:root {
  --primary: #10B981;
  --primary-dark: #059669;
  --primary-bg: #F0FDF4;
  --primary-light: #D1FAE5;
  --danger: #EF4444;
  --danger-bg: #FEF2F2;
  --warning: #F59E0B;
  --warning-bg: #FFFBEB;
  --info: #3B82F6;
  --info-bg: #EFF6FF;
  --text: #111827;
  --text-secondary: #6B7280;
  --text-muted: #9CA3AF;
  --border: #E5E7EB;
  --border-light: #F3F4F6;
  --bg: #FFFFFF;
  --bg-secondary: #F9FAFB;
  --bg-tertiary: #F3F4F6;
  --shadow-xs: 0 1px 2px 0 rgb(0 0 0 / 0.02);
  --shadow-sm: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  --radius-sm: 6px;
  --radius: 8px;
  --radius-md: 10px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing: 0.75rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: linear-gradient(135deg, var(--primary-bg) 0%, var(--bg) 50%, #FAFBFC 100%);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.6;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: var(--spacing-xl) var(--spacing-md);
}

.header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing);
}

.logo span {
  font-size: 1.875rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.header-subtitle {
  color: var(--text-secondary);
  font-size: 1rem;
  font-weight: 500;
  margin-top: var(--spacing-xs);
}

.explainer-section {
  text-align: center;
  margin-bottom: var(--spacing-xl);
  padding: 0 var(--spacing-md);
}

.explainer-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: var(--spacing-sm);
  line-height: 1.4;
}

.explainer-subtitle {
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-weight: 400;
  line-height: 1.5;
}

.upload-card {
  background: var(--bg);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  border: 1px solid var(--border-light);
  overflow: hidden;
  backdrop-filter: blur(10px);
}

.upload-area {
  padding: var(--spacing-xl);
  text-align: center;
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  margin: var(--spacing-xl);
  background: linear-gradient(135deg, var(--bg) 0%, var(--bg-secondary) 100%);
}

.upload-area:hover {
  border-color: var(--primary);
  background: var(--primary-bg);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.upload-area.dragover {
  border-color: var(--primary);
  background: var(--primary-light);
  transform: scale(1.02);
}

.upload-icon {
  margin-bottom: var(--spacing);
  transition: transform 0.3s ease;
}

.upload-area:hover .upload-icon {
  transform: scale(1.1);
}

.upload-area h2 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-sm);
  color: var(--text);
  font-weight: 600;
}

.upload-area p {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
  font-size: 1rem;
  font-weight: 400;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: white;
  border: none;
  padding: var(--spacing) var(--spacing-xl);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.2) 0%, transparent 50%);
  opacity: 0;
  transition: opacity 0.3s ease;
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}

.btn-primary:hover::before {
  opacity: 1;
}

.btn-primary:active {
  transform: translateY(-1px);
}

.supported-formats {
  display: flex;
  gap: var(--spacing-sm);
  justify-content: center;
  margin-top: var(--spacing-lg);
  flex-wrap: wrap;
}

.supported-formats span {
  padding: var(--spacing-xs) var(--spacing);
  background: var(--bg-tertiary);
  border-radius: 9999px;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
  border: 1px solid var(--border-light);
  transition: all 0.2s ease;
}

.supported-formats span:hover {
  background: var(--primary-bg);
  color: var(--primary);
  border-color: var(--primary);
}

.loading {
  display: none;
  padding: var(--spacing-2xl);
  text-align: center;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-md);
}

.loading.show {
  display: flex;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border-light);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

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

.loading-text {
  color: var(--text-secondary);
  font-size: 1rem;
  font-weight: 500;
}

.results {
  display: none;
  padding: var(--spacing-xl);
}

.results.show {
  display: block;
  animation: slideInUp 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.result-header {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-md);
  border-bottom: 2px solid var(--border-light);
}

.result-header > div:nth-child(2) {
  width: 100%;
}

.result-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  flex-shrink: 0;
  font-weight: 600;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-light);
}

.result-icon.valid {
  background: linear-gradient(135deg, var(--primary-bg) 0%, var(--primary-light) 100%);
  color: var(--primary-dark);
  border-color: var(--primary);
}

.result-icon.invalid {
  background: linear-gradient(135deg, var(--danger-bg) 0%, #FDE8E8 100%);
  color: var(--danger);
  border-color: var(--danger);
}

.result-icon.warning {
  background: linear-gradient(135deg, var(--warning-bg) 0%, #FEF3C7 100%);
  color: var(--warning);
  border-color: var(--warning);
}

.result-icon.expired {
  background: linear-gradient(135deg, #FFF7ED 0%, #FFEDD5 100%);
  color: var(--warning);
  border-color: var(--warning);
}

.result-icon.info {
  background: linear-gradient(135deg, var(--info-bg) 0%, #DBEAFE 100%);
  color: var(--info);
  border-color: var(--info);
}

.result-header h3 {
  font-size: 1.5rem;
  margin: 0;
  font-weight: 600;
  color: var(--text);
  line-height: 1.3;
}

.integrity-badge {
  padding: 0.5rem 1rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  white-space: nowrap;
  box-shadow: var(--shadow-sm);
  border: 1px solid;
  flex-shrink: 0;
}

.integrity-badge.intact {
  background: linear-gradient(135deg, var(--primary-bg) 0%, var(--primary-light) 100%);
  color: var(--primary-dark);
  border-color: var(--primary);
}

.integrity-badge.modified {
  background: linear-gradient(135deg, var(--danger-bg) 0%, #FDE8E8 100%);
  color: var(--danger);
  border-color: var(--danger);
}

.integrity-badge.unknown {
  background: linear-gradient(135deg, var(--warning-bg) 0%, #FEF3C7 100%);
  color: var(--warning);
  border-color: var(--warning);
}

/* CRITICAL FIX: Professional detail rows */
.detail-row {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--spacing-lg);
  padding: var(--spacing) 0;
  border-bottom: 1px solid var(--border-light);
  font-size: 0.9375rem;
  line-height: 1.5;
  min-height: 2.5rem;
}

.detail-row:last-child {
  border-bottom: none;
}

.detail-label {
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  font-size: 0.8125rem;
  letter-spacing: 0.05em;
  flex-shrink: 0;
  min-width: 120px;
  display: flex;
  align-items: center;
}

.detail-value {
  color: var(--text);
  font-weight: 500;
  text-align: right;
  word-wrap: break-word;
  flex: 1;
  min-width: 0;
  font-size: 0.9375rem;
  line-height: 1.4;
}

/* Enhanced sections */
.integrity-section,
.signature-info-section {
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-lg);
  background: linear-gradient(135deg, var(--bg) 0%, var(--bg-secondary) 100%);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
  border-left: 4px solid var(--primary);
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
}

.integrity-section::before,
.signature-info-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--primary), transparent);
}

/* Premium signature cards */
.signature-card {
  margin-bottom: var(--spacing-lg);
  padding: var(--spacing-lg);
  background: linear-gradient(135deg, var(--bg) 0%, var(--bg-secondary) 100%);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
  border-left: 4px solid var(--primary);
  box-shadow: var(--shadow);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

.signature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--primary), var(--primary-dark));
}

.signature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary);
}

.signature-card > div:first-child {
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  font-size: 1.125rem;
  color: var(--text);
  padding-bottom: var(--spacing);
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.signature-card > div:first-child::before {
  content: '🔐';
  font-size: 1rem;
}

.chain-toggle {
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--primary);
  font-weight: 600;
  font-size: 0.9375rem;
  user-select: none;
  padding: var(--spacing-sm) 0;
  transition: all 0.2s ease;
  border-radius: var(--radius-sm);
}

.chain-toggle:hover {
  background: var(--primary-bg);
  padding-left: var(--spacing-sm);
  padding-right: var(--spacing-sm);
  color: var(--primary-dark);
}

.chain-panel {
  display: none;
  margin-top: var(--spacing-md);
  padding: var(--spacing-md);
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  font-size: 0.875rem;
  animation: slideDown 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.chain-panel.show {
  display: block;
}

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

.chain-panel > div {
  margin-bottom: var(--spacing-md);
  padding: var(--spacing-md);
  background: var(--bg);
  border-radius: var(--radius-sm);
  font-size: 0.8125rem;
  border-left: 3px solid var(--primary);
  box-shadow: var(--shadow-xs);
}

.chain-panel > div:last-child {
  margin-bottom: 0;
}

.error-message {
  display: none;
  margin: var(--spacing-xl);
  padding: var(--spacing-lg);
  border-radius: var(--radius-lg);
  border: 1px solid;
  font-size: 0.9375rem;
  box-shadow: var(--shadow-sm);
}

.error-message.show {
  display: block;
  animation: slideInUp 0.3s ease;
}

.error-message.error {
  background: linear-gradient(135deg, var(--danger-bg) 0%, #FEFEFE 100%);
  border-color: #FECACA;
  color: #991B1B;
  border-left: 4px solid var(--danger);
}

.error-message.warning {
  background: linear-gradient(135deg, var(--warning-bg) 0%, #FEFEFE 100%);
  border-color: #FDE68A;
  color: #92400E;
  border-left: 4px solid var(--warning);
}

.error-message.info {
  background: linear-gradient(135deg, var(--info-bg) 0%, #FEFEFE 100%);
  border-color: #DBEAFE;
  color: #1E40AF;
  border-left: 4px solid var(--info);
}

.error-main {
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  font-size: 1rem;
}

.error-sub {
  margin-top: var(--spacing);
  font-size: 0.875rem;
}

.error-help {
  margin-top: var(--spacing);
  font-size: 0.875rem;
  opacity: 0.85;
}

.footer {
  text-align: center;
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  color: var(--text-secondary);
  font-size: 0.875rem;
  line-height: 1.6;
  border-top: 1px solid var(--border-light);
}

.footer p {
  margin: var(--spacing-sm) 0;
}

.footer a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
  transition: all 0.2s ease;
}

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

@media (max-width: 768px) {
  body {
    font-size: 14px;
  }
  
  .container {
    padding: var(--spacing-lg) var(--spacing-md);
  }

  .explainer-title {
    font-size: 1.125rem;
  }

  .explainer-subtitle {
    font-size: 0.8125rem;
  }
  
  .upload-area {
    padding: var(--spacing-lg) var(--spacing-md);
    margin: var(--spacing-md);
  }
  
  .results {
    padding: var(--spacing-lg);
  }
  

  .result-header h3 {
    font-size: 1.25rem;
  }

  .integrity-badge {
    font-size: 0.75rem;
    padding: 0.375rem 0.75rem;
  }
  
  .detail-row {
    flex-direction: column;
    gap: var(--spacing-xs);
    align-items: flex-start;
    padding: var(--spacing) 0;
  }
  
  .detail-label {
    font-size: 0.75rem;
    min-width: auto;
  }
  
  .detail-value {
    text-align: left;
    font-size: 0.875rem;
    padding-left: 0;
  }
  
  .signature-card {
    padding: var(--spacing-md);
  }

  .chain-panel {
    padding: var(--spacing-md);
    font-size: 0.8125rem;
  }

  .supported-formats {
    gap: var(--spacing-xs);
  }

  .supported-formats span {
    font-size: 0.75rem;
    padding: var(--spacing-xs) var(--spacing-sm);
  }
}

@media (max-width: 480px) {
  .container {
    padding: var(--spacing-md) var(--spacing-sm);
  }
  
  .logo span {
    font-size: 1.5rem;
  }
  
  .header-subtitle {
    font-size: 0.875rem;
  }

  .explainer-title {
    font-size: 1rem;
  }

  .explainer-subtitle {
    font-size: 0.75rem;
  }
  
  .upload-area h2 {
    font-size: 1.25rem;
  }
  
  .btn-primary {
    font-size: 0.875rem;
    padding: var(--spacing-sm) var(--spacing-lg);
  }
}