:root {
    --card-background: white;
    --body-background: #f4f5f7;
    --text-primary: #171717;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --accent-bg: #e6f7ff;
    --accent-text: #0c4a6e;
    --accent-border: #91d5ff;
    --success-flash: #0c4a6e;
}

@media (prefers-color-scheme: dark) {
    :root {
        --card-background: #1e293b;
        --body-background: #0f172a;
        --text-primary: #f1f5f9;
        --text-secondary: #94a3b8;
        --border-color: #334155;
        
        --accent-bg: #334155;
        --accent-text: #cbd5e1;
        --accent-border: #475569;
        --success-flash: #cbd5e1;
    }
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--body-background);
    color: var(--text-primary);
    margin: 0;
    padding: 20px 10px;
    box-sizing: border-box;
}
.main-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
    min-height: 100dvh;
}
.card {
    background-color: var(--card-background);
    padding: 32px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.07);
    text-align: center;
    max-width: 380px;
    width: 100%;
    box-sizing: border-box;
}

@media (prefers-color-scheme: dark) {
    .card {
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
    }
}
h1 { font-size: 26px; margin: 0 0 15px 0; }
.uf-display-box {
    margin-bottom: 25px;
    color: var(--text-primary);
    font-weight: 500;
    font-size: 16px;
}
.uf-display-box .uf-date {
    display: block;
    font-size: 12px;
    font-style: italic;
    color: var(--text-secondary);
    margin-top: 4px;
}
.input-group { text-align: left; margin-bottom: 25px; }
.input-group label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 8px;
    color: var(--text-secondary);
}
.input-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    font-size: 20px;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
    background-color: var(--card-background);
    color: var(--text-primary);
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.input-group input:focus {
    outline: none;
    border-color: var(--accent-border);
    box-shadow: 0 0 0 3px rgba(145, 213, 255, 0.15);
}

@media (prefers-color-scheme: dark) {
    .input-group input:focus {
        box-shadow: 0 0 0 3px rgba(71, 85, 105, 0.4);
    }
}
.result {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: var(--accent-bg);
    border: 1px solid var(--accent-border);
    border-radius: 12px;
    padding: 15px;
    cursor: pointer; 
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}


.result:hover {
    transform: scale(1.0005);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

@media (prefers-color-scheme: dark) {
    .result:hover {
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.6);
    }
}
.result-text { text-align: left; }
.result-text h2 {
    font-size: 16px;
    margin: 0;
    color: var(--accent-text);
    font-weight: 500;
}
.result-text p {
    font-size: 28px;
    font-weight: 700;
    margin: 2px 0 0 0;
    color: var(--accent-text);
}
.copy-feedback {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 45px;
    position: relative;
    min-width: 50px;
    padding: 6px 8px;
}
.copy-icon {
    position: absolute;
    top: 10px;
    left: 50%;
    transform: translateX(-50%);
    width: 18px;
    height: 18px;
    opacity: 0.8;
    transition: opacity 0.2s ease;
}

.result.is-copying .copy-icon {
    opacity: 0.8;
}

.copy-feedback:hover .copy-icon {
    opacity: 1;
}
#icon-copy-wrapper, #icon-check-wrapper {
    position: absolute;
    top: 0;
    left: 0;
    width: 18px;
    height: 18px;
    transition: opacity 0.2s ease;
}
#icon-check-wrapper {
    opacity: 0;
}
.copy-icon svg {
    width: 100%;
    height: 100%;
    color: var(--accent-text);
    display: block;
}
.copy-text {
    font-size: 10px;
    font-weight: 500;
    color: var(--accent-text);
    position: absolute;
    top: 32px;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0;
    transition: opacity 0.2s ease;
    white-space: nowrap;
}
.result.is-copying { animation: flash 0.4s ease-out; }
.result.is-copying .copy-text { opacity: 1; }
.result.is-copying #icon-copy-wrapper { opacity: 0; }
.result.is-copying #icon-check-wrapper { opacity: 1; }
.result.shake { animation: shake 0.3s ease-out; }
@keyframes flash {
    0% { background-color: var(--accent-bg); }
    50% { background-color: var(--success-flash); }
    100% { background-color: var(--accent-bg); }
}
@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-2px); }
    75% { transform: translateX(2px); }
}

@media (prefers-color-scheme: dark) {
    @keyframes flash {
        0% { background-color: var(--accent-bg); }
        50% { background-color: var(--success-flash); }
        100% { background-color: var(--accent-bg); }
    }
}
.credit {
    text-align: center;
    margin-top: 25px;
    color: var(--text-secondary);
    font-size: 12px;
    opacity: 0.8;
}
.credit a {
    color: var(--text-secondary);
    font-weight: 500;
    text-decoration: none;
}
.credit a:hover { text-decoration: underline; }

.data-source {
    text-align: center;
    margin-top: 8px;
    color: var(--text-secondary);
    font-size: 10px;
    opacity: 0.6;
}