body {
    margin: 0;
    font-family: 'Segoe UI', Roboto, sans-serif;
    background: #121212;
    color: #e0e0e0;
    line-height: 1.6;
}

.container {
    max-width: 960px;
    margin: auto;
    padding: 20px;
}

.controls {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
}

.requirement-group {
    border: 1px solid #444;
    border-radius: 6px;
    padding: 12px;
    margin-bottom: 12px;
}

.group-header {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 8px;
}

.alternatives-list {
    margin-bottom: 8px;
}

.alt-item {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 6px;
}

.range-inputs {
    display: flex;
    gap: 12px;
    align-items: center;
    margin-bottom: 8px;
}

.summary-text {
    background: #1e1e1e;
    padding: 12px;
    border-radius: 6px;
    margin-top: 16px;
}

button,
.button-like {
    padding: 10px 16px;
    border: none;
    border-radius: 8px;
    background: #2a2a2a;
    color: #fff;
    cursor: pointer;
    font-size: 0.95em;
    font-family: inherit;
    line-height: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.4);
    transition: all 0.2s ease;
    user-select: none;
}

button:hover,
.button-like:hover {
    background: #444;
}

input[type="number"],
input[type="text"],
select {
    background: #1e1e1e;
    color: #e0e0e0;
    padding: 6px 8px;
    border: 1px solid #444;
    border-radius: 6px;
    font-size: 0.9em;
}

datalist option {
    background: #1e1e1e;
    color: #e0e0e0;
}

.warning {
    color: #ffcc00;
    margin-left: 8px;
    font-weight: bold;
    font-size: 0.9em;
}

.hidden {
    display: none !important;
}

.alt-value.invalid {
    border: 2px solid #ff5252 !important;
}

.tabs {
    display: flex;
    gap: 12px;
    padding: 16px 20px;
    background: #1c1c1c;
    border-bottom: 1px solid #333;
}

.tab-button {
    background: none;
    border: none;
    color: #ccc;
    padding: 10px 16px;
    cursor: pointer;
    font-size: 1em;
    border-radius: 6px;
    transition: background 0.2s, color 0.2s;
}

.tab-button:hover {
    background: #2a2a2a;
    color: #fff;
}

.tab-button.active {
    background: #2f2f2f;
    color: #fff;
    font-weight: bold;
}

.alt-value.invalid,
.card-name.invalid {
    border: 2px solid #ff5252 !important;
}