/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-blue: #2563eb;
    --sky-blue: #38bdf8;
    --fuel-orange: #f59e0b;
    --cloud-white: #f8fafc;
    --text-dark: #1e293b;
    --border-light: #e2e8f0;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.app-header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 2rem 0;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.app-header h1 {
    font-size: 2.5rem;
    color: var(--primary-blue);
    margin-bottom: 0.5rem;
}

/* Main Content */
.app-main {
    padding: 2rem 0;
}

section {
    background: white;
    margin: 2rem 0;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

/* Aircraft Selection */
.aircraft-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.aircraft-card {
    border: 2px solid var(--border-light);
    padding: 1.5rem;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.aircraft-card:hover {
    border-color: var(--primary-blue);
    transform: translateY(-2px);
}

.aircraft-card.selected {
    border-color: var(--primary-blue);
    background: var(--cloud-white);
}

/* Forms */
.flight-form {
    display: grid;
    gap: 1.5rem;
}

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

.input-group label {
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.input-group input {
    padding: 0.75rem;
    border: 2px solid var(--border-light);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary-blue);
}

/* Buttons */
.btn-calculate, .btn-save {
    background: var(--primary-blue);
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: 8px;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-calculate:hover, .btn-save:hover {
    background: #1d4ed8;
    transform: translateY(-1px);
}

/* Results */
.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin: 1.5rem 0;
}

.result-card {
    text-align: center;
    padding: 1.5rem;
    background: var(--cloud-white);
    border-radius: 10px;
    border-left: 4px solid var(--fuel-orange);
}

.result-card h3 {
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.result-card p {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-blue);
}

/* Saved Flights */
.saved-flights-list {
    display: grid;
    gap: 1rem;
}

.saved-flight-item {
    background: var(--cloud-white);
    padding: 1rem;
    border-radius: 8px;
    border-left: 4px solid var(--sky-blue);
}

/* Footer */
.app-footer {
    background: rgba(0, 0, 0, 0.8);
    color: white;
    text-align: center;
    padding: 1.5rem 0;
    margin-top: 3rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }
    
    .app-header h1 {
        font-size: 2rem;
    }
    
    section {
        padding: 1.5rem;
        margin: 1rem 0;
    }
    
    .aircraft-grid {
        grid-template-columns: 1fr;
    }
    
    .results-grid {
        grid-template-columns: 1fr;
    }
}