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

body {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(to bottom, #87CEEB, #E0F7FA);
    font-family: "Microsoft YaHei", sans-serif;
    overflow: hidden;
}

.container {
    width: 100%;
    max-width: 800px;
    padding: 20px;
    position: relative;
    z-index: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
}

.cloud {
    position: relative;
    width: 600px;
    height: 350px;
    margin: 0 auto;
    margin-top: 40px;
    transform: scale(0.2);
    opacity: 0;
    animation: cloudEntrance 3s ease-out forwards,
               cloudFloat 3s ease-in-out infinite;
}

.cloud-circle {
    position: absolute;
    background: #FFFFFF;
    border-radius: 50%;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

.circle1 {
    width: 200px;
    height: 200px;
    top: 50px;
    left: 80px;
}

.circle2 {
    width: 180px;
    height: 180px;
    top: 30px;
    left: 220px;
}

.circle3 {
    width: 190px;
    height: 190px;
    top: 60px;
    left: 340px;
}

.circle4 {
    width: 160px;
    height: 160px;
    top: 120px;
    left: 40px;
}

.circle5 {
    width: 140px;
    height: 140px;
    top: 40px;
    left: 400px;
}

.circle6 {
    width: 170px;
    height: 170px;
    top: 90px;
    left: 260px;
}

.circle7 {
    width: 130px;
    height: 130px;
    top: 140px;
    left: 180px;
}

.message {
    color: #333333;
    font-size: 28px;
    font-weight: bold;
    text-align: center;
    width: 100%;
    margin-top: 8vh;
    margin-bottom: auto;
    opacity: 0;
    animation: fadeInUp 1.2s ease-out 0.3s forwards;
}

.input-section {
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-top: auto;
    margin-bottom: 12vh;
    opacity: 0;
    animation: fadeInUp 1.2s ease-out 1.1s forwards;
}

.message-input {
    width: 60%;
    height: 40px;
    padding: 0 15px;
    border: none;
    border-radius: 20px;
    background: rgba(255, 255, 255, 0.7);
    font-size: 16px;
    outline: none;
    transition: box-shadow 0.3s ease;
}

.message-input:focus {
    box-shadow: 0 0 10px rgba(79, 195, 247, 0.5);
}

.submit-btn {
    display: block;
    margin: 20px auto;
    padding: 10px 30px;
    border: none;
    border-radius: 8px;
    background: #4FC3F7;
    color: white;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.submit-btn:hover {
    background: #29B6F6;
    transform: scale(1.05);
}

.particles {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

@keyframes cloudEntrance {
    0% {
        transform: scale(0.2);
        opacity: 0;
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

@keyframes messageAppear {
    0% {
        opacity: 0;
        transform: translate(-50%, -50%) scale(0.9);
    }
    100% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }
}

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

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

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

@media (max-width: 768px) {
    body {
        background:
            linear-gradient(rgba(0,0,0,0.35), rgba(0,0,0,0.35)),
            url('bg-mobile.jpg') no-repeat center center fixed;
        background-size: cover;
    }
    .container {
        min-height: 100vh;
        padding-top: 0;
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
    }
    .cloud {
        width: 320px;
        height: 200px;
        margin-top: 0;
        margin-left: 0;
        display: flex;
        align-items: center;
        justify-content: center;
    }
    .message {
        font-size: 20px;
        margin-top: 5vh;
    }
    .input-section {
        margin-bottom: 8vh;
    }
    .input-section form {
        display: flex !important;
        flex-direction: column !important;
        align-items: center !important;
        width: 100% !important;
    }
    .input-section form .message-input,
    .input-section form input[type="text"] {
        width: 90% !important;
        min-width: 0 !important;
        margin-bottom: 16px !important;
        box-sizing: border-box !important;
        font-size: 18px !important;
        height: 48px !important;
        display: block !important;
    }
    .input-section form .submit-btn,
    .input-section form button[type="submit"] {
        width: 95% !important;
        min-width: 0 !important;
        height: 60px !important;
        font-size: 26px !important;
        margin: 0 !important;
        display: block !important;
        border-radius: 32px !important;
    }
}