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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
    max-width: 500px;
    width: 100%;
    transform: translateY(0);
    transition: all 0.3s ease;
    border: 1px solid #e2e8f0;
}

.container:hover {
    transform: translateY(-2px);
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    color: #2d3748;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 30px;
    position: relative;
}

h1::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, #4299e1, #3182ce);
    border-radius: 2px;
}

.prev_edge {
    background: #f4f4f4;
    padding: 1em;
    border-radius: 8px;
}

.submit-btn {
    width: 100%;
    padding: 16px;
    background: linear-gradient(135deg, #4299e1 0%, #3182ce 100%);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.submit-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(66, 153, 225, 0.3);
}

.submit-btn:hover::before {
    left: 100%;
}

.submit-btn:active {
    transform: translateY(0);
}

.icon {
    display: inline-block;
    margin-right: 8px;
    font-size: 1.2rem;
}

/* 반응형 디자인 */
@media (max-width: 600px) {
    .container {
        padding: 30px 20px;
        margin: 10px;
    }

    h1 {
        font-size: 2rem;
    }

    input[type="text"], .submit-btn {
        padding: 12px 16px;
    }
}

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

.container {
    animation: fadeInUp 0.6s ease-out;
}

/* 로딩 상태 */
.submit-btn:disabled {
    background: #a0aec0;
    cursor: not-allowed;
    transform: none;
}

.submit-btn:disabled:hover {
    transform: none;
    box-shadow: none;
}