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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    max-width: 1200px;
    width: 100%;
    overflow: hidden;
    animation: slideIn 0.6s ease-out;
}

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

.header {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    padding: 40px 30px;
    text-align: center;
    color: white;
}

.logo {
    width: 150px;
    height: 150px;
    margin: 0 auto 20px;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

.logo img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    filter: drop-shadow(0 5px 15px rgba(0,0,0,0.2));
}

h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.slogan {
    font-size: 1.3em;
    font-weight: 300;
    line-height: 1.6;
    margin-top: 15px;
    background: rgba(255,255,255,0.2);
    padding: 15px;
    border-radius: 10px;
}

.slogan strong {
    font-weight: 700;
    text-decoration: underline;
}

.content {
    padding: 40px 30px;
}

.section {
    margin-bottom: 30px;
}

.section h2 {
    color: #667eea;
    margin-bottom: 15px;
    font-size: 1.8em;
    border-left: 5px solid #f5576c;
    padding-left: 15px;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.feature-card {
    background: linear-gradient(135deg, #667eea15 0%, #764ba215 100%);
    padding: 20px;
    border-radius: 15px;
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 2px solid transparent;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(102, 126, 234, 0.3);
    border-color: #667eea;
}

.feature-icon {
    font-size: 2.5em;
    margin-bottom: 10px;
}

.feature-card h3 {
    color: #764ba2;
    margin-bottom: 8px;
    font-size: 1.2em;
}

.feature-card p {
    color: #666;
    font-size: 0.95em;
    line-height: 1.5;
}

.qr-section {
    background: linear-gradient(135deg, #ffecd2 0%, #fcb69f 100%);
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    margin: 30px 0;
}

.qr-code {
    background: white;
    padding: 20px;
    border-radius: 15px;
    display: inline-block;
    margin: 20px auto;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.qr-code img {
    width: 300px;
    height: 300px;
    display: block;
}

.funny-notes {
    background: #fff9e6;
    border-left: 5px solid #ffd700;
    padding: 20px;
    margin: 20px 0;
    border-radius: 0 10px 10px 0;
}

.funny-notes h3 {
    color: #ff6b6b;
    margin-bottom: 15px;
    font-size: 1.3em;
}

.funny-notes ul {
    list-style: none;
    padding-left: 0;
}

.funny-notes li {
    padding: 10px 0;
    padding-left: 30px;
    position: relative;
    color: #555;
    line-height: 1.6;
}

.funny-notes li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #4CAF50;
    font-weight: bold;
    font-size: 1.2em;
}

.disclaimer {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 10px;
    margin-top: 20px;
    font-size: 0.9em;
    color: #666;
    text-align: center;
    font-style: italic;
}

.cta-button {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 15px 40px;
    border: none;
    border-radius: 50px;
    font-size: 1.2em;
    font-weight: bold;
    cursor: pointer;
    display: inline-block;
    margin: 20px auto;
    transition: all 0.3s ease;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.cta-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.6);
}

@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    .container {
        border-radius: 15px;
    }

    .header {
        padding: 30px 20px;
    }

    .logo {
        width: 120px;
        height: 120px;
    }

    h1 {
        font-size: 2em;
    }
    
    .slogan {
        font-size: 1em;
        padding: 12px;
    }

    .content {
        padding: 25px 20px;
    }

    .section h2 {
        font-size: 1.5em;
        padding-left: 12px;
    }
    
    .features {
        grid-template-columns: 1fr;
        gap: 15px;
    }

    .feature-card {
        padding: 18px;
    }

    .feature-icon {
        font-size: 2em;
    }

    .qr-section {
        padding: 25px 20px;
    }
    
    .qr-code img {
        width: 250px;
        height: 250px;
    }

    .qr-code {
        padding: 15px;
    }

    .cta-button {
        padding: 12px 30px;
        font-size: 1em;
        width: 100%;
    }

    .funny-notes {
        padding: 15px;
    }

    .funny-notes h3 {
        font-size: 1.1em;
    }

    .funny-notes li {
        font-size: 0.95em;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.6em;
    }

    .slogan {
        font-size: 0.9em;
    }

    .logo {
        width: 100px;
        height: 100px;
    }

    .section h2 {
        font-size: 1.3em;
    }

    .qr-code img {
        width: 200px;
        height: 200px;
    }

    .feature-card h3 {
        font-size: 1.1em;
    }

    .feature-card p {
        font-size: 0.9em;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .container {
        max-width: 900px;
    }

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

    h1 {
        font-size: 2.2em;
    }
}

.pulse {
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

/* Donation Notification Dialog */
.donate-notification {
    position: fixed;
    bottom: 20px;
    left: 20px;
    z-index: 10000;
    opacity: 0;
    transform: translateX(-100%);
    transition: all 0.5s ease-in-out;
    pointer-events: none;
}

.donate-notification.show {
    opacity: 1;
    transform: translateX(0);
    pointer-events: auto;
}

.donate-notification-content {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    font-size: 1.1em;
    font-weight: bold;
    max-width: 400px;
    animation: slideInLeft 0.5s ease-out;
    border: 3px solid rgba(255, 255, 255, 0.3);
}

@keyframes slideInLeft {
    from {
        transform: translateX(-100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@media (max-width: 768px) {
    .donate-notification {
        bottom: 15px;
        left: 15px;
        right: 15px;
    }
    
    .donate-notification-content {
        max-width: 100%;
        padding: 15px 20px;
        font-size: 1em;
    }
}

/* Fireworks Animation */
.fireworks-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    overflow: hidden;
}

.firework-particle {
    position: absolute;
    border-radius: 50%;
    opacity: 0;
    animation: firework-burst 3s ease-out forwards;
    animation-delay: var(--delay, 0s);
    background: radial-gradient(circle, var(--color, #fff) 0%, var(--color, #fff) 40%, transparent 70%);
    box-shadow: 
        0 0 10px var(--color, #fff),
        0 0 20px var(--color, #fff),
        0 0 30px var(--color, #fff),
        0 0 40px var(--color, #fff);
    will-change: transform, opacity;
    filter: blur(0.5px);
    transform: translateZ(0); /* GPU acceleration */
    backface-visibility: hidden;
    perspective: 1000px;
}

/* Mobile optimization - giảm effects để tăng performance */
.firework-particle.mobile-optimized {
    background: var(--color, #fff);
    box-shadow: 
        0 0 8px var(--color, #fff),
        0 0 16px var(--color, #fff);
    filter: none; /* Loại bỏ blur trên mobile */
    animation: firework-burst-mobile 2.5s ease-out forwards;
}

.firework-particle.sparkle {
    box-shadow: 
        0 0 5px var(--color, #fff),
        0 0 10px var(--color, #fff),
        0 0 15px var(--color, #fff),
        0 0 20px var(--color, #fff),
        0 0 30px var(--color, #fff);
    animation: firework-burst-sparkle 3s ease-out forwards;
    animation-delay: var(--delay, 0s);
}

@keyframes firework-burst {
    0% {
        opacity: 1;
        transform: translate3d(0, 0, 0) scale(1) rotate(0deg);
        filter: blur(0.5px) brightness(1.5);
    }
    15% {
        opacity: 1;
        filter: blur(0.5px) brightness(1.8);
    }
    50% {
        opacity: 0.9;
        filter: blur(1px) brightness(1.2);
    }
    100% {
        opacity: 0;
        transform: 
            translate3d(var(--distance-x, 0), calc(-1 * var(--distance-y, 0)), 0) 
            scale(0.2) 
            rotate(720deg);
        filter: blur(2px) brightness(0.5);
    }
}

@keyframes firework-burst-sparkle {
    0% {
        opacity: 1;
        transform: translate3d(0, 0, 0) scale(1) rotate(0deg);
        filter: blur(0px) brightness(2);
    }
    20% {
        opacity: 1;
        filter: blur(0px) brightness(2.5);
        transform: translate3d(0, 0, 0) scale(1.2) rotate(180deg);
    }
    50% {
        opacity: 0.8;
        filter: blur(0.5px) brightness(1.5);
    }
    100% {
        opacity: 0;
        transform: 
            translate3d(var(--distance-x, 0), calc(-1 * var(--distance-y, 0)), 0) 
            scale(0.1) 
            rotate(1080deg);
        filter: blur(3px) brightness(0.3);
    }
}

/* Mobile animation - đơn giản hơn, không có blur */
@keyframes firework-burst-mobile {
    0% {
        opacity: 1;
        transform: translate3d(0, 0, 0) scale(1) rotate(0deg);
    }
    20% {
        opacity: 1;
    }
    100% {
        opacity: 0;
        transform: 
            translate3d(var(--distance-x, 0), calc(-1 * var(--distance-y, 0)), 0) 
            scale(0.2) 
            rotate(360deg);
    }
}