:root {
    --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
    --primary-color: #8b5cf6;
    --primary-hover: #7c3aed;
    --secondary-color: #ec4899;
    --text-main: #f8fafc;
    --text-muted: #cbd5e1;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    --radius: 20px;
}

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

body {
    font-family: 'Outfit', sans-serif;
    color: var(--text-main);
    background: var(--bg-gradient);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: auto; /* Allow scrolling if container is too tall */
    position: relative;
    padding: 20px;
}

.background-animation {
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(139,92,246,0.15) 0%, rgba(30,27,75,0) 50%);
    animation: rotate 30s linear infinite;
    z-index: 0;
    pointer-events: none;
}

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

.container {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    box-shadow: var(--glass-shadow);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    width: 100%;
    max-width: 600px;
    padding: 40px;
    z-index: 1;
    position: relative;
    overflow: hidden;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

h1 {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 10px;
}

#subtitle {
    font-size: 1.2rem;
    color: var(--text-muted);
}

.step {
    transition: opacity 0.4s ease, transform 0.4s ease;
    opacity: 1;
    transform: translateY(0);
}

.step.hidden {
    opacity: 0;
    transform: translateY(20px);
}

.options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.options-reference {
    grid-template-columns: 1fr;
}

.option-btn {
    background: rgba(255,255,255,0.05);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    padding: 20px;
    color: var(--text-main);
    font-size: 1.1rem;
    font-family: 'Outfit', sans-serif;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.option-btn:hover, .option-btn.selected {
    background: rgba(139,92,246,0.2);
    border-color: var(--primary-color);
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(139,92,246,0.2);
}

.option-btn .icon {
    font-size: 2rem;
}

.input-container {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-bottom: 25px;
}

.input-container label {
    font-size: 1.1rem;
    color: var(--text-muted);
}

input[type="date"], input[type="time"], input[type="number"], input[type="month"], input[type="datetime-local"] {
    background: rgba(0,0,0,0.2);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    padding: 15px;
    color: var(--text-main);
    font-family: 'Outfit', sans-serif;
    font-size: 1.2rem;
    outline: none;
    transition: border-color 0.3s ease;
}

input:focus {
    border-color: var(--primary-color);
}

/* Fix for dark input placeholders & icons on modern browsers */
::-webkit-calendar-picker-indicator {
    filter: invert(1);
    cursor: pointer;
}

.nav-buttons {
    display: flex;
    justify-content: space-between;
    margin-top: 20px;
}

.nav-buttons.center {
    justify-content: center;
}

.nav-btn {
    padding: 12px 24px;
    border-radius: 8px;
    font-family: 'Outfit', sans-serif;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.btn-back {
    background: transparent;
    color: var(--text-muted);
    border: 1px solid var(--text-muted);
}

.btn-back:hover {
    background: rgba(255,255,255,0.1);
    color: var(--text-main);
}

.btn-next, .btn-primary {
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
    color: #fff;
    box-shadow: 0 4px 15px rgba(236, 72, 153, 0.3);
}

.btn-next:hover, .btn-primary:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 20px rgba(236, 72, 153, 0.5);
}

.mt-20 {
    margin-top: 20px;
}

/* Result Presentation */
.result-content {
    text-align: center;
}

.result-main {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--secondary-color);
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
    margin-bottom: 15px;
}

.result-card {
    background: rgba(0,0,0,0.2);
    border-radius: 12px;
    padding: 15px;
    border: 1px solid var(--glass-border);
}

.result-card .value {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--primary-color);
}

.result-card .label {
    font-size: 0.9rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* Bonus Calculator specific */
.bonus-result .value {
    color: #10b981; /* Green for success/kilos */
}

@media (max-width: 480px) {
    .options {
        grid-template-columns: 1fr;
    }
}