/* CSS SOFT BRUTALISM */
:root {
    --box-bg: #ffffff;
    --border-color: #111111;
    --shadow-color: #111111;
    --btn-encode: #b5ead7;
    --btn-decode: #ffb7b2;
    --btn-copy: #ffdac1;
    --btn-clear: #e2f0cb;
    
    --border-width: 3px;
    --border-radius: 12px;
    --shadow-offset: 6px;
}

.tool-container {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--box-bg);
    width: 100%;
    max-width: 800px;
    margin: 20px auto; /* Tự động căn giữa khung */
    border: var(--border-width) solid var(--border-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-offset) var(--shadow-offset) 0px var(--shadow-color);
    padding: 30px;
    color: var(--border-color);
    box-sizing: border-box;
}

.tool-container h1 {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 800;
    margin-top: 0;
}

.tool-container .input-group {
    margin-bottom: 20px;
}

.tool-container label {
    display: block;
    font-weight: 700;
    margin-bottom: 8px;
    font-size: 1.1rem;
}

.tool-container textarea {
    width: 100%;
    min-height: 150px;
    padding: 15px;
    font-size: 1rem;
    font-family: 'Courier New', Courier, monospace;
    background-color: #f4f4f4;
    border: var(--border-width) solid var(--border-color);
    border-radius: 8px;
    resize: vertical;
    outline: none;
    transition: all 0.2s ease;
    box-sizing: border-box;
}

.tool-container textarea:focus {
    background-color: #fff;
    box-shadow: 4px 4px 0px var(--shadow-color);
}

.tool-container .action-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.tool-container button {
    cursor: pointer;
    font-size: 1rem;
    font-weight: 700;
    padding: 12px 20px;
    border: var(--border-width) solid var(--border-color);
    border-radius: 8px;
    box-shadow: 4px 4px 0px var(--shadow-color);
    transition: transform 0.1s, box-shadow 0.1s;
    text-transform: uppercase;
    color: var(--border-color);
}

.tool-container button:active {
    transform: translate(4px, 4px);
    box-shadow: 0px 0px 0px var(--shadow-color);
}

.tool-container .btn-encode { background-color: var(--btn-encode); }
.tool-container .btn-decode { background-color: var(--btn-decode); }
.tool-container .btn-copy { background-color: var(--btn-copy); }
.tool-container .btn-clear { background-color: var(--btn-clear); }

.tool-container .btn-fallback {
    width: 100%;
    background-color: #ddd;
    margin-top: 10px;
}

/* Notification Toast */
#toast {
    visibility: hidden;
    min-width: 200px;
    background-color: var(--border-color);
    color: #fff;
    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;
}

#toast.show {
    visibility: visible;
    opacity: 1;
    bottom: 50px;
}

/* Mobile Optimization */
@media (max-width: 600px) {
    .tool-container {
        padding: 20px;
        box-shadow: 4px 4px 0px var(--shadow-color);
    }
    .tool-container textarea {
        min-height: 120px;
    }
    .tool-container .action-buttons {
        grid-template-columns: 1fr 1fr;
    }
}