/* ===== SentimentLens — Light Theme Design System ===== */

:root {
  /* Colors */
  --color-bg: #F8F9FC;
  --color-surface: #FFFFFF;
  --color-surface-hover: #F1F3F9;
  --color-border: #E2E6EF;
  --color-border-focus: #7C6BF0;
  --color-text-primary: #1A1D2E;
  --color-text-secondary: #6B7394;
  --color-text-muted: #9BA3C2;

  /* Accent */
  --color-accent: #7C6BF0;
  --color-accent-light: #EDE9FE;
  --color-accent-gradient: linear-gradient(135deg, #7C6BF0 0%, #A78BFA 50%, #C4B5FD 100%);
  --color-accent-glow: rgba(124, 107, 240, 0.15);

  /* Semantic */
  --color-positive: #10B981;
  --color-positive-bg: #ECFDF5;
  --color-positive-border: #A7F3D0;
  --color-negative: #F43F5E;
  --color-negative-bg: #FFF1F2;
  --color-negative-border: #FECDD3;

  /* Model tags */
  --color-tfidf: #F59E0B;
  --color-tfidf-bg: #FFFBEB;
  --color-tfidf-border: #FDE68A;
  --color-bert: #6366F1;
  --color-bert-bg: #EEF2FF;
  --color-bert-border: #C7D2FE;

  /* Spacing & Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(26, 29, 46, 0.04), 0 1px 2px rgba(26, 29, 46, 0.02);
  --shadow-md: 0 4px 12px rgba(26, 29, 46, 0.06), 0 2px 4px rgba(26, 29, 46, 0.03);
  --shadow-lg: 0 12px 32px rgba(26, 29, 46, 0.08), 0 4px 8px rgba(26, 29, 46, 0.04);
  --shadow-glow: 0 0 0 4px var(--color-accent-glow);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 400ms cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--color-bg);
  color: var(--color-text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

/* ===== App Layout ===== */
.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ===== Header ===== */
.header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: 0 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, 0.85);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.logo-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: var(--color-accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 18px;
  box-shadow: var(--shadow-sm);
}

.logo-text {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-primary);
  letter-spacing: -0.02em;
}

.logo-text span {
  color: var(--color-accent);
}

.header-badge {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: var(--color-accent-light);
  color: var(--color-accent);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.header-badge .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.8); }
}

/* ===== Hero ===== */
.hero {
  text-align: center;
  padding: 4rem 2rem 2rem;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -60%;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--color-accent-glow) 0%, transparent 70%);
  pointer-events: none;
}

.hero h1 {
  font-size: 2.75rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: var(--color-text-primary);
  margin-bottom: 0.75rem;
  position: relative;
}

.hero h1 .gradient-text {
  background: var(--color-accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.1rem;
  color: var(--color-text-secondary);
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ===== Main Content ===== */
.main {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem;
  width: 100%;
  flex: 1;
}

/* ===== Input Card ===== */
.input-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow-md);
  margin-bottom: 2rem;
  transition: box-shadow var(--transition-normal);
}

.input-card:focus-within {
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  border-color: var(--color-border-focus);
}

.input-card label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.75rem;
}

.textarea-wrapper {
  position: relative;
}

.input-card textarea {
  width: 100%;
  min-height: 140px;
  padding: 1rem;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  color: var(--color-text-primary);
  font-family: inherit;
  font-size: 0.95rem;
  line-height: 1.7;
  resize: vertical;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  outline: none;
}

.input-card textarea:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

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

.char-count {
  position: absolute;
  bottom: 12px;
  right: 14px;
  font-size: 0.72rem;
  color: var(--color-text-muted);
  font-weight: 500;
  pointer-events: none;
}

.input-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 1rem;
  gap: 1rem;
}

.sample-btns {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.sample-btn {
  padding: 6px 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background: var(--color-surface);
  color: var(--color-text-secondary);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: inherit;
}

.sample-btn:hover {
  background: var(--color-surface-hover);
  border-color: var(--color-accent);
  color: var(--color-accent);
  transform: translateY(-1px);
}

.analyze-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 28px;
  background: var(--color-accent-gradient);
  color: white;
  border: none;
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
  font-family: inherit;
  white-space: nowrap;
}

.analyze-btn:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md), 0 4px 20px rgba(124, 107, 240, 0.3);
}

.analyze-btn:active:not(:disabled) {
  transform: translateY(0);
}

.analyze-btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.analyze-btn .btn-icon {
  font-size: 1.1rem;
  transition: transform var(--transition-normal);
}

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

/* Loading spinner */
.spinner {
  width: 18px;
  height: 18px;
  border: 2.5px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ===== Results ===== */
.results-section {
  animation: fadeInUp 0.5s ease-out;
}

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

.results-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 1.25rem;
}

.results-header h2 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text-primary);
}

.results-header .icon {
  font-size: 1.3rem;
}

/* ===== Comparison Grid ===== */
.comparison-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
  margin-bottom: 1.5rem;
}

.model-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.model-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
}

.model-card.tfidf::before {
  background: linear-gradient(90deg, #F59E0B, #FBBF24);
}

.model-card.bert::before {
  background: linear-gradient(90deg, #6366F1, #818CF8);
}

.model-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.model-tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 1rem;
}

.model-tag.tfidf {
  background: var(--color-tfidf-bg);
  color: var(--color-tfidf);
  border: 1px solid var(--color-tfidf-border);
}

.model-tag.bert {
  background: var(--color-bert-bg);
  color: var(--color-bert);
  border: 1px solid var(--color-bert-border);
}

.sentiment-result {
  text-align: center;
  padding: 0.75rem 0;
}

.sentiment-emoji {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  display: block;
  animation: bounceIn 0.5s ease-out;
}

@keyframes bounceIn {
  0% { transform: scale(0); }
  50% { transform: scale(1.2); }
  100% { transform: scale(1); }
}

.sentiment-label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.sentiment-label.positive {
  background: var(--color-positive-bg);
  color: var(--color-positive);
  border: 1px solid var(--color-positive-border);
}

.sentiment-label.negative {
  background: var(--color-negative-bg);
  color: var(--color-negative);
  border: 1px solid var(--color-negative-border);
}

/* Confidence meter */
.confidence-section {
  margin-top: 1.25rem;
}

.confidence-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
}

.confidence-label {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-secondary);
}

.confidence-value {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-text-primary);
}

.confidence-bar {
  width: 100%;
  height: 8px;
  background: var(--color-bg);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.confidence-fill {
  height: 100%;
  border-radius: var(--radius-full);
  transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
}

.confidence-fill.positive {
  background: linear-gradient(90deg, #34D399, #10B981);
}

.confidence-fill.negative {
  background: linear-gradient(90deg, #FB7185, #F43F5E);
}

.latency {
  display: flex;
  align-items: center;
  gap: 5px;
  margin-top: 0.75rem;
  font-size: 0.72rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

.latency .icon {
  font-size: 0.85rem;
}

/* ===== Agreement Banner ===== */
.agreement-banner {
  padding: 1rem 1.5rem;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.88rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  animation: fadeInUp 0.5s ease-out 0.2s both;
}

.agreement-banner.agree {
  background: var(--color-positive-bg);
  color: var(--color-positive);
  border: 1px solid var(--color-positive-border);
}

.agreement-banner.disagree {
  background: var(--color-negative-bg);
  color: var(--color-negative);
  border: 1px solid var(--color-negative-border);
}

.agreement-banner .icon {
  font-size: 1.2rem;
}

/* ===== Text Preview ===== */
.text-preview {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  animation: fadeInUp 0.5s ease-out 0.3s both;
}

.text-preview-header {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 0.6rem;
}

.text-preview p {
  font-size: 0.88rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
  font-style: italic;
}

/* ===== Error State ===== */
.error-banner {
  background: var(--color-negative-bg);
  border: 1px solid var(--color-negative-border);
  border-radius: var(--radius-md);
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--color-negative);
  font-size: 0.88rem;
  font-weight: 500;
  margin-bottom: 1.5rem;
  animation: fadeInUp 0.3s ease-out;
}

.error-banner .icon {
  font-size: 1.2rem;
}

/* ===== Footer ===== */
.footer {
  text-align: center;
  padding: 2rem;
  border-top: 1px solid var(--color-border);
  margin-top: auto;
}

.footer p {
  font-size: 0.78rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

.footer a {
  color: var(--color-accent);
  text-decoration: none;
  font-weight: 600;
}

.footer a:hover {
  text-decoration: underline;
}

/* ===== Responsive ===== */
@media (max-width: 700px) {
  .hero h1 {
    font-size: 2rem;
  }

  .hero p {
    font-size: 0.95rem;
  }

  .comparison-grid {
    grid-template-columns: 1fr;
  }

  .input-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .sample-btns {
    justify-content: center;
  }

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

  .header-inner {
    padding: 0 0.5rem;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.65rem;
  }

  .main {
    padding: 1rem;
  }

  .input-card {
    padding: 1.25rem;
  }
}