:root { 
    --main-red: #FF0000; 
    --bg-gray: #F2F4F7; 
    --dark: #202124; 
    --shadow: 0 4px 15px rgba(0,0,0,0.08); 
}

* { box-sizing: border-box; }

body { 
    font-family: 'Noto Sans KR', sans-serif; 
    background: var(--bg-gray); 
    margin: 0; 
    line-height: 1.8; 
    overflow-x: hidden; 
}

/* Navigation Bar */
nav { 
    background: #fff; 
    padding: 15px 8%; 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    border-bottom: 1px solid #eee; 
    position: sticky; 
    top: 0; 
    z-index: 1000; 
}

.logo { 
    font-size: 1.3rem; 
    font-weight: bold; 
    color: var(--main-red); 
    text-decoration: none; 
}

.nav-links a { 
    margin-left: 15px; 
    text-decoration: none; 
    color: #555; 
    font-size: 0.9rem; 
    font-weight: 500; 
}

.nav-links a:hover { color: var(--main-red); }

/* Layout Containers */
.container { 
    max-width: 1000px; 
    margin: 30px auto; 
    padding: 0 15px; 
}

.card { 
    background: #fff; 
    padding: 30px; 
    border-radius: 16px; 
    box-shadow: var(--shadow); 
    margin-bottom: 25px; 
    text-align: center; 
}

/* Input Elements */
.input-group { 
    max-width: 650px; 
    margin: 25px auto; 
    display: flex; 
    flex-direction: column; 
    gap: 10px; 
}

input { 
    width: 100%; 
    border: 1.5px solid #ddd; 
    padding: 15px; 
    border-radius: 12px; 
    font-size: 1rem; 
    outline: none; 
}

input:focus { border-color: var(--main-red); }

button { 
    width: 100%; 
    background: var(--main-red); 
    color: #fff; 
    border: none; 
    padding: 15px; 
    border-radius: 12px; 
    cursor: pointer; 
    font-weight: bold; 
    font-size: 1.1rem; 
}

button:hover { background: #cc0000; }

/* Stats Display */
.stats-grid { 
    display: grid; 
    grid-template-columns: 1fr; 
    gap: 15px; 
    margin-top: 25px; 
    display: none; /* JS에서 결과가 나올 때 grid로 변경됨 */
}

.stat-item { 
    background: #fff; 
    padding: 25px; 
    border-radius: 12px; 
    border: 1px solid #eee; 
}

.stat-value { 
    font-size: 1.6rem; 
    font-weight: bold; 
    color: var(--main-red); 
}

/* Rich Text & Table Optimization for AdSense */
.rich-text { 
    text-align: left; 
    color: #5F6368; 
    font-size: 0.95rem; 
}

.rich-text h2 { 
    color: var(--dark); 
    border-left: 5px solid var(--main-red); 
    padding-left: 12px; 
    margin: 35px 0 15px; 
}

.rich-text table { 
    width: 100%; 
    border-collapse: collapse; 
    margin: 25px 0; 
    background: #fff; 
}

.rich-text th, .rich-text td { 
    padding: 12px; 
    border: 1px solid #eee; 
    text-align: left; 
}

.rich-text th { 
    background: #fcfcfc; 
    color: var(--main-red); 
}

.rich-text ul { padding-left: 20px; }

/* Desktop & Tablet Optimization */
@media (min-width: 768px) {
    .input-group { 
        flex-direction: row; 
        gap: 0; 
        border-radius: 50px; 
        overflow: hidden; 
        border: 1px solid #ddd; 
    }
    input { border: none; border-radius: 0; }
    button { width: 160px; border-radius: 0; }
    .stats-grid { grid-template-columns: repeat(3, 1fr); }
}

/* Mobile Optimization for Navigation Bar */
@media (max-width: 600px) {
    nav {
        padding: 10px 5%; 
        flex-direction: column; 
        gap: 10px;
    }

    .logo { font-size: 1.2rem; }

    .nav-links {
        width: 100%;
        display: flex;
        justify-content: space-between; 
        margin: 0;
        padding: 5px 0;
    }

    .nav-links a {
        margin: 0; 
        font-size: 0.85rem; 
        flex: 1; 
        text-align: center;
    }
}