:root {
  /* Color Palette - Slate & Blue */
  --primary: #2563eb; /* Royal Blue */
  --primary-dark: #1d4ed8;
  --primary-light: #eff6ff;

  --bg-body: #f1f5f9; /* Light Grey Background */
  --bg-card: #ffffff;

  --text-main: #0f172a; /* Dark Slate */
  --text-muted: #64748b; /* Muted Slate */

  --border: #e2e8f0;
  --border-hover: #cbd5e1;

  /* Status Colors */
  --success-bg: #dcfce7;
  --success-text: #14532d;
  --warning-bg: #fef3c7;
  --warning-text: #78350f;
  --danger-bg: #fee2e2;
  --danger-text: #7f1d1d;

  /* Effects */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --radius: 0.75rem;
  --transition: all 0.2s ease-in-out;
}

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

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-body);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* --- Navigation --- */
nav {
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow-sm);
}

.nav-links {
  display: flex;
  gap: 0.5rem;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  padding: 0.5rem 1rem;
  border-radius: 0.5rem;
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--primary);
  background: var(--primary-light);
}

.nav-links a.active {
  background: var(--primary);
  color: white;
}

.nav-auth {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.username {
  color: var(--text-main);
  font-weight: 600;
  font-size: 0.9rem;
}

.role-badge {
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.role-badge-user {
  background: #dbeafe;
  color: #1e40af;
  border: 1px solid #93c5fd;
}

.role-badge-scientist {
  background: #fef3c7;
  color: #92400e;
  border: 1px solid #fcd34d;
}

.logout-btn {
  color: var(--danger-text);
  border: 1px solid #fecaca;
  background: #fff1f2;
  padding: 0.4rem 1rem;
  border-radius: 0.5rem;
  font-size: 0.9rem;
  text-decoration: none;
  font-weight: 600;
  transition: var(--transition);
}

.logout-btn:hover {
  background: var(--danger-text);
  color: white;
  border-color: var(--danger-text);
}

/* --- Layout --- */
h1 {
  font-size: 1.875rem;
  font-weight: 800;
  color: var(--text-main);
  margin: 2rem auto 1rem;
  max-width: 1200px;
  padding: 0 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.card {
  background: var(--bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border);
  margin: 0 auto 1.5rem;
  padding: 2rem;
  max-width: 1200px;
}

h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.75rem;
}

/* --- Upload Zone --- */
.upload-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  background: #f8fafc;
  padding: 3rem 2rem;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
}

.upload-zone:hover,
.upload-zone.dragover {
  border-color: var(--primary);
  background: var(--primary-light);
}

.upload-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
  display: block;
}

input[type="file"] {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

/* --- Buttons --- */
.btn-primary {
  background: var(--primary);
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: 0.5rem;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  box-shadow: 0 2px 4px rgba(37, 99, 235, 0.2);
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
  box-shadow: 0 4px 6px rgba(37, 99, 235, 0.3);
}

.btn-primary:disabled {
  background: var(--text-muted);
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

/* --- Results Grid --- */
.analysis-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
  gap: 1.5rem;
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 1rem;
}

.metric-box {
  background: #f8fafc;
  border: 1px solid var(--border);
  padding: 1rem;
  border-radius: 0.5rem;
  text-align: center;
  transition: var(--transition);
}

.metric-box:hover {
  border-color: var(--primary);
  background: white;
  box-shadow: var(--shadow-sm);
}

.metric-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.metric-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
}

/* --- Images --- */
.image-comparison {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.image-box img {
  width: 100%;
  border-radius: 0.5rem;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

/* --- Hazard Banner --- */
.risk-banner {
  padding: 1.5rem;
  border-radius: var(--radius);
  text-align: center;
  font-weight: 700;
  font-size: 1.1rem;
  margin: 0 auto 1.5rem;
  max-width: 1200px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  box-shadow: var(--shadow-md);
}
.risk-banner.low {
  background: var(--success-bg);
  color: var(--success-text);
  border: 1px solid #86efac;
}
.risk-banner.medium {
  background: var(--warning-bg);
  color: var(--warning-text);
  border: 1px solid #fcd34d;
}
.risk-banner.high {
  background: var(--danger-bg);
  color: var(--danger-text);
  border: 1px solid #fca5a5;
}

/* --- Badges --- */
.badge {
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
}
.badge.ok {
  background: var(--success-bg);
  color: var(--success-text);
}
.badge.err {
  background: var(--danger-bg);
  color: var(--danger-text);
}

/* --- Utility --- */
.table {
  width: 100%;
  border-collapse: collapse;
}
.table td {
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
}
.table td strong {
  color: var(--text-main);
}
pre {
  background: #1e293b;
  color: #e2e8f0;
  padding: 1rem;
  border-radius: 0.5rem;
  overflow-x: auto;
}

@media (max-width: 768px) {
  .image-comparison,
  .analysis-container {
    grid-template-columns: 1fr;
  }
  .nav-links {
    display: none;
  }
}