: 0;
}

.demo-header-bold {
    font-weight: 600;
    color: var(--text);
}

.highlight-multilingual {
    color: var(--text);
}

.demo-header-link {
    color: #ffffff;
    text-decoration: underline;
    text-decoration-style: solid;
    text-decoration-thickness: 1px;
    text-underline-offset: 4px;
    transition: opacity 0.2s ease;
    text-decoration-skip-ink: none;
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
}

.demo-header-link:hover {
    opacity: 0.8;
}

.demo-header-link-icon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    display: inline-block;
    vertical-align: middle;
}


.demo-controls {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.demo-params-row {
    display: grid;
    grid-template-columns: 1fr 1fr 2fr;
    gap: 1rem;
    align-items: flex-start;
    margin: 1.5rem 0 1rem;
}

.demo-params-row .demo-param {
    display: flex;
    flex-direction: column;
}

.demo-params-row #demoGenerateBtn {
    align-self: flex-end;
    margin-top: 0;
    grid-column: 3;
}

.demo-param {
    display: flex;
    flex-direction: column;
}

.demo-param-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.35rem;
    gap: 1rem;
    font-weight: 400;
}

.demo-param label {
    font-size: 1rem;
    color: var(--text);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
}

.param-value {
    font-size: 1rem;
    color: var(--text);
}

.demo-params-row .param-value {
    font-weight: 400;
    color: #999;
}

.demo-param input[type="range"] {
    width: 100%;
    height: 18px;
    background: transparent;
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    cursor: pointer;
    margin: 0;
    padding: 0;
}

.demo-param input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 14px;
    height: 14px;
    background: #000;
    border: 1px solid #ffffff;
    border-radius: 50%;
    cursor: pointer;
    margin-top: -7px;
}

.demo-param input[type="range"]::-webkit-slider-thumb:hover {
    background: #000;
    border: 1px solid #ffffff;
}

.demo-param input[type="range"]::-moz-range-thumb {
    width: 14px;
    height: 14px;
    background: #000;
    border: 1px solid #ffffff;
    border-radius: 50%;
    cursor: pointer;
}

.demo-param input[type="range"]::-moz-range-thumb:hover {
    background: #000;
    border: 1px solid #ffffff;
}

.demo-param input[type="range"]::-webkit-slider-runnable-track {
    width: 100%;
    height: 1px;
    background: #999;
    border: none;
    border-radius: 0;
}

.demo-param input[type="range"]::-moz-range-track {
    width: 100%;
    height: 1px;
    background: #999;
    border: none;
    border-radius: 0;
}

/* Reusable text toggle style */
.text-toggle {
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    background: none;
    border: none;
    padding: 0;
    font-family: inherit;
    font-weight: 400;
}

.text-toggle:hover {
    opacity: 0.7;
}

.text-toggle.active {
    color: var(--supertone_blue);
    text-decoration: underline;
    text-decoration-style: wavy;
    text-decoration-thickness: 1px;
    text-decoration-color: var(--supertone_blue);
    text-underline-offset: 4px;
}

/* Speaker List Styles */
.speaker-container {
    display: flex;
    flex-wrap: nowrap;
    align-items: center;
    gap: 0.3rem;
}

.speaker-label {
    font-size: 1rem;
    color: var(--text);
    font-weight: 400;
    white-space: pre;
    flex-shrink: 0;
}

.speaker-list {
    display: flex;
    flex-wrap: nowrap;
    align-items: center;
    overflow-x: auto;
}

.speaker-item {
    font-size: 1rem;
    color: #999;
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.speaker-separator {
    color: #999;
    font-size: 1rem;
    pointer-events: none;
    white-space: pre;
}

.speaker-item:hover {
    color: #ddd;
}

.speaker-item.active {
    color: var(--text);
    opacity: 1;
    text-decoration: underline;
    text-decoration-style: solid;
    text-decoration-thickness: 1px;
    text-underline-offset: 4px;
}

.speaker-item.disabled {
    opacity: 0.4;
    cursor: not-allowed;
    pointer-events: none;
}

.auto-detect-text {
    font-size: 1rem;
    color: #999;
    padding: 0.25rem 0;
    white-space: nowrap;
    text-decoration: underline;
    text-decoration-style: solid;
    text-decoration-thickness: 1px;
    text-underline-offset: 4px;
}

.language-info {
    display: flex;
    flex-wrap: nowrap;
    align-items: center;
    gap: 0.3rem;
    margin-top: 0.25rem;
}

.language-info .speaker-label {
    margin-right: 0;
}

.speaker-item-create {
    color: #ffffff;
    opacity: 1;
}

.speaker-item-create:hover {
    opacity: 0.8;
    text-decoration: underline;
    text-decoration-style: solid;
    text-decoration-thickness: 1px;
    text-underline-offset: 4px;
}

/* Speaker Tooltip */
.speaker-tooltip {
    position: fixed;
    display: none;
    background: var(--text);
    color: var(--light);
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.875rem;
    line-height: 1.4;
    white-space: nowrap;
    z-index: 10000;
    pointer-events: none;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

/* Coming Soon Modal */
.coming-soon-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 10000;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.coming-soon-modal.show {
    display: flex;
    animation: modalFadeIn 0.2s ease-out;
}

.coming-soon-modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.coming-soon-modal-content {
    position: relative;
    background: white;
    border-radius: 0.75rem;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    max-width: 400px;
    width: 100%;
    overflow: hidden;
    animation: modalSlideUp 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.coming-soon-modal-header {
    padding: 1.5rem 1.5rem 1rem;
    text-align: center;
    border-bottom: 1px solid var(--light-darker);
}

.coming-soon-modal-header h3 {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--text);
    margin: 0;
}

.coming-soon-modal-body {
    padding: 1.5rem;
    text-align: center;
}

.coming-soon-modal-body p {
    font-family: var(--font-body);
    font-size: 1rem;
    color: var(--text-secondary);
    margin: 0;
    line-height: 1.6;
}

.coming-soon-modal-footer {
    padding: 1rem 1.5rem 1.5rem;
    display: flex;
    justify-content: center;
}

.coming-soon-modal-btn {
    padding: 0.75rem 2rem;
    border-radius: 0.5rem;
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    outline: none;
    background: var(--supertone_blue);
    color: white;
}

.coming-soon-modal-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(34, 124, 255, 0.3);
}

.coming-soon-modal-btn:active {
    transform: translateY(0);
}

.demo-generate-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.875rem 1.5rem;
    border: 1px solid var(--accent-yellow);
    border-radius: 999px;
    background: none;
    font-size: 0.9375rem;
    font-family: inherit;
    cursor: pointer;
    margin-top: 1.5rem;
}

#demoGenerateBtn {
    color: var(--accent-yellow);
    font-weight: 400;
}

#demoGenerateBtn img {
    flex-shrink: 0;
    transform: scale(1.3);
    transform-origin: center;
    filter: brightness(0) invert(90%) sepia(100%) saturate(1000%) hue-rotate(0deg);
}

.demo-generate-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.demo-results {
    flex: 1;
    background: var(--light-lighter);
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    padding: 0;
    display: flex;
    flex-direction: column;
    width: 100%;
    min-width: 0;
    overflow-x: hidden;
    grid-column: 1 / -1;
    font-family: var(--font-mono);
    font-weight: 400;
}

#demoResults {
    display: none;
}

.demo-placeholder {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--text-muted);
}

.demo-placeholder-icon {
    font-size: 2.5rem;
    margin-bottom: 0.75rem;
    opacity: 0.5;
    animation: float 3s ease-in-out infinite;
}

.demo-placeholder.generating .demo-placeholder-icon {
    animation: spin 2s linear infinite;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-10px);
    }
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}

.demo-placeholder p {
    font-size: 1rem;
    color: var(--text-muted);
    margin: 0;
}

.demo-result-item {
    --result-progress: 0%;
    --result-title-size: 1rem;
    position: relative;
    overflow: hidden;
    z-index: 0;
    display: grid;
    grid-template-columns: 12% 40% auto;
    column-gap: 2rem;
    row-gap: 1rem;
    align-items: center;
    padding: 1rem 1.5rem;
    background: #000;
}

.demo-result-item.supertonic-result-item {
    background: #000;
}

body.comparison-mode .demo-result-item {
    grid-template-columns: 23% 31% auto;
}

#demoResults > .demo-result-item + .demo-result-item {
    border-top: 1px dashed #aaa;
}

.demo-result-item.supertonic-result-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: var(--result-progress, 0%);
    height: 100%;
    background: #1a1a1a;
    pointer-events: none;
    z-index: -1;
    transition: width 0.1s ease;
}

.demo-result-title {
    display: flex;
    flex-direction: column;
    gap: 0.1rem;
    font-size: var(--result-title-size, 1rem);
    line-height: 1.2;
    grid-column: 1;
    justify-content: center;
    font-weight: 400;
}

.demo-result-title span {
    font-weight: 400;
}

.demo-result-title .title-status {
    font-size: 0.85rem;
    color: var(--text-secondary);
    display: none;
}

.demo-result-title .title-status.status-success {
    color: var(--success);
}

.demo-result-title .title-status.status-error {
    color: #ef4444;
}

.demo-result-title .title-status.status-running {
    color: var(--accent);
}

.demo-result-title .title-sub {
    color: var(--text-secondary);
}

.demo-result-info {
    display: flex;
    flex-direction: row;
    align-items: center;
    justify-content: space-evenly;
    align-self: stretch;
    padding: 0;
    margin: 0;
    flex-wrap: wrap;
    grid-column: 2;
}

.demo-result-info .stat {
    text-align: center;
    padding: 0;
    flex-shrink: 0;
    position: relative;
}

.demo-result-info .stat-value {
    font-size: var(--result-title-size, 1rem);
    color: var(--text);
    margin-bottom: -0.2rem;
    line-height: 150%;
    letter-spacing: -0.04em;
    font-weight: 400;
    font-family: var(--font-mono);
    position: relative;
}

.demo-result-info .stat-label {
    color: var(--text-secondary);
    font-size: 0.7rem;
    text-transform: none;
    letter-spacing: normal;
    line-height: 1.3125rem;
    font-weight: 400;
    font-family: var(--font-mono);
}

.demo-result-info .stat-value .stat-label.stat-suffix {
    margin-left: 0.1rem;
    font-size: 0.7rem;
    line-height: 1;
}

.demo-result-info .stat-value .stat-value-segment {
    position: relative;
    display: inline-block;
}

.demo-result-info .stat-value .stat-value-number {
    display: inline-block;
    transition: color 0.3s ease, transform 0.3s ease;
}

#demoResults.quote-mode .stat-value-number {
    transition-duration: 0.1s;
}

.demo-result-info .stat-value .stat-prefix {
    position: absolute;
    top: 0.2rem;
    left: -2.3rem;
    transform: scale(0.8);
    line-height: 1;
}

.demo-result-item audio {
    width: 100%;
    height: 48px;
    border-radius: 8px;
    margin-top: 0.5rem;
}

.demo-result-actions {
    display: flex;
    gap: 0.75rem;
    align-items: center;
    margin-left: auto;
}

.demo-download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
    background: transparent;
    color: var(--text);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    transition: color 0.2s ease, transform 0.2s ease;
}

.demo-download-btn:hover {
    color: #ffffff;
    transform: scale(1.05);
}

.demo-download-btn svg {
    width: 16px;
    height: 16px;
}

.demo-error {
    display: none;
    padding: 0.75rem 1rem;
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: 8px;
    color: #ef4444;
    font-size: 1rem;
    line-height: 1.4;
}

.demo-error.active {
    display: block;
}

/* ↓ 1440px 이하 */
@media (max-width: 1440px) {
    .container {
        max-width: 1200px;
        padding: 0 2rem;
    }
}

/* ↓ 1280px 이하 */
@media (max-width: 1280px) {
    .container {
        max-width: 1100px;
        padding: 0 2rem;
    }
}

/* ↓ 768px 이하 */
@media (max-width: 768px) {
    .container {
        padding: 0 1.5rem;
    }

    .btn-secondary {
        width: auto;
        display: inline-block;
    }

    .btn {
        justify-content: center;
    }

    /* Interactive Demo Responsive */
    .interactive-demo {
        padding: 3.0rem 0 0.5rem 0 !important;
    }

    .demo-container {
        padding: 1rem;
    }

    .demo-content {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .demo-controls {
        grid-template-columns: 1fr;
        gap: 0.875rem;
    }

    .demo-params-row {
        grid-template-columns: 1fr;
        gap: 0.875rem;
    }

    .demo-params-row #demoGenerateBtn {
        width: 100%;
        align-self: stretch;
    }

    .demo-param-header {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
        gap: 0.5rem;
        flex-wrap: nowrap;
    }

    .demo-status-box {
        flex-direction: column;
        align-items: flex-start;
        padding: 0.625rem 0.875rem;
    }

    .demo-status-content {
        width: 100%;
    }

    .demo-results {
        min-height: 200px;
        padding: 0;
        overflow-x: hidden;
    }

    .demo-output-section {
        width: 100%;
        min-width: 0;
        overflow: hidden;
    }

    .demo-result-title {
        flex-direction: row;
        flex-wrap: nowrap;
        align-items: center;
        gap: 0.5rem;
    }

    .demo-result-info {
        gap: 0.75rem;
        flex-wrap: wrap;
        justify-content: flex-start;
    }

    .demo-result-info .stat {
        padding: 0;
        flex: 1 1 calc(50% - 0.4rem);
        min-width: 0;
    }

    .demo-result-info .stat:first-child {
        flex-basis: 100%;
    }

    .demo-result-info .stat-value {
        font-size: 1.5rem;
    }

    .demo-result-info .stat-label {
        font-size: 0.7rem;
    }

    .demo-char-counter {
        justify-content: flex-end;
        text-align: right;
        width: 100%;
    }
    
    .stat-value {
        font-size: 5rem;
    }
}

/* Selection */
::selection {
    background: var(--primary);
    color: white;
}


/* Custom Audio Player Styles */
.custom-audio-player {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0;
    background: none;
    border-radius: 0;
    margin-top: 0;
    border: none;
    font-weight: 400;
    grid-column: 3;
    width: 100%;
    flex-wrap: wrap;
}

.player-btn {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: none;
    background: #ddd;
    color: var(--bg-dark);
    font-size: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    flex-shrink: 0;
}

.player-btn svg {
    width: 24px;
    height: 24px;
    display: block;
    pointer-events: none;
    color: #000;
}

.player-btn:hover {
    background: #ffffff;
    transform: scale(1.05);
}

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

.demo-result-item.supertonic-result-item .player-btn:hover,
.demo-result-item.supertonic-result-item .player-btn:focus-visible {
    background: #ffffff;
    color: #000;
}

.custom-audio-player .time-display {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 400;
    min-width: 42px;
    text-align: center;
    flex-shrink: 0;
}

.progress-container {
    flex: 1;
    cursor: pointer;
    padding: 0.5rem 0;
}

.progress-bar {
    width: 100%;
    height: 6px;
    background: #999;
    border-radius: 3px;
    overflow: hidden;
    position: relative;
}

.progress-bar:hover {
    height: 8px;
    transition: height 0.2s ease;
}

.progress-fill {
    width: 0%;
    height: 100%;
    background: #ffffff;
    border-radius: 3px;
    transition: width 0.1s linear;
    position: relative;
}

.progress-fill::after {
    content: '';
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 12px;
    height: 12px;
    background: #ffffff;
    border-radius: 50%;
    box-shadow: 0 0 8px rgba(255, 255, 255, 0.6);
    opacity: 0;
    transition: opacity 0.2s ease;
}

.progress-container:hover .progress-fill::after {
    opacity: 1;
}

.supertonic-result-item {
    --provider-color: #ffffff;
}

#presetControlsRow {
    display: flex;
    gap: 0.4rem;
    margin-top: 0.75rem;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    color: #000;
}

#presetButtonGroup {
    display: flex;
    gap: 0.7rem;
    flex-wrap: wrap;
}

@media (max-width: 768px) {
    .demo-result-item {
        grid-template-columns: 1fr;
        padding: 1rem 0;
    }

    .demo-result-title,
    .demo-result-info,
    .custom-audio-player {
        grid-column: 1;
    }

    .custom-audio-player {
        width: 100%;
        padding: 0 1rem;
    }

    #demoTextInput {
        height: 264.6px;
        min-height: 90px;
    }
}

/* Modal Animations */
@keyframes modalFadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes modalSlideUp {
    from {
        opacity: 0;
        transform: translateY(30px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Language Auto-Detection Toast */
.language-toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: linear-gradient(135deg, rgba(30, 30, 30, 0.95), rgba(20, 20, 20, 0.98));
    color: #fff;
    padding: 0.875rem 1.5rem;
    border-radius: 12px;
    font-family: var(--font-body);
    font-size: 0.9375rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.625rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3), 0 0 0 1px rgba(255, 255, 255, 0.1);
    z-index: 10000;
    opacity: 0;
    visibility: hidden;
    transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1), 
                opacity 0.3s ease,
                visibility 0.3s ease;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.language-toast.show {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.language-toast-icon {
    font-size: 1.125rem;
    filter: drop-shadow(0 0 4px rgba(255, 255, 255, 0.3));
}

.language-toast-message {
    letter-spacing: -0.01em;
}

.language-toast-message strong {
    font-weight: 600;
    color: var(--accent-yellow);
}

@media (max-width: 572px) {
    /* interactive-demo padding 상단 3rem -> 1rem */
    .interactive-demo {
        padding: 1rem 0 0.5rem 0 !important;
    }
    
    /* 1. demo-header: Supertonic 2 이후 문장 줄바꿈, line-height 1.6 -> 1.2 */
    .demo-header {
        line-height: 1.2;
    flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
    
    .demo-header .demo-header-bold {
        display: block;
        margin-bottom: 0.25rem;
    }
    
    .demo-header .demo-header-bold::after {
        content: '';
    }
    
    .demo-header-links {
        align-self: flex-start;
    }
    
    /* 번개 아이콘과 H2 상하정렬: 중앙 -> 상단 */
    .demo-header-icon {
        top: 0;
        transform: translateY(0) scale(1.3);
    }
    
    /* speaker-container, language-info의 레이블과 선택항목간 상하정렬: 중앙 -> 상단 */
    .speaker-container {
        align-items: flex-start;
    }
    
    .language-info {
        align-items: flex-start;
        flex-wrap: nowrap; /* 레이블과 리스트는 같은 줄 유지 */
    }
    
    /* 2. speaker-list, languageList 줄바꿈 - 한 항목씩 줄바꿈 */
    .speaker-list {
        flex-wrap: wrap;
    }
    
    /* language-info 내부의 speaker-list도 동일하게 처리 */
    .language-info .speaker-list {
        flex-wrap: wrap;
    }
    
    /* 3. demo-input-section 폭 대응, padding 제거 */
    .demo-input-section {
        width: 100%;
        max-width: 100%;
    }
    
    /* demo-input-section::after left -27px -> -17px */
    .demo-input-section::after {
        left: -17px;
    }
    
    
    /* 4. demo-params-row: param 1,2는 1열, Generate 버튼은 2열 */
    .demo-params-row {
        grid-template-columns: 1fr 1fr;
        gap: 0.875rem;
    }
    
    .demo-params-row .demo-param:nth-child(1),
    .demo-params-row .demo-param:nth-child(2) {
        grid-column: span 1;
    }
    
    .demo-params-row #demoGenerateBtn {
        grid-column: 1 / -1;
        width: 100%;
    }
    
    /* 5. demoResults 박스 폭 대응 */
    .demo-results {
    width: 100%;
        max-width: 100%;
    }
    
    #demoResults {
    width: 100%;
        max-width: 100%;
    }
}

@media (max-width: 768px) {
    .demo-char-counter.valid {
        justify-content: flex-start;
        text-align: left;
    }
    
    .language-toast {
        bottom: 1.5rem;
        padding: 0.75rem 1.25rem;
    font-size: 0.875rem;
        max-width: calc(100vw - 2rem);
    }
}