/* GIAO DIỆN SOFT BRUTALISM - RANDOM NUMBER */
.tool-container {
    font-family: 'Inter', 'Montserrat', system-ui, -apple-system, sans-serif;
    max-width: 900px;
    margin: 20px auto;
    border: 3px solid #111111;
    border-radius: 12px;
    box-shadow: 6px 6px 0px #111111;
    padding: 30px;
    background: #fff;
    color: #111111;
    box-sizing: border-box;
}

.settings-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 20px;
}

.input-group label, .adv-col label {
    display: block;
    font-weight: 800;
    margin-bottom: 8px;
    font-size: 1.05rem;
}

.input-group input[type="number"], .adv-col select {
    width: 100%;
    padding: 12px;
    font-size: 1.1rem;
    font-weight: bold;
    font-family: inherit;
    border: 3px solid #111111;
    border-radius: 8px;
    outline: none;
    box-sizing: border-box;
    background-color: #f9f9f9;
    box-shadow: 3px 3px 0px #111111;
    transition: transform 0.1s, box-shadow 0.1s;
}

.input-group input[type="number"]:focus, .adv-col select:focus {
    background-color: #fff;
    transform: translate(2px, 2px);
    box-shadow: 1px 1px 0px #111111;
}

.advanced-settings {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 20px;
    background-color: #f4f4f4;
    padding: 20px;
    border: 3px solid #111111;
    border-radius: 8px;
    margin-bottom: 25px;
    align-items: end;
}

/* Custom Checkbox */
.checkbox-container {
    display: flex;
    align-items: center;
    cursor: pointer;
    font-weight: 700;
    font-size: 1.05rem;
    user-select: none;
    height: 48px; /* Căn chỉnh cho bằng với thẻ input */
}
.checkbox-container input {
    margin-right: 10px;
    width: 20px;
    height: 20px;
    accent-color: #111111;
    cursor: pointer;
}

.action-buttons {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 15px;
    margin-bottom: 25px;
}

.action-buttons button {
    cursor: pointer;
    font-size: 1.2rem;
    font-weight: 900;
    padding: 15px;
    border: 3px solid #111111;
    border-radius: 8px;
    box-shadow: 4px 4px 0px #111111;
    transition: transform 0.1s, box-shadow 0.1s;
    text-transform: uppercase;
    color: #111111;
    font-family: inherit;
}
.action-buttons button:active:not(:disabled) {
    transform: translate(4px, 4px);
    box-shadow: 0px 0px 0px #111111;
}
.btn-generate { background-color: #ffdac1; } /* Pastel Orange */
.btn-copy { background-color: #cbaacb; } /* Pastel Purple */
.action-buttons button:disabled {
    background-color: #e0e0e0;
    cursor: not-allowed;
    color: #888;
}

.result-box {
    background-color: #e2f0cb; /* Pastel Yellow-Green */
    border: 3px solid #111111;
    border-radius: 8px;
    padding: 30px;
    text-align: center;
    min-height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: inset 0px 0px 10px rgba(0,0,0,0.05);
}

.number-output {
    font-family: 'Montserrat', 'Inter', system-ui, sans-serif;
    font-weight: 900;
    font-size: 45px;
    color: #111111;
    word-break: break-word;
    line-height: 1.3;
    text-shadow: 2px 2px 0px #fff;
}
.number-output .empty-text {
    font-family: 'Inter', system-ui, sans-serif;
    font-size: 1.2rem;
    color: rgba(17,17,17,0.5);
    text-shadow: none;
    font-weight: 800;
}

.history-box {
    margin-top: 25px;
    padding: 15px;
    background-color: #f9f9f9;
    border: 2px dashed #111111;
    border-radius: 8px;
}
.history-box h4 { margin: 0 0 10px 0; font-size: 1.1rem; }
.history-box ul { list-style: none; padding: 0; margin: 0; }
.history-box li { font-size: 1.05rem; padding: 8px 0; border-bottom: 1px solid #ccc; font-weight: bold; color: #333; }
.history-box li:last-child { border-bottom: none; }

#toastNumber {
    visibility: hidden;
    min-width: 200px;
    background-color: #111111;
    color: #ffffff;
    text-align: center;
    border-radius: 8px;
    padding: 12px;
    position: fixed;
    z-index: 9999;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    font-weight: bold;
    opacity: 0;
    transition: opacity 0.3s, bottom 0.3s;
}
#toastNumber.show {
    visibility: visible;
    opacity: 1;
    bottom: 50px;
}

@media (max-width: 768px) {
    .settings-grid, .advanced-settings { grid-template-columns: 1fr; gap: 15px; }
    .action-buttons { grid-template-columns: 1fr; }
    .number-output { font-size: 35px; }
    .check-col { justify-content: flex-start; }
}