:root {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --success: #22c55e;
    --border: #334155;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    background-image: 
        radial-gradient(at 0% 0%, hsla(253,16%,7%,1) 0, transparent 50%), 
        radial-gradient(at 50% 0%, hsla(225,39%,30%,0.2) 0, transparent 50%), 
        radial-gradient(at 100% 0%, hsla(339,49%,30%,0.2) 0, transparent 50%);
}

.container {
    width: 100%;
    max-width: 420px;
    perspective: 1000px;
}

.card {
    background-color: var(--card-bg);
    border-radius: 24px;
    padding: 40px 30px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    border: 1px solid var(--border);
    backdrop-filter: blur(10px);
    transition: all 0.4s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.hidden {
    display: none !important;
}

.header {
    margin-bottom: 30px;
}

.header h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
    background: linear-gradient(135deg, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.header p {
    color: var(--text-muted);
    font-size: 15px;
}

#payment-form {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.input-group {
    position: relative;
    display: flex;
    align-items: center;
    background: rgba(15, 23, 42, 0.6);
    border-radius: 16px;
    border: 2px solid var(--border);
    padding: 10px 20px;
    transition: border-color 0.3s ease;
}

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

.currency {
    font-size: 24px;
    font-weight: 600;
    color: var(--text-muted);
    margin-right: 12px;
}

input[type="number"] {
    background: transparent;
    border: none;
    outline: none;
    color: var(--text-main);
    font-size: 36px;
    font-weight: 700;
    width: 100%;
    font-family: 'Outfit', sans-serif;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

button {
    background: linear-gradient(135deg, var(--primary), #6366f1);
    color: white;
    border: none;
    border-radius: 16px;
    padding: 18px;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    width: 100%;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px -10px var(--primary);
}

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

/* Loader */
#loader {
    margin-top: 20px;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid rgba(255, 255, 255, 0.1);
    border-left-color: var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 15px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

#loader p {
    color: var(--text-muted);
    font-size: 14px;
}

/* Success Animation */
.success-animation {
    margin-bottom: 24px;
}

.checkmark {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: block;
    stroke-width: 4;
    stroke: var(--success);
    stroke-miterlimit: 10;
    margin: 10% auto;
    box-shadow: inset 0px 0px 0px var(--success);
    animation: fill .4s ease-in-out .4s forwards, scale .3s ease-in-out .9s both;
}

.checkmark__circle {
    stroke-dasharray: 166;
    stroke-dashoffset: 166;
    stroke-width: 4;
    stroke-miterlimit: 10;
    stroke: var(--success);
    fill: none;
    animation: stroke 0.6s cubic-bezier(0.65, 0, 0.45, 1) forwards;
}

.checkmark__check {
    transform-origin: 50% 50%;
    stroke-dasharray: 48;
    stroke-dashoffset: 48;
    animation: stroke 0.3s cubic-bezier(0.65, 0, 0.45, 1) 0.8s forwards;
}

@keyframes stroke {
    100% { stroke-dashoffset: 0; }
}

@keyframes scale {
    0%, 100% { transform: none; }
    50% { transform: scale3d(1.1, 1.1, 1); }
}

@keyframes fill {
    100% { box-shadow: inset 0px 0px 0px 40px rgba(34, 197, 94, 0.1); }
}

#success-card h2 {
    font-size: 24px;
    margin-bottom: 12px;
    color: var(--success);
}

#success-card p {
    color: var(--text-muted);
    margin-bottom: 30px;
}