:root {
    --bg-color: #0b0f19;
    --card-bg: rgba(22, 28, 45, 0.7);
    --text-main: #f0f4f8;
    --text-muted: #94a3b8;
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --good: #10b981;
    --moderate: #f59e0b;
    --unhealthy: #ef4444;
    --hazardous: #7f1d1d;
}

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

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-color);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-image: radial-gradient(circle at top left, #1e293b 0%, transparent 40%),
                      radial-gradient(circle at bottom right, #0f172a 0%, transparent 40%);
}

.container {
    width: 100%;
    max-width: 600px;
    padding: 2rem;
}

.header {
    text-align: center;
    margin-bottom: 2rem;
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, #60a5fa, #c084fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

.header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

.card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 1.5rem;
    padding: 2.5rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 35px 60px -15px rgba(0, 0, 0, 0.6);
}

.form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

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

.input-group label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.input-group input {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid rgba(255, 255, 255, 0.1);
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    color: var(--text-main);
    font-size: 1rem;
    outline: none;
    transition: all 0.2s ease;
}

.input-group input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.3);
}

.btn-predict {
    grid-column: span 2;
    background: var(--primary);
    color: white;
    border: none;
    padding: 1rem;
    border-radius: 0.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s ease, transform 0.1s ease;
    margin-top: 1rem;
}

.btn-predict:hover {
    background: var(--primary-hover);
}

.btn-predict:active {
    transform: scale(0.98);
}

.result-box {
    margin-top: 2rem;
    padding: 2rem;
    border-radius: 1rem;
    text-align: center;
    background: rgba(0,0,0,0.2);
    border: 1px solid rgba(255,255,255,0.05);
    animation: fadeIn 0.5s ease-out;
}

.result-value {
    font-size: 4rem;
    font-weight: 800;
    line-height: 1;
    margin: 1rem 0;
}

.result-status {
    font-size: 1.2rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Status Colors */
.status-good { color: var(--good); }
.status-moderate { color: var(--moderate); }
.status-unhealthy { color: var(--unhealthy); }
.status-hazardous { color: var(--hazardous); }

.loader {
    border: 3px solid rgba(255,255,255,0.1);
    border-top: 3px solid var(--primary);
    border-radius: 50%;
    width: 24px;
    height: 24px;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

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