.base64-tool {
    max-width: 1000px;
    margin: 0 auto;
}

.base64-card {
    padding: 48px;
    background: linear-gradient(135deg, rgba(254, 119, 67, 0.02) 0%, rgba(68, 125, 155, 0.02) 100%);
}

.mode-selection {
    display: flex;
    gap: 12px;
    justify-content: center;
    margin-bottom: 32px;
    flex-wrap: wrap;
}

.mode-btn {
    padding: 14px 28px;
    border: 2px solid var(--border);
    border-radius: 12px;
    background: var(--surface);
    color: var(--text);
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition-fast);
    display: inline-flex;
    align-items: center;
}

.mode-btn:hover {
    border-color: var(--primary);
    background: rgba(254, 119, 67, 0.05);
    transform: translateY(-1px);
}

.mode-btn.active {
    border-color: var(--primary);
    background: rgba(254, 119, 67, 0.1);
    color: var(--primary);
}

.mode-btn.switch-btn {
    background: var(--navy);
    color: white;
    border-color: var(--navy);
}

.mode-btn.switch-btn:hover {
    background: var(--blue);
    border-color: var(--blue);
}

.mode-btn svg {
    width: 16px;
    height: 16px;
}

.input-section,
.output-section {
    margin-bottom: 24px;
}

.input-label,
.output-label {
    display: block;
    margin-bottom: 12px;
    font-weight: 700;
    color: var(--navy);
    font-size: 16px;
}

.base64-input,
.base64-output {
    width: 100%;
    min-height: 200px;
    padding: 20px;
    font-size: 15px;
    resize: vertical;
    line-height: 1.8;
    font-family: 'Courier New', monospace;
    border: 2px solid var(--border);
    border-radius: 12px;
    background: white;
    color: var(--text);
    transition: var(--transition-fast);
}

.base64-input:focus {
    outline: none;
    border-color: var(--primary);
    background: rgba(254, 119, 67, 0.02);
    box-shadow: 0 0 0 4px rgba(254, 119, 67, 0.1);
}

.base64-output {
    background: var(--surface);
    color: var(--text-soft);
    cursor: default;
}

.base64-output:focus {
    border-color: var(--border);
    box-shadow: none;
}

.input-controls,
.output-controls {
    display: flex;
    gap: 12px;
    margin-top: 12px;
    flex-wrap: wrap;
}

.control-btn {
    padding: 10px 20px;
    background: var(--surface);
    color: var(--text);
    border: 2px solid var(--border);
    border-radius: 8px;
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition-fast);
    display: inline-flex;
    align-items: center;
}

.control-btn:hover {
    border-color: var(--primary);
    background: rgba(254, 119, 67, 0.05);
    transform: translateY(-1px);
}

.control-btn.primary {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.control-btn.primary:hover {
    background: #e65a2e;
    border-color: #e65a2e;
}

.control-btn svg {
    width: 16px;
    height: 16px;
}

@media (max-width: 768px) {
    .base64-tool {
        max-width: 100%;
    }

    .mode-selection {
        flex-direction: column;
    }

    .mode-btn {
        width: 100%;
        justify-content: center;
    }

    .base64-input,
    .base64-output {
        min-height: 150px;
        padding: 16px;
        font-size: 14px;
    }

    .input-controls,
    .output-controls {
        flex-direction: column;
    }

    .control-btn {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .base64-card {
        padding: 32px 24px;
    }

    .base64-input,
    .base64-output {
        min-height: 120px;
        font-size: 13px;
    }
}