/* PROPULSE - Professional Blue Navy Theme */
:root {
    --primary: #1a3a5c;
    --primary-light: #2c5f8a;
    --accent: #00b4d8;
    --accent-light: #48cae4;
    --bg: #f0f4f8;
    --card: #ffffff;
    --text: #1e293b;
    --text-muted: #64748b;
    --border: #cbd5e1;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -2px rgba(0,0,0,0.1);
    --radius: 12px;
    --transition: all 0.2s ease;
}

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

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

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 24px;
}

header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: white;
    padding: 40px 0;
    box-shadow: var(--shadow);
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

header .subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
    margin-top: 4px;
}

main {
    display: grid;
    grid-template-columns: 400px 1fr;
    gap: 24px;
    padding: 24px;
}

@media (max-width: 1000px) {
    main { grid-template-columns: 1fr; }
}

.input-panel, .results-panel {
    background: var(--card);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
}

.results-panel {
    min-height: 600px;
}

h2 {
    font-size: 1.25rem;
    color: var(--primary);
    margin: 24px 0 12px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--border);
}

h2:first-child { margin-top: 0; }

.form-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 12px;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.form-group input, .form-group select {
    padding: 10px 12px;
    border: 1.5px solid var(--border);
    border-radius: 8px;
    font-size: 0.95rem;
    transition: var(--transition);
    background: #f8fafc;
}

.form-group input:focus, .form-group select:focus {
    outline: none;
    border-color: var(--accent);
    background: white;
    box-shadow: 0 0 0 3px rgba(0,180,216,0.1);
}

.form-group.checkbox {
    flex-direction: row;
    align-items: center;
}

.form-group.checkbox label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 0.9rem;
}

.form-group.checkbox input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--accent);
}

.appendage-params {
    background: #f8fafc;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 16px;
    margin: 12px 0;
}

.appendage-params h3 {
    font-size: 1rem;
    color: var(--primary);
    margin: 0 0 12px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

.description-panel {
    background: var(--card);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: var(--shadow);
    border-left: 4px solid var(--accent);
}

.description-panel h2 {
    font-size: 1.25rem;
    color: var(--primary);
    margin: 0 0 12px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--border);
}

.description-panel p {
    margin-bottom: 12px;
    line-height: 1.7;
    color: var(--text);
}

.description-panel p:last-child {
    margin-bottom: 0;
}

.buttons {
    display: flex;
    gap: 12px;
    margin-top: 24px;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    flex: 1;
}

.btn.primary {
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-light) 100%);
    color: white;
}

.btn.primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0,180,216,0.3);
}

.btn.secondary {
    background: white;
    color: var(--primary);
    border: 2px solid var(--primary);
}

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

.placeholder {
    text-align: center;
    color: var(--text-muted);
    padding: 60px 20px;
    font-size: 1.1rem;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 16px;
    margin-top: 16px;
}

.result-card {
    background: #f8fafc;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 16px;
}

.result-card h3 {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

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

.result-card .unit {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-left: 4px;
}

.chart-container {
    margin-top: 24px;
    position: relative;
    height: 400px;
}

.loading {
    text-align: center;
    padding: 40px;
    color: var(--text-muted);
}

.spinner {
    border: 4px solid var(--border);
    border-top: 4px solid var(--accent);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 0 auto 16px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.error {
    background: #fef2f2;
    border: 1px solid #fecaca;
    color: var(--danger);
    padding: 16px;
    border-radius: 8px;
    margin-top: 16px;
}

footer {
    text-align: center;
    padding: 24px;
    color: var(--text-muted);
    font-size: 0.9rem;
}

footer a {
    color: var(--accent);
    text-decoration: none;
}

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