:root {
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

*, *::before, *::after {
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
    outline: none;
}

html, body {
    overscroll-behavior-y: auto;
}

html.light {
    --primary: #78a9cc;
    --primary-text: #ffffff;
    --text: #5a6d7d;
    --card: #ffffff;
    --bg: #ebf1f5;
    --input-bg: #f5f9fc;
    --border: #cedde8;
    --shadow: rgba(120, 169, 204, 0.15);
    --link: #5c93bb;
    background: var(--bg);
    color-scheme: light;
}

html.dark {
    --primary: #5c93bb;
    --primary-text: #e0f0fa;
    --text: #b0c4d1;
    --card: #1e2630;
    --bg: #12181f;
    --input-bg: #12181f;
    --border: #323f4d;
    --shadow: rgba(0, 0, 0, 0.5);
    --link: #88b4d4;
    background: var(--bg);
    color-scheme: dark;
}

body {
    font-family: 'M PLUS Rounded 1c', sans-serif;
    margin: 0;
    padding: 15px;
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: var(--text);
    line-height: 1.6;
}

header {
    width: 100%;
    text-align: center;
    margin-bottom: 25px;
}

h1 {
    font-size: 1.5rem;
    font-weight: 900;
    color: var(--primary);
    margin: 10px 0;
    letter-spacing: 0.05em;
}

.mode-select-container {
    display: flex;
    justify-content: center;
    margin-bottom: 25px;
}

select {
    padding: 12px 20px;
    border-radius: 50px;
    border: 2px solid var(--border);
    background: var(--card);
    color: var(--text);
    font-weight: 700;
    font-family: inherit;
    cursor: pointer;
    box-shadow: 0 4px 12px var(--shadow);
    transition: var(--transition);
    appearance: none;
    background-repeat: no-repeat;
    background-position: right 15px center;
    background-size: 10px;
    padding-right: 45px;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3Csvg width='14' height='8' viewBox='0 0 14 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1L7 7L13 1' stroke='%2378a9cc' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
}

.tab-nav {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.tab-nav button {
    flex: 1;
    padding: 15px 10px;
    border-radius: 20px;
    border: 2px solid var(--border);
    background: var(--card);
    color: var(--text);
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 5px 0 var(--border);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.tab-nav button.active {
    background: var(--primary);
    color: var(--primary-text);
    border-color: var(--primary);
    box-shadow: 0 0px 0 var(--primary);
    transform: translateY(5px);
}

main {
    width: 100%;
    background: var(--card);
    border-radius: 35px;
    padding: 30px 20px;
    border: 1px solid var(--border);
    box-shadow: 0 20px 40px var(--shadow);
}

.input-section {
    margin-bottom: 30px;
}

.label-box {
    text-align: center;
    margin-bottom: 12px;
}

.label-main {
    font-weight: 900;
    font-size: 1.1rem;
    color: var(--primary);
    display: block;
}

.label-sub {
    font-size: 0.7rem;
    opacity: 0.6;
    text-transform: uppercase;
}

input {
    width: 100%;
    padding: 20px;
    font-size: 1.8rem;
    border-radius: 25px;
    border: 3px solid var(--border);
    background: var(--input-bg);
    color: var(--text);
    font-family: 'Roboto Mono', monospace;
    text-align: center;
    transition: var(--transition);
}

input:focus {
    border-color: var(--primary);
    background: var(--card);
    box-shadow: 0 0 0 8px var(--shadow);
}

.result-section {
    background: var(--bg);
    border-radius: 30px;
    border: 2px dashed var(--border);
    padding: 25px 15px;
    text-align: center;
    min-height: 140px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.result-label .label-main {
    font-size: 0.85rem;
    opacity: 0.8;
}

.label-hiragana {
    display: block;
    font-size: 0.75rem;
    font-weight: 700;
    opacity: 0.8;
    margin-top: 1px;
    margin-bottom: 1px;
}

.header-hiragana {
    font-size: 0.85rem;
    font-weight: 700;
    opacity: 0.8;
    margin-top: -4px;
}

.header-sub {
    font-size: 0.75rem;
    font-weight: 500;
    opacity: 0.6;
    margin-top: 2px;
}

.tab-hiragana {
    font-size: 0.75rem;
    font-weight: 700;
    opacity: 0.85;
}

#panelDec {
    display: none;
}

.result-value {
    font-size: 2rem;
    font-weight: 900;
    color: var(--primary);
    word-break: break-all;
    overflow-y: auto;
    max-height: 180px;
    padding: 5px;
}

footer {
    width: 100%;
    padding: 25px 0;
    text-align: center;
}

.footer-copy {
    font-weight: 700;
    font-size: 0.75rem;
    letter-spacing: 0.02em;
    color: var(--text);
    opacity: 0.9;
}

a {
    color: var(--link);
    text-decoration: none;
}

@media (max-width: 480px) {
    body { padding: 10px; }
    h1 { font-size: 1.3rem; margin: 5px 0; }
    main { padding: 25px 15px; border-radius: 25px; }
    input { font-size: 1.6rem; padding: 15px; }
    input:focus { box-shadow: 0 0 0 5px var(--shadow); }
    .result-value { font-size: 1.7rem; }
    .tab-nav button { padding: 12px 5px; font-size: 0.85rem; }
}