:root {
  --primary: #1b8a5b;
  --primary-hover: #146c46;
  --secondary: #e8f5e9;
  --background: #fcfcfc;
  --surface: #ffffff;
  --text-main: #1f2937;
  --text-muted: #6b7280;
  --border: #e5e7eb;
  --border-focus: #1b8a5b;
  --success: #10b981;
  --danger: #ef4444;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --font-sans: 'Inter', sans-serif;
  --max-width: 1200px;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--background);
  color: var(--text-main);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

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

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

.main-content {
  flex: 1;
}

/* Nav Bar */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background-color: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--primary);
}

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav-link {
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.2s ease;
}

.nav-link.active {
  color: var(--primary);
}

.nav-link:hover {
  color: var(--primary);
}

.api-key-input {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background-color: var(--secondary);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
}

.api-key-input input {
  border: None;
  background: transparent;
  outline: None;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  width: 250px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s ease;
  border: None;
  font-family: var(--font-sans);
  font-size: 1rem;
}

.btn-primary {
  background-color: var(--primary);
  color: white;
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background-color: var(--surface);
  color: var(--text-main);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background-color: #f3f4f6;
}

/* Cards */
.card {
  background-color: var(--surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s ease;
}

.card:hover {
  box-shadow: var(--shadow-md);
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, #1f644b 0%, #154534 100%);
  color: white;
  padding: 5rem 2rem;
  border-radius: var(--radius-xl);
  margin: 2rem auto;
  max-width: var(--max-width);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  background: radial-gradient(circle at top right, rgba(255,255,255,0.1) 0%, transparent 50%);
  pointer-events: None;
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
  letter-spacing: -0.025em;
}

.hero p {
  font-size: 1.125rem;
  color: rgba(255, 255, 255, 0.9);
  max-width: 600px;
  margin: 0 auto;
}

/* Stats Section */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  max-width: var(--max-width);
  margin: -3rem auto 3rem auto;
  padding: 0 2rem;
  position: relative;
  z-index: 10;
}

.stat-card {
  background: var(--surface);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 1rem;
}

.stat-icon {
  background-color: var(--secondary);
  color: var(--primary);
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
}

.stat-info p {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.stat-info h3 {
  font-size: 1.25rem;
  font-weight: 600;
}

/* Features Section */
.section-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 3rem 2rem;
}

.section-title {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 1.5rem;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.feature-card {
  display: flex;
  align-items: flex-start;
  gap: 1.5rem;
}

.feature-icon-wrapper {
  background-color: var(--secondary);
  width: 48px;
  min-width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--primary);
}

.feature-content h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.feature-content p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* How to Use Section */
.steps-container {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.step-item {
  display: flex;
  align-items: flex-start;
  gap: 1.5rem;
  padding: 1.5rem;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}

.step-number {
  background-color: var(--secondary);
  color: var(--primary);
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  font-weight: 700;
  font-size: 0.875rem;
}

.step-content h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.step-content p {
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* Tags */
.tags-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 9999px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-main);
}

.tag .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

/* Callout Banner */
.callout-banner {
  background-color: var(--secondary);
  border: 1px solid #bbf7d0;
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 3rem;
}

.callout-banner p {
  color: var(--primary-hover);
  font-weight: 500;
  font-size: 0.95rem;
}

/* Stepper (Recognition Page) */
.recognition-container {
  max-width: 800px;
  margin: 3rem auto;
  padding: 0 2rem;
}

.recognition-header {
  text-align: center;
  margin-bottom: 3rem;
}

.recognition-header .icon-container {
  width: 80px;
  height: 80px;
  margin: 0 auto 1.5rem auto;
  border-radius: 50%;
  border: 2px solid var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--surface);
  color: var(--primary);
}

.recognition-header h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.recognition-header p {
  color: var(--text-muted);
  font-size: 1.125rem;
}

.stepper {
  display: flex;
  justify-content: center;
  align-items: center;
  margin-bottom: 3rem;
}

.step-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  position: relative;
  min-width: 100px;
}

.step-indicator {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  background-color: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-muted);
  z-index: 2;
  transition: all 0.3s ease;
}

.step-wrapper.active .step-indicator {
  background-color: var(--primary);
  border-color: var(--primary);
  color: white;
}

.step-wrapper.completed .step-indicator {
  background-color: var(--success);
  border-color: var(--success);
  color: white;
}

.step-label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
}

.step-wrapper.active .step-label {
  color: var(--text-main);
  font-weight: 600;
}

.step-divider {
  height: 1px;
  width: 60px;
  background-color: var(--border);
  margin: 0 1rem;
  margin-bottom: 1.5rem;
}

.step-divider.active {
  background-color: var(--primary);
}

/* Upload Zone */
.upload-zone {
  background-color: #f8fafc;
  border: 2px dashed #94a3b8;
  border-radius: var(--radius-lg);
  padding: 4rem 2rem;
  text-align: center;
  transition: all 0.2s ease;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1rem;
}

.upload-zone:hover, .upload-zone.drag-active {
  border-color: var(--primary);
  background-color: var(--secondary);
}

.upload-icon {
  color: var(--primary);
  margin-bottom: 0.5rem;
}

.upload-zone h3 {
  font-size: 1.25rem;
  font-weight: 600;
}

.upload-zone p {
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* Results Display */
.result-card {
  background-color: var(--surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  margin-top: 2rem;
}

.result-header {
  padding: 1.5rem;
  background-color: #f8fafc;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.result-header.healthy {
  background-color: var(--secondary);
}

.result-header.disease {
  background-color: #fef2f2;
}

.result-title {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.result-title h2 {
  font-size: 1.5rem;
  font-weight: 700;
}

.confidence-badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-size: 0.875rem;
  font-weight: 600;
  background-color: white;
  box-shadow: var(--shadow-sm);
}

.result-body {
  padding: 1.5rem;
}

.ai-analytics {
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.ai-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 1rem;
}

.ai-content {
  color: var(--text-main);
  line-height: 1.7;
}

.ai-content h3 {
  font-size: 1.1rem;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
  color: var(--text-main);
}

.ai-content ul {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

.ai-content li {
  margin-bottom: 0.25rem;
}

/* Spinner */
.spinner {
  animation: spin 1s linear infinite;
}

@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}