* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 2rem 1rem 4rem;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
    color: #222;
    background: #fafafa;
}

header {
    max-width: 640px;
    margin: 0 auto 2rem;
    text-align: center;
}

h1 {
    margin: 0 0 0.25rem;
    font-size: 1.6rem;
}

.subtitle {
    margin: 0 0 1.25rem;
    color: #666;
    font-size: 0.95rem;
}

#search {
    width: 100%;
    padding: 0.65rem 0.9rem;
    font-size: 1rem;
    border: 1px solid #ddd;
    border-radius: 8px;
    outline: none;
}

#search:focus {
    border-color: #999;
}

main {
    max-width: 640px;
    margin: 0 auto;
}

.letter {
    margin: 1.5rem 0 0.5rem;
    font-size: 0.85rem;
    font-weight: 700;
    color: #999;
    letter-spacing: 0.05em;
}

.word {
    background: #fff;
    border: 1px solid #eee;
    border-radius: 8px;
    padding: 0.8rem 1rem;
    margin-bottom: 0.6rem;
}

.word-title {
    font-weight: 600;
    font-size: 1.05rem;
}

.word-category {
    font-size: 0.8rem;
    color: #888;
    margin-left: 0.4rem;
}

.word-definition {
    margin: 0.3rem 0 0;
    color: #444;
    font-size: 0.95rem;
    line-height: 1.4;
}

.empty {
    text-align: center;
    color: #888;
    margin-top: 2rem;
}