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

        :root {
            --primary-color: #667eea;
            --secondary-color: #764ba2;
            --success-color: #48bb78;
            --glass-bg: rgba(255, 255, 255, 0.1);
            --glass-border: rgba(255, 255, 255, 0.2);
            --text-color: #ffffff;
            --text-dark: #1a202c;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
            min-height: 100vh;
            background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 20px;
            position: relative;
            overflow-x: hidden;
        }

        /* Animated background shapes */
        .bg-shape {
            position: absolute;
            border-radius: 50%;
            filter: blur(40px);
            opacity: 0.6;
            animation: float 20s infinite ease-in-out;
        }

        .shape1 {
            width: 300px;
            height: 300px;
            background: linear-gradient(135deg, #667eea, #764ba2);
            top: -150px;
            left: -150px;
            animation-delay: 0s;
        }

        .shape2 {
            width: 200px;
            height: 200px;
            background: linear-gradient(135deg, #f093fb, #f5576c);
            bottom: -100px;
            right: -100px;
            animation-delay: 5s;
        }

        .shape3 {
            width: 250px;
            height: 250px;
            background: linear-gradient(135deg, #4facfe, #00f2fe);
            top: 50%;
            left: 50%;
            animation-delay: 10s;
        }

        @keyframes float {
            0%, 100% {
                transform: translate(0, 0) rotate(0deg);
            }
            33% {
                transform: translate(30px, -30px) rotate(120deg);
            }
            66% {
                transform: translate(-20px, 20px) rotate(240deg);
            }
        }

        /* Glass container */
        .donation-container {
            background: var(--glass-bg);
            -webkit-backdrop-filter: blur(10px);
            backdrop-filter: blur(10px);
            border: 1px solid var(--glass-border);
            border-radius: 20px;
            padding: 40px;
            max-width: 500px;
            width: 100%;
            box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
            position: relative;
            z-index: 1;
            animation: slideUp 0.5s ease-out;
        }

        @keyframes slideUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        h1 {
            color: var(--text-color);
            text-align: center;
            margin-bottom: 10px;
            font-size: 2rem;
            font-weight: 700;
        }

        .subtitle {
            color: rgba(255, 255, 255, 0.8);
            text-align: center;
            margin-bottom: 30px;
            font-size: 0.95rem;
        }

        /* Amount buttons grid */
        .amount-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
            gap: 15px;
            margin-bottom: 25px;
        }

        .amount-btn {
            background: var(--glass-bg);
            -webkit-backdrop-filter: blur(5px);
            backdrop-filter: blur(5px);
            border: 2px solid var(--glass-border);
            border-radius: 12px;
            padding: 18px;
            color: var(--text-color);
            font-size: 1.2rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
        }

        .amount-btn::before {
            content: '';
            position: absolute;
            top: 50%;
            left: 50%;
            width: 0;
            height: 0;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.3);
            transform: translate(-50%, -50%);
            transition: width 0.6s, height 0.6s;
        }

        .amount-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
            border-color: rgba(255, 255, 255, 0.4);
        }

        .amount-btn:active::before {
            width: 300px;
            height: 300px;
        }

        .amount-btn.selected {
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            border-color: transparent;
            animation: pulse 0.5s ease-out;
        }

        @keyframes pulse {
            0% {
                transform: scale(0.95);
            }
            50% {
                transform: scale(1.05);
            }
            100% {
                transform: scale(1);
            }
        }

        /* Custom amount input */
        .custom-amount {
            margin-bottom: 25px;
        }

        .custom-amount label {
            color: var(--text-color);
            display: block;
            margin-bottom: 10px;
            font-weight: 500;
        }

        .input-wrapper {
            position: relative;
        }

        .input-wrapper span {
            position: absolute;
            left: 20px;
            top: 50%;
            transform: translateY(-50%);
            color: var(--text-color);
            font-size: 1.2rem;
            font-weight: 600;
        }

        input[type="number"] {
            width: 100%;
            padding: 15px 15px 15px 45px;
            background: var(--glass-bg);
            -webkit-backdrop-filter: blur(5px);
            backdrop-filter: blur(5px);
            border: 2px solid var(--glass-border);
            border-radius: 12px;
            color: var(--text-color);
            font-size: 1.1rem;
            transition: all 0.3s ease;
            -webkit-appearance: none;
            -moz-appearance: textfield;
            -webkit-appearance: none; /* Safari, Chrome */
            -moz-appearance: textfield; /* Firefox */
            appearance: none;
        }

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

        input[type="number"]:focus {
            outline: none;
            border-color: rgba(255, 255, 255, 0.4);
            box-shadow: 0 0 20px rgba(255, 255, 255, 0.1);
        }

        input[type="number"]::placeholder {
            color: rgba(255, 255, 255, 0.5);
        }

        /* Submit button */
        .submit-btn {
            width: 100%;
            padding: 18px;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            border: none;
            border-radius: 12px;
            color: white;
            font-size: 1.1rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            position: relative;
            overflow: hidden;
        }

        .submit-btn::after {
            content: '';
            position: absolute;
            top: 50%;
            left: 50%;
            width: 0;
            height: 0;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.3);
            transform: translate(-50%, -50%);
            transition: width 0.8s, height 0.8s;
        }

        .submit-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
        }

        .submit-btn:active::after {
            width: 600px;
            height: 600px;
        }

        .submit-btn:disabled {
            opacity: 0.6;
            cursor: not-allowed;
        }

        /* Success animation */
        .success-animation {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0, 0, 0, 0.8);
            z-index: 1000;
            justify-content: center;
            align-items: center;
        }

        .success-animation.show {
            display: flex;
            animation: fadeIn 0.3s ease-out;
        }

        @keyframes fadeIn {
            from {
                opacity: 0;
            }
            to {
                opacity: 1;
            }
        }

        .success-content {
            background: var(--glass-bg);
            -webkit-backdrop-filter: blur(10px);
            backdrop-filter: blur(10px);
            border: 1px solid var(--glass-border);
            border-radius: 20px;
            padding: 40px;
            text-align: center;
            animation: scaleIn 0.5s ease-out;
        }

        @keyframes scaleIn {
            from {
                transform: scale(0.8);
                opacity: 0;
            }
            to {
                transform: scale(1);
                opacity: 1;
            }
        }

        .checkmark {
            width: 80px;
            height: 80px;
            margin: 0 auto 20px;
            position: relative;
        }

        .checkmark-circle {
            stroke-dasharray: 166;
            stroke-dashoffset: 166;
            stroke-width: 2;
            stroke-miterlimit: 10;
            stroke: var(--success-color);
            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;
            stroke: var(--success-color);
            fill: none;
            animation: stroke 0.3s cubic-bezier(0.65, 0, 0.45, 1) 0.8s forwards;
        }

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

        .success-message {
            color: var(--text-color);
            font-size: 1.5rem;
            font-weight: 600;
            margin-bottom: 10px;
        }

        .success-submessage {
            color: rgba(255, 255, 255, 0.8);
        }

        /* Loading spinner */
        .spinner {
            display: none;
            width: 20px;
            height: 20px;
            border: 3px solid rgba(255, 255, 255, 0.3);
            border-top-color: white;
            border-radius: 50%;
            animation: spin 0.8s linear infinite;
            margin: 0 auto;
        }

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

        .submit-btn.loading .btn-text {
            display: none;
        }

        .submit-btn.loading .spinner {
            display: block;
        }

        /* Mobile optimizations */
        @media (max-width: 480px) {
            .donation-container {
                padding: 30px 20px;
            }

            h1 {
                font-size: 1.6rem;
            }

            .amount-grid {
                grid-template-columns: repeat(2, 1fr);
            }

            .amount-btn {
                font-size: 1.1rem;
                padding: 15px;
            }
        }

        /* iOS specific */
        @supports (-webkit-touch-callout: none) {
            input[type="number"] {
                font-size: 16px;
            }
        }