body {
    background-color: #ffeff4;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    overflow: hidden;
    text-align: center;
}

.container {
    width: 90%;
    max-width: 600px;
}

h1 {
    color: #ff4d6d;
    margin-bottom: 2rem;
    transition: opacity 0.5s;
}

.gift-container {
    position: relative;
    width: 200px;
    height: 200px;
    margin: 0 auto;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.gift-container:hover {
    transform: scale(1.05);
}

.gift-box {
    position: relative;
    width: 200px;
    height: 200px;
}

.gift-lid {
    position: absolute;
    top: -30px;
    left: -10px;
    width: 220px;
    height: 40px;
    background-color: #ff4d6d;
    border-radius: 4px;
    z-index: 2;
    transition: transform 0.8s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.gift-body {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 200px;
    height: 160px;
    background-color: #ff8fa3;
    border-radius: 0 0 10px 10px;
}

.gift-ribbon-vertical {
    position: absolute;
    left: 90px;
    width: 20px;
    height: 160px;
    background-color: #fff;
    bottom: 0;
}

.gift-ribbon-horizontal {
    position: absolute;
    top: 50px;
    width: 200px;
    height: 20px;
    background-color: #fff;
}

.click-hint {
    margin-top: 1rem;
    color: #ff4d6d;
    font-weight: bold;
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); opacity: 1; }
    50% { transform: scale(1.1); opacity: 0.7; }
    100% { transform: scale(1); opacity: 1; }
}

.hidden {
    display: none;
    opacity: 0;
}

#video-container {
    transition: opacity 1s;
}

.gift-opened .gift-lid {
    transform: translateY(-100px) rotate(-15deg);
    opacity: 0;
}

.gift-opened .gift-body {
    transform: scale(0);
    opacity: 0;
    transition: transform 0.5s, opacity 0.5s;
}

.birthday-header {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.congrats-text {
    color: #ff4d6d;
    margin: 0;
    font-size: 1.6rem;
    animation: pulse 1.5s infinite;
}

.candle {
    font-size: 1.8rem;
    animation: flicker 1s infinite alternate;
}

.heart {
    font-size: 1.5rem;
    animation: heartbeat 1.2s infinite;
}

@keyframes flicker {
    0% { transform: scale(1); opacity: 1; }
    100% { transform: scale(1.15); opacity: 0.8; }
}

@keyframes heartbeat {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.25); }
}

.video-wrapper {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.side-deco {
    font-size: 1.5rem;
    line-height: 2.2;
    text-align: center;
    animation: flicker 1s infinite alternate;
}

.bottom-msg {
    color: #ff4d6d;
    font-size: 1.3rem;
    font-weight: bold;
    margin-top: 1rem;
    animation: pulse 1.5s infinite;
}