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

body {
    min-height: 100vh;
    background: linear-gradient(to bottom, #0a0e27 0%, #1a0f2e 50%, #0d0221 100%);
    overflow: hidden;
    font-family: 'Georgia', serif;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

/* 星空背景层 */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        radial-gradient(2px 2px at 20% 30%, white, transparent),
        radial-gradient(2px 2px at 60% 70%, white, transparent),
        radial-gradient(1px 1px at 50% 50%, white, transparent),
        radial-gradient(1px 1px at 80% 10%, white, transparent),
        radial-gradient(2px 2px at 90% 60%, white, transparent),
        radial-gradient(1px 1px at 33% 80%, white, transparent),
        radial-gradient(1px 1px at 15% 60%, white, transparent);
    background-size: 200% 200%, 200% 200%, 300% 300%, 250% 250%, 200% 200%, 280% 280%, 220% 220%;
    background-position: 0% 0%, 40% 40%, 50% 50%, 80% 10%, 0% 50%, 60% 70%, 90% 40%;
    animation: twinkle 3s ease-in-out infinite;
    pointer-events: none;
    opacity: 0.8;
}

/* 更多星星层 */
body::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        radial-gradient(1px 1px at 10% 20%, rgba(255, 255, 255, 0.8), transparent),
        radial-gradient(1px 1px at 70% 80%, rgba(255, 255, 255, 0.6), transparent),
        radial-gradient(1px 1px at 40% 40%, rgba(255, 255, 255, 0.7), transparent),
        radial-gradient(2px 2px at 85% 30%, rgba(255, 255, 255, 0.9), transparent),
        radial-gradient(1px 1px at 25% 90%, rgba(255, 255, 255, 0.5), transparent),
        radial-gradient(1px 1px at 95% 70%, rgba(255, 255, 255, 0.6), transparent),
        radial-gradient(1px 1px at 55% 15%, rgba(255, 255, 255, 0.8), transparent);
    background-size: 250% 250%, 280% 280%, 200% 200%, 220% 220%, 300% 300%, 240% 240%, 260% 260%;
    background-position: 10% 20%, 70% 80%, 40% 40%, 85% 30%, 25% 90%, 95% 70%, 55% 15%;
    animation: twinkle 4s ease-in-out infinite reverse;
    pointer-events: none;
    opacity: 0.6;
}

/* 星星闪烁动画 */
@keyframes twinkle {
    0%, 100% {
        opacity: 0.3;
        transform: scale(1);
    }
    50% {
        opacity: 1;
        transform: scale(1.2);
    }
}

.hidden {
    display: none !important;
}

/* 音乐加载提示 */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(10, 14, 39, 0.95);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 10000;
    transition: opacity 0.5s ease;
}

.loading-overlay.fade-out {
    opacity: 0;
    pointer-events: none;
}

.loading-content {
    text-align: center;
    color: #fff;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    margin: 0 auto 20px;
    border: 4px solid rgba(255, 255, 255, 0.2);
    border-top: 4px solid #fff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading-text {
    font-size: 20px;
    font-family: 'KaiTi', '楷体', 'STKaiti', serif;
    margin-bottom: 10px;
    letter-spacing: 2px;
}

.loading-progress {
    font-size: 16px;
    color: #aaa;
    font-family: Arial, sans-serif;
}

/* 信件容器 */
.letter-container {
    position: relative;
    z-index: 20;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

/* 信封样式 */
.envelope {
    position: relative;
    width: 350px;
    height: 220px;
    cursor: pointer;
    transition: all 0.5s ease;
    animation: envelopeFloat 3s ease-in-out infinite;
}

@keyframes envelopeFloat {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(2deg); }
}

.envelope:hover {
    transform: translateY(-10px) scale(1.05) !important;
}

.envelope-body {
    position: absolute;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #f5e6d3 0%, #e8d4b8 100%);
    border-radius: 5px;
    box-shadow:
        0 20px 60px rgba(0, 0, 0, 0.4),
        0 10px 30px rgba(0, 0, 0, 0.3),
        inset 0 0 50px rgba(255, 255, 255, 0.3);
    border: 2px solid #d4b896;
}

.envelope-flap {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #e8d4b8 0%, #d4b896 100%);
    clip-path: polygon(0 0, 50% 45%, 100% 0);
    border-radius: 5px 5px 0 0;
    box-shadow:
        0 5px 15px rgba(0, 0, 0, 0.3),
        inset 0 -10px 20px rgba(0, 0, 0, 0.1);
    transition: all 0.8s cubic-bezier(0.34, 1.56, 0.64, 1);
    transform-origin: top center;
    z-index: 2;
}

.envelope.open .envelope-flap {
    transform: rotateX(180deg);
}

.envelope-seal {
    position: absolute;
    top: 35%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 50px;
    height: 50px;
    background: radial-gradient(circle, #ff69b4 0%, #ff1493 100%);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 28px;
    box-shadow:
        0 5px 20px rgba(255, 20, 147, 0.5),
        inset 0 -2px 10px rgba(0, 0, 0, 0.2);
    z-index: 3;
    animation: sealGlow 2s ease-in-out infinite;
}

@keyframes sealGlow {
    0%, 100% {
        box-shadow:
            0 5px 20px rgba(255, 20, 147, 0.5),
            0 0 30px rgba(255, 105, 180, 0.3),
            inset 0 -2px 10px rgba(0, 0, 0, 0.2);
    }
    50% {
        box-shadow:
            0 5px 30px rgba(255, 20, 147, 0.8),
            0 0 50px rgba(255, 105, 180, 0.6),
            inset 0 -2px 10px rgba(0, 0, 0, 0.2);
    }
}

.envelope-text {
    position: absolute;
    bottom: 30%;
    left: 50%;
    transform: translateX(-50%);
    color: #8b6f47;
    font-size: 20px;
    font-family: 'KaiTi', '楷体', 'STKaiti', serif;
    letter-spacing: 3px;
    text-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
    z-index: 1;
}

/* 信纸样式 */
.letter-paper {
    position: absolute;
    width: 900px;
    max-width: 90vw;
    height: auto;
    min-height: 750px;
    max-height: 85vh;
    background:
        linear-gradient(to bottom,
            #fffaf0 0%,
            #faf0e6 100%);
    padding: 70px 80px 60px;
    border-radius: 15px;
    box-shadow:
        0 30px 80px rgba(0, 0, 0, 0.5),
        0 15px 40px rgba(0, 0, 0, 0.3),
        inset 0 0 100px rgba(139, 111, 71, 0.08);
    border: 2px solid #d4b896;
    animation: letterUnfold 1.5s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
    transform-origin: top center;
    position: relative;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    box-sizing: border-box;
}

/* 信纸装饰边框 */
.letter-paper::before {
    content: '';
    position: absolute;
    top: 20px;
    left: 20px;
    right: 20px;
    bottom: 20px;
    border: 1px solid rgba(139, 111, 71, 0.2);
    border-radius: 10px;
    pointer-events: none;
}

/* 信纸顶部装饰 */
.letter-paper::after {
    content: '✿ ❀ ✿';
    position: absolute;
    top: 35px;
    left: 50%;
    transform: translateX(-50%);
    color: #d4a574;
    font-size: 24px;
    letter-spacing: 20px;
    opacity: 0.6;
}

@keyframes letterUnfold {
    0% {
        opacity: 0;
        transform: scaleY(0) translateY(-100px);
    }
    100% {
        opacity: 1;
        transform: scaleY(1) translateY(0);
    }
}

.letter-content {
    color: #2c2416;
    font-size: 17px;
    line-height: 2.0;
    font-family: 'KaiTi', '楷体', 'STKaiti', serif;
    white-space: pre-wrap;
    letter-spacing: 1.5px;
    margin-bottom: 20px;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
    position: relative;
    z-index: 1;
    flex: 1;
}

.letter-signature {
    color: #5d4e37;
    font-size: 20px;
    font-family: 'KaiTi', '楷体', 'STKaiti', serif;
    text-align: right;
    margin-top: 30px;
    letter-spacing: 3px;
    font-style: italic;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
    position: relative;
    z-index: 1;
}

.continue-btn {
    display: block;
    margin: 30px auto 0;
    background: linear-gradient(135deg, #ff69b4 0%, #ff1493 100%);
    color: white;
    border: none;
    padding: 15px 50px;
    font-size: 18px;
    border-radius: 50px;
    cursor: pointer;
    font-family: 'KaiTi', '楷体', 'STKaiti', serif;
    letter-spacing: 3px;
    box-shadow:
        0 10px 30px rgba(255, 105, 180, 0.5),
        0 0 40px rgba(255, 20, 147, 0.3);
    transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    animation: btnAppear 0.8s ease-out forwards;
    flex-shrink: 0;
}

@keyframes btnAppear {
    0% {
        opacity: 0;
        transform: scale(0);
    }
    100% {
        opacity: 1;
        transform: scale(1);
    }
}

.continue-btn:hover {
    transform: translateY(-5px) scale(1.05);
    box-shadow:
        0 15px 40px rgba(255, 105, 180, 0.7),
        0 0 60px rgba(255, 20, 147, 0.5);
}

.continue-btn:active {
    transform: translateY(-2px) scale(1.02);
}

/* 星空背景 */
.stars, .stars2, .stars3 {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.stars {
    background: transparent;
}

.stars::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        radial-gradient(circle, rgba(255, 255, 255, 0.9) 0%, transparent 1px),
        radial-gradient(circle, rgba(255, 255, 255, 0.8) 0%, transparent 1px),
        radial-gradient(circle, rgba(255, 255, 255, 0.7) 0%, transparent 0.5px);
    background-size: 300px 300px, 400px 400px, 200px 200px;
    background-position: 0 0, 50px 60px, 130px 270px;
    background-repeat: repeat;
    animation: starTwinkle 4s ease-in-out infinite;
}

.stars2 {
    background: transparent;
}

.stars2::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        radial-gradient(circle, rgba(255, 255, 255, 0.6) 0%, transparent 1px),
        radial-gradient(circle, rgba(200, 200, 255, 0.5) 0%, transparent 0.5px);
    background-size: 350px 350px, 250px 250px;
    background-position: 100px 100px, 200px 50px;
    background-repeat: repeat;
    animation: starTwinkle 5s ease-in-out infinite;
    animation-delay: 1.5s;
}

.stars3 {
    background: transparent;
}

.stars3::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        radial-gradient(circle, rgba(255, 192, 203, 0.4) 0%, transparent 1px),
        radial-gradient(circle, rgba(221, 160, 221, 0.3) 0%, transparent 0.5px);
    background-size: 450px 450px, 320px 320px;
    background-position: 150px 200px, 50px 150px;
    background-repeat: repeat;
    animation: starTwinkle 6s ease-in-out infinite;
    animation-delay: 3s;
}

@keyframes starTwinkle {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
}

/* 火焰效果 */
.fire-container {
    position: relative;
    z-index: 10;
    animation: fireBurnOut 3s ease-out forwards;
}

@keyframes fireBurnOut {
    0% {
        opacity: 1;
        transform: scale(1);
    }
    70% {
        opacity: 1;
        transform: scale(1);
    }
    85% {
        opacity: 0.6;
        transform: scale(0.8);
    }
    100% {
        opacity: 0;
        transform: scale(0.3);
    }
}

.fire {
    position: relative;
    width: 500px;
    height: 500px;
}

.fire-center {
    position: absolute;
    bottom: 50px;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    height: 100%;
}

.fire-main {
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 180px;
    height: 350px;
    background:
        radial-gradient(ellipse 50% 80% at 50% 100%,
            #fff 0%,
            #fff 2%,
            #ffeb3b 5%,
            #ffc107 10%,
            #ff9800 20%,
            #ff5722 35%,
            #f44336 50%,
            #d32f2f 65%,
            rgba(183, 28, 28, 0.8) 80%,
            transparent 100%
        );
    border-radius: 50% 50% 50% 50% / 60% 60% 40% 40%;
    animation:
        flameFlicker 0.1s ease-in-out infinite alternate,
        flameSway 2s ease-in-out infinite;
    filter: blur(3px);
}

.fire-main:nth-child(2) {
    width: 220px;
    height: 380px;
    animation-delay: 0.05s, 0.3s;
    opacity: 0.7;
    filter: blur(5px);
}

.fire-main:nth-child(3) {
    width: 150px;
    height: 320px;
    animation-delay: 0.08s, 0.6s;
    opacity: 0.8;
    filter: blur(2px);
}

@keyframes flameFlicker {
    0% {
        transform: translateX(-50%) scaleY(1) scaleX(1);
    }
    100% {
        transform: translateX(-50%) scaleY(1.08) scaleX(0.95);
    }
}

@keyframes flameSway {
    0%, 100% {
        transform: translateX(-50%) rotate(-3deg);
    }
    50% {
        transform: translateX(-50%) rotate(3deg);
    }
}

.particle {
    position: absolute;
    bottom: 250px;
    left: 50%;
    width: 4px;
    height: 4px;
    background: radial-gradient(circle,
        rgba(255, 255, 200, 1) 0%,
        rgba(255, 200, 100, 0.9) 30%,
        rgba(255, 150, 50, 0.6) 60%,
        transparent 100%);
    border-radius: 50%;
    animation: emberRise 4s ease-out infinite;
    filter: blur(0.5px);
    mix-blend-mode: screen;
}

.particle:nth-child(4) {
    animation-delay: 0s;
    left: 38%;
    animation-duration: 3.2s;
    width: 3px;
    height: 3px;
}
.particle:nth-child(5) {
    animation-delay: 0.8s;
    left: 62%;
    animation-duration: 3.8s;
    width: 5px;
    height: 5px;
}
.particle:nth-child(6) {
    animation-delay: 1.6s;
    left: 45%;
    animation-duration: 3.5s;
    width: 4px;
    height: 4px;
}
.particle:nth-child(7) {
    animation-delay: 2.4s;
    left: 55%;
    animation-duration: 4s;
    width: 3px;
    height: 3px;
}
.particle:nth-child(8) {
    animation-delay: 0.4s;
    left: 50%;
    animation-duration: 3.6s;
    width: 4px;
    height: 4px;
}
.particle:nth-child(9) {
    animation-delay: 1.2s;
    left: 52%;
    animation-duration: 3.3s;
    width: 3px;
    height: 3px;
}
.particle:nth-child(10) {
    animation-delay: 2s;
    left: 42%;
    animation-duration: 3.7s;
    width: 5px;
    height: 5px;
}
.particle:nth-child(11) {
    animation-delay: 2.8s;
    left: 58%;
    animation-duration: 3.4s;
    width: 4px;
    height: 4px;
}

.fire-glow {
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 450px;
    background:
        radial-gradient(ellipse 60% 50% at 50% 80%,
            rgba(255, 150, 0, 0.6) 0%,
            rgba(255, 100, 0, 0.4) 30%,
            rgba(255, 69, 0, 0.3) 50%,
            transparent 70%);
    animation: fireGlowPulse 1.5s ease-in-out infinite alternate;
    filter: blur(30px);
}

@keyframes fireGlowPulse {
    0% {
        opacity: 0.8;
        transform: translateX(-50%) scale(1);
    }
    100% {
        opacity: 1;
        transform: translateX(-50%) scale(1.15);
    }
}

@keyframes emberRise {
    0% {
        transform: translateY(0) translateX(0) scale(1);
        opacity: 0.9;
    }
    20% {
        opacity: 1;
    }
    50% {
        transform: translateY(-180px) translateX(15px) scale(0.7);
        opacity: 0.7;
    }
    80% {
        opacity: 0.3;
    }
    100% {
        transform: translateY(-350px) translateX(-20px) scale(0.2);
        opacity: 0;
    }
}

/* 弹窗样式 */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(ellipse at center, rgba(20, 10, 40, 0.95) 0%, rgba(0, 0, 0, 0.98) 100%);
    backdrop-filter: blur(10px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    animation: fadeIn 1.5s ease-out;
}

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

.modal-content {
    background: linear-gradient(135deg,
        rgba(45, 10, 78, 0.9) 0%,
        rgba(26, 0, 51, 0.95) 50%,
        rgba(20, 5, 40, 0.9) 100%);
    padding: 60px 80px;
    border-radius: 30px;
    text-align: center;
    box-shadow:
        0 0 60px rgba(255, 105, 180, 0.4),
        0 0 120px rgba(138, 43, 226, 0.3),
        0 20px 80px rgba(0, 0, 0, 0.5),
        inset 0 0 100px rgba(255, 182, 193, 0.05);
    border: 1px solid rgba(255, 182, 193, 0.2);
    animation: modalAppear 1s cubic-bezier(0.34, 1.56, 0.64, 1);
    position: relative;
    overflow: hidden;
}

.modal-content::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle,
        rgba(255, 182, 193, 0.1) 0%,
        transparent 50%);
    animation: modalGlow 4s ease-in-out infinite;
}

@keyframes modalGlow {
    0%, 100% { transform: translate(0, 0) scale(1); opacity: 0.5; }
    50% { transform: translate(10%, 10%) scale(1.1); opacity: 1; }
}

@keyframes modalAppear {
    0% {
        transform: scale(0.3) translateY(-200px) rotate(-10deg);
        opacity: 0;
    }
    70% {
        transform: scale(1.05) translateY(10px) rotate(2deg);
    }
    100% {
        transform: scale(1) translateY(0) rotate(0deg);
        opacity: 1;
    }
}

.modal-content h2 {
    color: #ffb6c1;
    font-size: 38px;
    margin-bottom: 35px;
    text-shadow:
        0 0 30px rgba(255, 182, 193, 0.8),
        0 0 60px rgba(255, 105, 180, 0.5),
        0 5px 15px rgba(0, 0, 0, 0.5);
    font-weight: normal;
    letter-spacing: 5px;
    position: relative;
    z-index: 1;
    animation: titleFloat 3s ease-in-out infinite;
}

@keyframes titleFloat {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

.modal-content p {
    color: #fff;
    font-size: 22px;
    line-height: 2;
    margin-bottom: 45px;
    text-shadow:
        0 0 20px rgba(255, 255, 255, 0.6),
        0 2px 10px rgba(0, 0, 0, 0.5);
    position: relative;
    z-index: 1;
    letter-spacing: 2px;
}

#confirm-btn {
    background: linear-gradient(135deg,
        #ff69b4 0%,
        #ff1493 50%,
        #c71585 100%);
    color: white;
    border: none;
    padding: 18px 60px;
    font-size: 20px;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    box-shadow:
        0 10px 30px rgba(255, 105, 180, 0.5),
        0 0 40px rgba(255, 20, 147, 0.3),
        inset 0 -2px 10px rgba(0, 0, 0, 0.2),
        inset 0 2px 10px rgba(255, 255, 255, 0.2);
    font-family: 'Georgia', serif;
    letter-spacing: 3px;
    position: relative;
    z-index: 1;
    overflow: hidden;
}

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

#confirm-btn:hover::before {
    width: 300px;
    height: 300px;
}

#confirm-btn:hover {
    transform: translateY(-5px) scale(1.05);
    box-shadow:
        0 15px 40px rgba(255, 105, 180, 0.7),
        0 0 60px rgba(255, 20, 147, 0.5),
        inset 0 -2px 10px rgba(0, 0, 0, 0.2),
        inset 0 2px 10px rgba(255, 255, 255, 0.3);
}

#confirm-btn:active {
    transform: translateY(-2px) scale(1.02);
}

/* 便签样式 */
.sticky-note {
    position: fixed;
    width: 280px;
    min-height: 140px;
    padding: 25px;
    background: linear-gradient(135deg, #fff9c4 0%, #fff59d 100%);
    box-shadow:
        0 15px 40px rgba(0, 0, 0, 0.3),
        0 5px 15px rgba(0, 0, 0, 0.2),
        inset 0 0 50px rgba(255, 255, 255, 0.5);
    border-radius: 5px;
    font-size: 17px;
    line-height: 1.8;
    color: #333;
    cursor: move;
    z-index: 100;
    animation: stickyAppear 0.8s cubic-bezier(0.34, 1.56, 0.64, 1);
    font-family: 'KaiTi', '楷体', 'STKaiti', serif;
    word-wrap: break-word;
    word-break: keep-all;
    white-space: normal;
    border: 1px solid rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.sticky-note:hover {
    box-shadow:
        0 20px 50px rgba(0, 0, 0, 0.4),
        0 10px 20px rgba(0, 0, 0, 0.3),
        inset 0 0 50px rgba(255, 255, 255, 0.6);
    transform: translateY(-5px) !important;
}

.sticky-note::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 40px;
    background: linear-gradient(to bottom,
        rgba(0, 0, 0, 0.08) 0%,
        rgba(0, 0, 0, 0.03) 50%,
        transparent 100%);
    border-radius: 5px 5px 0 0;
}

.sticky-note::after {
    content: '';
    position: absolute;
    top: 15px;
    left: 50%;
    transform: translateX(-50%);
    width: 40px;
    height: 6px;
    background: rgba(0, 0, 0, 0.1);
    border-radius: 3px;
}

@keyframes stickyAppear {
    0% {
        opacity: 0;
        transform: scale(0) rotate(-180deg) translateY(-100px);
    }
    60% {
        transform: scale(1.1) rotate(10deg) translateY(0);
    }
    100% {
        opacity: 1;
        transform: scale(1) rotate(0deg) translateY(0);
    }
}

.sticky-note.color1 {
    background: linear-gradient(135deg, #fff9c4 0%, #fff59d 100%);
    color: #5d4e37;
}
.sticky-note.color2 {
    background: linear-gradient(135deg, #ffccbc 0%, #ffab91 100%);
    color: #5d4037;
}
.sticky-note.color3 {
    background: linear-gradient(135deg, #e1bee7 0%, #ce93d8 100%);
    color: #4a148c;
}
.sticky-note.color4 {
    background: linear-gradient(135deg, #c5e1a5 0%, #aed581 100%);
    color: #33691e;
}
.sticky-note.color5 {
    background: linear-gradient(135deg, #b3e5fc 0%, #81d4fa 100%);
    color: #01579b;
}
.sticky-note.color6 {
    background: linear-gradient(135deg, #ffccbc 0%, #ef9a9a 100%);
    color: #b71c1c;
}

/* 响应式设计 - 手机端适配 */
@media (max-width: 768px) {
    /* 信封适配 */
    .envelope {
        width: 280px;
        height: 180px;
    }

    .envelope-text {
        font-size: 16px;
        letter-spacing: 2px;
    }

    .envelope-seal {
        width: 40px;
        height: 40px;
        font-size: 22px;
    }

    /* 信纸适配 */
    .letter-paper {
        width: 90vw;
        max-width: 700px;
        height: auto;
        min-height: 650px;
        max-height: none;
        padding: 50px 40px 45px;
        overflow-y: auto;
    }

    .letter-paper::after {
        font-size: 20px;
        letter-spacing: 15px;
    }

    .letter-content {
        font-size: 15px;
        line-height: 1.9;
        letter-spacing: 1.2px;
    }

    .letter-signature {
        font-size: 19px;
        letter-spacing: 2px;
    }

    .continue-btn {
        padding: 12px 40px;
        font-size: 16px;
    }

    /* 火焰适配 */
    .fire {
        width: 300px;
        height: 300px;
    }

    .fire-main {
        width: 120px;
        height: 250px;
    }

    .fire-main:nth-child(2) {
        width: 150px;
        height: 280px;
    }

    .fire-main:nth-child(3) {
        width: 100px;
        height: 220px;
    }

    .fire-glow {
        width: 400px;
        height: 300px;
    }

    /* 弹窗适配 */
    .modal-content {
        padding: 40px 30px;
        width: 90%;
        max-width: 400px;
    }

    .modal-content h2 {
        font-size: 28px;
        letter-spacing: 3px;
        margin-bottom: 25px;
    }

    .modal-content p {
        font-size: 18px;
        line-height: 1.8;
        margin-bottom: 35px;
    }

    #confirm-btn {
        padding: 15px 45px;
        font-size: 18px;
    }

    /* 便签适配 */
    .sticky-note {
        width: 260px;
        min-height: 120px;
        padding: 20px;
        font-size: 15px;
        line-height: 1.7;
    }
}

@media (max-width: 480px) {
    /* 超小屏幕适配 */
    .envelope {
        width: 240px;
        height: 150px;
    }

    .envelope-text {
        font-size: 14px;
    }

    .letter-paper {
        width: 95vw;
        max-width: 550px;
        height: auto;
        min-height: 80vh;
        max-height: none;
        padding: 40px 30px 35px;
        overflow-y: auto;
    }

    .letter-paper::after {
        font-size: 18px;
        letter-spacing: 10px;
        top: 30px;
    }

    .letter-content {
        font-size: 14px;
        line-height: 1.8;
        letter-spacing: 1px;
    }

    .letter-signature {
        font-size: 17px;
        letter-spacing: 2px;
    }

    .fire {
        width: 250px;
        height: 250px;
    }

    .fire-main {
        width: 100px;
        height: 200px;
    }

    .fire-main:nth-child(2) {
        width: 120px;
        height: 220px;
    }

    .fire-main:nth-child(3) {
        width: 80px;
        height: 180px;
    }

    .modal-content {
        padding: 30px 20px;
    }

    .modal-content h2 {
        font-size: 24px;
        letter-spacing: 2px;
    }

    .modal-content p {
        font-size: 16px;
    }

    #confirm-btn {
        padding: 12px 35px;
        font-size: 16px;
    }

    .sticky-note {
        width: 240px;
        min-height: 100px;
        padding: 18px;
        font-size: 14px;
        line-height: 1.6;
    }
}