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

:root {
    --bg-color: #F0EBE4;
    --red: #C41E3A;
    --gold: #D4AF37;
    --green: #2E8B57;
    --text-dark: #2C2C2C;
    --text-light: #6B6B6B;
}

html, body {
    height: 100%;
    overflow: hidden;
    font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background-color: var(--bg-color);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.page {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: opacity 0.6s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.6s ease, transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    background-color: var(--bg-color);
    will-change: opacity, transform;
    backface-visibility: hidden;
}

.page.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.content-center {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    z-index: 10;
}

.page-1 {
    background-color: #000;
}

.cover-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('assets/images/cover.png');
    background-size: cover;
    background-position: center;
    opacity: 0.85;
    will-change: opacity;
}

.main-title {
    color: #fff;
    font-size: 2.5rem;
    font-weight: 300;
    letter-spacing: 0.3em;
    margin-bottom: 1rem;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.5);
    opacity: 0;
    animation: title-appear 1s ease-out 0.5s forwards;
}

.sub-title {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.1rem;
    letter-spacing: 0.2em;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
    opacity: 0;
    animation: title-appear 1s ease-out 0.8s forwards;
}

@keyframes title-appear {
    from {
        opacity: 0;
        transform: translateY(15px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.scroll-indicator {
    position: absolute;
    bottom: 8%;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0;
    animation: title-appear 1s ease-out 1.2s forwards;
}

.arrow {
    display: block;
    font-size: 2rem;
    color: rgba(255, 255, 255, 0.8);
    animation: bounce 2s ease-in-out infinite;
    animation-delay: 2s;
}

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

.section-title {
    font-size: 1.8rem;
    color: var(--text-dark);
    letter-spacing: 0.3em;
    margin-bottom: 3rem;
    font-weight: 400;
}

.sachet-grid {
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
    align-items: center;
}

.sachet-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    cursor: pointer;
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    will-change: transform;
}

.sachet-item img {
    width: 200px;
    height: auto;
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1), filter 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    will-change: transform, filter;
}

@media (min-width: 768px) {
    .sachet-item img {
        width: 280px;
    }
}

.sachet-item:hover img {
    transform: scale(1.08);
}

.sachet-name {
    margin-top: 1rem;
    font-size: 1.2rem;
    color: var(--text-dark);
    letter-spacing: 0.15em;
}

.sachet-item.dimmed img {
    filter: brightness(0.4);
    transform: scale(0.92);
}

.sachet-item.selected img {
    transform: scale(1.15);
    filter: drop-shadow(0 10px 30px rgba(212, 175, 55, 0.4));
}

.sachet-unfold {
    position: relative;
}

.sachet-unfold img {
    width: 280px;
    height: auto;
    transform: scale(0.8) rotate(5deg);
    opacity: 0;
    will-change: transform, opacity;
}

@media (min-width: 768px) {
    .sachet-unfold img {
        width: 380px;
    }
}

.sachet-unfold.unfolding img {
    animation: unfold 1s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

@keyframes unfold {
    0% {
        transform: scale(0.8) rotate(5deg);
        opacity: 0;
    }
    60% {
        transform: scale(1.05) rotate(0deg);
        opacity: 1;
    }
    100% {
        transform: scale(1) rotate(0deg);
        opacity: 1;
    }
}

.sachet-unfold.glowing img {
    animation: glow 2s ease-in-out infinite;
}

@keyframes glow {
    0%, 100% {
        filter: drop-shadow(0 0 20px rgba(212, 175, 55, 0.3));
    }
    50% {
        filter: drop-shadow(0 0 40px rgba(212, 175, 55, 0.6));
    }
}

.golden-particles {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    overflow: hidden;
}

.particle {
    position: absolute;
    width: 4px;
    height: 4px;
    background-color: var(--gold);
    border-radius: 50%;
    opacity: 0;
    animation: float-up 4s ease-in-out infinite;
    will-change: opacity, transform;
}

@keyframes float-up {
    0% {
        opacity: 0;
        transform: translateY(0) scale(0);
    }
    20% {
        opacity: 0.6;
        transform: translateY(-20px) scale(1);
    }
    80% {
        opacity: 0.3;
        transform: translateY(-80px) scale(0.8);
    }
    100% {
        opacity: 0;
        transform: translateY(-120px) scale(0);
    }
}

.blessing-container {
    max-width: 80%;
}

.blessing-text {
    font-size: 1.4rem;
    line-height: 2;
    color: var(--text-dark);
    letter-spacing: 0.15em;
}

@media (min-width: 768px) {
    .blessing-text {
        font-size: 1.8rem;
        line-height: 2.2;
    }
}

.blessing-char {
    display: inline-block;
    opacity: 0;
    transform: translateY(15px);
}

.card-container {
    margin-bottom: 2rem;
}

.card-container img {
    width: 85%;
    max-width: 500px;
    height: auto;
    opacity: 0;
    transform: scale(0.85);
    will-change: transform, opacity;
}

.card-container.appear img {
    animation: card-appear 0.9s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

@keyframes card-appear {
    0% {
        opacity: 0;
        transform: scale(0.85) translateY(30px);
    }
    100% {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

.download-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1rem 3rem;
    background-color: var(--red);
    color: #fff;
    text-decoration: none;
    border-radius: 50px;
    transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 15px rgba(196, 30, 58, 0.3);
    will-change: transform;
}

.download-btn:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 25px rgba(196, 30, 58, 0.5);
}

.btn-text {
    font-size: 1.2rem;
    letter-spacing: 0.2em;
}

.btn-subtext {
    font-size: 0.85rem;
    opacity: 0.8;
    margin-top: 0.3rem;
    letter-spacing: 0.1em;
}

.thank-you-en {
    font-size: 2.5rem;
    color: var(--gold);
    letter-spacing: 0.5em;
    margin-top: 0.5rem;
    font-weight: 300;
}

.farewell-text {
    font-size: 1.3rem;
    color: var(--text-dark);
    margin-top: 1.5rem;
    letter-spacing: 0.1em;
}

.farewell-en {
    font-size: 1rem;
    color: var(--text-light);
    margin-top: 0.5rem;
    letter-spacing: 0.05em;
}

.ritual-text {
    font-size: 1.1rem;
    color: var(--text-dark);
    margin-top: 2rem;
    font-style: italic;
    letter-spacing: 0.1em;
}

.ritual-en {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-top: 0.5rem;
    font-style: italic;
    letter-spacing: 0.05em;
}

.choose-again-btn {
    margin-top: 2.5rem;
    padding: 1rem 2.5rem;
    background-color: transparent;
    border: 2px solid var(--red);
    color: var(--red);
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
    align-items: center;
    font-size: 1.1rem;
    letter-spacing: 0.2em;
    will-change: background-color, color;
}

.choose-again-btn:hover {
    background-color: var(--red);
    color: #fff;
}

.btn-sub {
    font-size: 0.75rem;
    opacity: 0.7;
    margin-top: 0.2rem;
    letter-spacing: 0.1em;
}

.seal {
    position: absolute;
    bottom: 5%;
    left: 50%;
    transform: translateX(-50%);
    text-align: center;
    opacity: 0.3;
}

.seal-cn {
    display: block;
    font-size: 1.1rem;
    color: var(--red);
    letter-spacing: 0.3em;
}

.seal-en {
    display: block;
    font-size: 0.75rem;
    color: var(--text-light);
    margin-top: 0.3rem;
    letter-spacing: 0.15em;
}

.fade-out {
    animation: fade-out 0.5s ease forwards;
}

@keyframes fade-out {
    from { 
        opacity: 1; 
        transform: translateY(0);
    }
    to { 
        opacity: 0; 
        transform: translateY(-20px);
    }
}

@keyframes char-appear {
    from {
        opacity: 0;
        transform: translateY(15px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}