/* CSS 리셋 및 기본 스타일 */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg-color: #f0f2f5;
    --card-bg: #ffffff;
    --text-main: #333;
    --text-heading: #1a1a1a;
    --text-sub: #666;
    --btn-bg: #007bff;
    --btn-hover: #0056b3;
    --btn-text: #ffffff;
    --msg-bg: #e6f4ea;
    --msg-text: #137333;
}

[data-theme="dark"] {
    --bg-color: #121212;
    --card-bg: #1e1e1e;
    --text-main: #e0e0e0;
    --text-heading: #ffffff;
    --text-sub: #b0b0b0;
    --btn-bg: #bb86fc;
    --btn-hover: #9965f4;
    --btn-text: #000000;
    --msg-bg: #2d3e2d;
    --msg-text: #a8d5a8;
}

body {
    font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: var(--text-main);
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* 카드 컨테이너 스타일 */
.card {
    background-color: var(--card-bg);
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05);
    text-align: center;
    max-width: 400px;
    width: 90%;
    transition: transform 0.3s ease, box-shadow 0.3s ease, background-color 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

h1 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--text-heading);
}

p {
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-sub);
    margin-bottom: 1.5rem;
}

/* 버튼 스타일 */
button {
    background-color: var(--btn-bg);
    color: var(--btn-text);
    border: none;
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease;
    width: 100%;
    margin-bottom: 0.5rem;
}

button:hover {
    background-color: var(--btn-hover);
}

button:active {
    transform: scale(0.98);
}

/* 메시지 스타일 */
#message {
    margin-top: 1.5rem;
    margin-bottom: 0;
    padding: 1rem;
    background-color: var(--msg-bg);
    color: var(--msg-text);
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 500;
    transition: opacity 0.5s ease, transform 0.5s ease, background-color 0.3s ease, color 0.3s ease;
}

.hidden {
    display: none;
    opacity: 0;
    transform: translateY(-10px);
}

/* 메시지가 보일 때 애니메이션 효과 */
#message:not(.hidden) {
    display: block;
    animation: fadeIn 0.4s forwards;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}