:root {
    --primary-color: #6366f1;
    --secondary-color: #a855f7;
    --accent-color: #ec4899;
    --background-dark: #0f172a;
    --text-light: #f8fafc;
    --text-muted: #94a3b8;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --input-bg: rgba(15, 23, 42, 0.6);
    --error-color: #ef4444;
    --success-color: #22c55e;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Outfit', sans-serif;
}

body {
    background-color: var(--background-dark);
    color: var(--text-light);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    position: relative;
}

/* Background Animation */
.background-shapes {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.shape {
    position: absolute;
    filter: blur(100px);
    opacity: 0.6;
    animation: float 10s infinite ease-in-out alternate;
}

.shape-1 {
    top: 10%;
    left: 10%;
    width: 300px;
    height: 300px;
    background: var(--primary-color);
    animation-delay: 0s;
}

.shape-2 {
    bottom: 20%;
    right: 10%;
    width: 250px;
    height: 250px;
    background: var(--secondary-color);
    animation-delay: -5s;
}

.shape-3 {
    top: 40%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 200px;
    height: 200px;
    background: var(--accent-color);
    animation-delay: -2s;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(20px, 40px) scale(1.1); }
}

/* Container & Card */
.container {
    width: 100%;
    max-width: 450px;
    padding: 20px;
    position: relative;
    z-index: 1;
}

.card {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    padding: 40px 30px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    text-align: center;
    transition: transform 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
}

h1 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 5px;
    background: linear-gradient(135deg, #ddd6fe 0%, #ffffff 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 30px;
}

/* Input Styles */
.converter-box {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.input-group {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
}

label {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 500;
    margin-left: 4px;
}

input[type="number"] {
    width: 100%;
    padding: 16px;
    background: var(--input-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    color: white;
    font-size: 1.1rem;
    outline: none;
    transition: all 0.3s ease;
}

input[type="number"]:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.2);
}

/* Units Config */
.units-container {
    display: flex;
    align-items: flex-end;
    gap: 10px;
}

.select-group {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
}

select {
    width: 100%;
    padding: 14px;
    background: var(--input-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    color: white;
    font-size: 0.95rem;
    outline: none;
    cursor: pointer;
    transition: all 0.3s ease;
    appearance: none; /* Remove default arrow */
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 16px;
}

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

select option {
    background-color: var(--background-dark);
}

.exchange-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 48px; /* Match select height roughly */
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.3s ease;
}

.exchange-icon:hover {
    color: white;
    transform: rotate(180deg);
}

/* Button */
button {
    margin-top: 10px;
    width: 100%;
    padding: 16px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

button:active {
    transform: translateY(0);
}

/* Result Box */
.result-box {
    margin-top: 30px;
    padding: 20px;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 16px;
    border: 1px solid var(--glass-border);
    animation: fadeIn 0.5s ease;
}

.result-box.hidden {
    display: none;
}

.result-text {
    font-size: 2.5rem;
    font-weight: 600;
    color: white;
    margin-bottom: 5px;
    text-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
}

.result-detail {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Alert Box */
.alert-box {
    margin-top: 20px;
    padding: 12px;
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.2);
    border-radius: 12px;
    color: #fca5a5;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    animation: shake 0.4s ease-in-out;
}

.alert-box.hidden {
    display: none;
}

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

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

/* Responsive */
@media (max-width: 480px) {
    .card {
        padding: 30px 20px;
    }
    
    .units-container {
        flex-direction: column;
        align-items: stretch;
    }
    
    .exchange-icon {
        width: 100%;
        height: 32px;
        transform: rotate(90deg);
    }

    .exchange-icon:hover {
        transform: rotate(270deg);
    }
}