:root {
  --navy: #001f3f;
  --cyan: #00bcd4;
  --cyan-dark: #0097a7;
  --white: #ffffff;
  --gray-50: #f8fafc;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1e293b;
  --danger: #ef4444;
  --success: #22c55e;
  --warning: #f59e0b;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --radius: 8px;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: var(--font); background: linear-gradient(135deg, var(--navy), #003366); min-height: 100vh; color: var(--gray-800); }
.app-container { min-height: 100vh; display: flex; flex-direction: column; }

/* Header */
.header { background: var(--white); padding: 0.75rem 2rem; display: flex; justify-content: space-between; align-items: center; box-shadow: var(--shadow); }
.logo { display: flex; align-items: center; gap: 0.75rem; }
.logo-icon { font-size: 1.5rem; }
.logo-text { font-size: 1.15rem; font-weight: 700; color: var(--navy); }
.header-actions { display: flex; align-items: center; gap: 0.75rem; }
.user-info { font-size: 0.85rem; color: var(--gray-600); }

/* Auth */
.auth-required { flex: 1; display: flex; align-items: center; justify-content: center; padding: 2rem; }
.auth-card { background: var(--white); padding: 3rem; border-radius: var(--radius); text-align: center; box-shadow: var(--shadow-lg); max-width: 400px; }
.auth-card h2 { color: var(--navy); margin-bottom: 1rem; }
.auth-card p { color: var(--gray-600); }

/* Layout */
.main-content { flex: 1; padding: 1.5rem; max-width: 1100px; margin: 0 auto; width: 100%; }
.two-col { display: grid; grid-template-columns: 280px 1fr; gap: 1.5rem; align-items: start; }

/* Sidebar */
.sidebar { display: flex; flex-direction: column; gap: 1rem; }
.card { background: var(--white); border-radius: var(--radius); padding: 1.25rem; box-shadow: var(--shadow-lg); }
.card h2 { color: var(--navy); font-size: 1rem; margin-bottom: 0.75rem; padding-bottom: 0.5rem; border-bottom: 2px solid var(--gray-100); }
.card h3 { color: var(--navy); font-size: 0.85rem; margin-bottom: 0.5rem; }

/* Reports list */
.report-list { list-style: none; max-height: 300px; overflow-y: auto; }
.report-list li { padding: 0.5rem; border-bottom: 1px solid var(--gray-100); cursor: pointer; border-radius: 4px; transition: background 0.15s; font-size: 0.85rem; }
.report-list li:hover { background: var(--gray-50); }
.report-list li.active { background: rgba(0,188,212,0.1); border-color: var(--cyan); }
.report-name { font-weight: 600; color: var(--navy); }
.report-meta { font-size: 0.75rem; color: var(--gray-500); margin-top: 2px; }
.report-list-empty { font-size: 0.85rem; color: var(--gray-500); font-style: italic; padding: 0.5rem 0; }

/* Buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 0.4rem; padding: 0.5rem 1rem; border: none; border-radius: var(--radius); font-family: var(--font); font-size: 0.85rem; font-weight: 500; cursor: pointer; transition: all 0.2s; text-decoration: none; }
.btn-primary { background: linear-gradient(135deg, var(--cyan), var(--cyan-dark)); color: var(--white); }
.btn-primary:hover { transform: translateY(-1px); box-shadow: var(--shadow); }
.btn-secondary { background: var(--gray-100); color: var(--gray-700); border: 1px solid var(--gray-200); }
.btn-secondary:hover { background: var(--gray-200); }
.btn-danger { background: var(--danger); color: var(--white); }
.btn-danger:hover { opacity: 0.9; }
.btn-sm { padding: 0.35rem 0.65rem; font-size: 0.78rem; }
.btn-block { width: 100%; }
.btn-group { display: flex; gap: 0.5rem; flex-wrap: wrap; }

/* Form elements */
.form-section { margin-bottom: 1.25rem; }
.form-label { display: block; font-weight: 600; color: var(--navy); margin-bottom: 0.35rem; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.04em; }
.form-hint { font-size: 0.75rem; color: var(--gray-500); font-weight: 400; text-transform: none; letter-spacing: 0; }
.form-input, .form-select { width: 100%; padding: 0.55rem 0.75rem; border: 2px solid var(--gray-200); border-radius: var(--radius); font-family: var(--font); font-size: 0.9rem; transition: all 0.2s; background: var(--white); }
.form-input:focus, .form-select:focus { outline: none; border-color: var(--cyan); box-shadow: 0 0 0 3px rgba(0,188,212,0.1); }
.form-input-sm { padding: 0.4rem 0.6rem; font-size: 0.85rem; }
.form-row { display: flex; gap: 0.75rem; align-items: flex-end; }
.form-row > * { flex: 1; }
.form-check { display: flex; align-items: center; gap: 0.5rem; cursor: pointer; }
.form-check input[type="checkbox"] { width: 18px; height: 18px; accent-color: var(--cyan); }
.form-check label { font-size: 0.88rem; cursor: pointer; }

/* Mode toggle */
.mode-toggle { display: flex; border: 2px solid var(--gray-200); border-radius: var(--radius); overflow: hidden; }
.mode-toggle button { flex: 1; padding: 0.6rem; border: none; background: var(--white); font-family: var(--font); font-size: 0.85rem; font-weight: 600; cursor: pointer; transition: all 0.2s; color: var(--gray-600); }
.mode-toggle button.active { background: var(--navy); color: var(--white); }

/* Calculator sections */
.calc-section { background: var(--white); border-radius: var(--radius); margin-bottom: 1rem; box-shadow: var(--shadow); overflow: hidden; }
.calc-section-header { background: var(--navy); color: var(--white); padding: 0.6rem 1rem; font-size: 0.85rem; font-weight: 600; display: flex; justify-content: space-between; align-items: center; }
.calc-section-header .tag { background: rgba(255,255,255,0.2); border-radius: 12px; padding: 0.1rem 0.6rem; font-size: 0.72rem; font-weight: 500; }
.calc-section-body { padding: 1rem; }

/* Load row */
.load-row { display: flex; align-items: center; gap: 0.5rem; margin-bottom: 0.5rem; padding: 0.4rem 0; }
.load-row label { flex: 1; font-size: 0.85rem; }
.load-row .load-input { width: 90px; }
.load-row .load-breaker { width: 75px; }
.load-row .load-demand { min-width: 85px; text-align: right; font-weight: 600; color: var(--navy); font-size: 0.85rem; }
.load-row .unit { font-size: 0.78rem; color: var(--gray-500); min-width: 25px; }

/* Equipment list */
.equipment-item { display: flex; align-items: center; gap: 0.5rem; margin-bottom: 0.5rem; padding: 0.5rem; background: var(--gray-50); border-radius: 6px; border: 1px solid var(--gray-200); }
.equipment-item input[type="text"] { flex: 1; padding: 0.4rem 0.6rem; border: 1px solid var(--gray-200); border-radius: 4px; font-size: 0.85rem; font-family: var(--font); }
.equipment-item input[type="text"]:focus { outline: none; border-color: var(--cyan); }
.equipment-item input[type="number"], .equipment-item select { width: 80px; padding: 0.4rem 0.5rem; border: 1px solid var(--gray-200); border-radius: 4px; font-size: 0.85rem; font-family: var(--font); }
.equipment-item input[type="number"]:focus, .equipment-item select:focus { outline: none; border-color: var(--cyan); }
.equipment-item .btn-remove { padding: 0.25rem 0.5rem; font-size: 0.78rem; background: var(--danger); color: white; border: none; border-radius: 4px; cursor: pointer; line-height: 1; }
.equipment-item .btn-remove:hover { opacity: 0.85; }

/* Info box */
.info-box { padding: 0.6rem 0.75rem; border-radius: 6px; font-size: 0.82rem; margin-top: 0.5rem; }
.info-box.info { background: #eaf2f8; color: var(--navy); border-left: 3px solid var(--cyan); }
.info-box.warn { background: #fef9e7; color: #92400e; border-left: 3px solid var(--warning); }

/* Results card */
.results-card { background: var(--white); border-radius: var(--radius); box-shadow: var(--shadow-lg); overflow: hidden; border: 2px solid var(--navy); }
.results-card .calc-section-header { font-size: 0.95rem; }
.result-table { width: 100%; border-collapse: collapse; font-size: 0.85rem; }
.result-table th { text-align: left; padding: 0.5rem 0.75rem; background: var(--gray-50); border-bottom: 2px solid var(--gray-200); font-weight: 600; color: var(--navy); font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.03em; }
.result-table td { padding: 0.4rem 0.75rem; border-bottom: 1px solid var(--gray-100); }
.result-table td:last-child { text-align: right; font-weight: 600; }
.result-table tr.total-row td { border-top: 2px solid var(--navy); font-weight: 700; font-size: 0.9rem; color: var(--navy); padding-top: 0.6rem; }

/* Service size badge */
.service-badge { text-align: center; padding: 1.25rem; }
.service-badge .size { font-size: 2.5rem; font-weight: 800; color: var(--navy); line-height: 1; }
.service-badge .size-label { font-size: 0.82rem; color: var(--gray-500); margin-top: 0.25rem; }
.service-badge .size-detail { font-size: 0.85rem; color: var(--gray-600); margin-top: 0.5rem; font-weight: 500; }
.service-badge.ok { border-top: 4px solid var(--success); }
.service-badge.warn { border-top: 4px solid var(--warning); }
.service-badge.over { border-top: 4px solid var(--danger); }

/* Breaker panel */
.panel-summary { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.75rem; margin-top: 0.75rem; }
.panel-stat { text-align: center; padding: 0.75rem; background: var(--gray-50); border-radius: 6px; }
.panel-stat .num { font-size: 1.5rem; font-weight: 700; color: var(--navy); }
.panel-stat .lbl { font-size: 0.72rem; color: var(--gray-500); text-transform: uppercase; }
.panel-stat.danger .num { color: var(--danger); }

/* Toast */
.toast { position: fixed; bottom: 1.5rem; right: 1.5rem; background: var(--navy); color: var(--white); padding: 0.75rem 1.25rem; border-radius: var(--radius); box-shadow: var(--shadow-lg); font-size: 0.88rem; z-index: 2000; transform: translateY(100px); opacity: 0; transition: all 0.3s; }
.toast.show { transform: translateY(0); opacity: 1; }
.toast.error { background: var(--danger); }
.toast.success { background: var(--success); }

/* Disclaimer */
.disclaimer { background: #fef9e7; border-left: 3px solid var(--warning); padding: 0.5rem 0.75rem; font-size: 0.78rem; margin-bottom: 1rem; border-radius: 0 4px 4px 0; color: #92400e; }

/* Print */
@media print {
  body { background: white; }
  .header, .sidebar, .btn, .disclaimer { display: none; }
  .two-col { grid-template-columns: 1fr; }
  .calc-section, .results-card { break-inside: avoid; box-shadow: none; border: 1px solid #ccc; }
  .main-content { max-width: 100%; padding: 0; }
}

@media (max-width: 900px) {
  .two-col { grid-template-columns: 1fr; }
  .sidebar { order: -1; }
  .header { padding: 0.75rem 1rem; flex-wrap: wrap; gap: 0.5rem; }
  .panel-summary { grid-template-columns: 1fr; }
  .form-row { flex-direction: column; }
}