:root {
    --primary-blue: #1a73e8;
    --primary-text: #3c4043;
    --secondary-text: #5f6368;
    --error-text: #d93025;
    --background-color: #f0f2f;
    --panel-background: #ffffff;
    --output-panel-background: #f0f0f0;
    --border-color: #dadce0;
    --border-color-active: #1a73e8;
    --hover-background: #f0f2f5; /* Made this slightly darker for better hover on buttons */
    --font-family: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-family), monospace;
    background-color: var(--background-color);
    color: var(--primary-text);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 2rem 1rem;
    min-height: 100vh;
}

.app-container {
    width: 100%;
    max-width: 950px;
    animation: fadeIn 0.5s ease-out;
}

.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding: 0 0.5rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--secondary-text);
}

.github-link {
    color: var(--secondary-text);
    transition: color 0.2s;
}

.github-link:hover {
    color: var(--primary-text);
}

.mode-selector {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 0.5rem;
}

.mode-tabs {
    display: flex;
}

.mode-tab {
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    border: none;
    border-bottom: 3px solid transparent;
    background: none;
    cursor: pointer;
    color: var(--secondary-text);
    transition: color 0.2s;
}

.mode-tab:not([disabled]):hover {
    color: var(--primary-text);
}

.mode-tab.active {
    color: var(--primary-blue);
    border-bottom-color: var(--primary-blue);
}

.mode-tab[disabled] {
    cursor: default;
}

.swap-btn {
    background: none;
    border: none;
    padding: 0.5rem;
    border-radius: 50%;
    cursor: pointer;
    color: var(--secondary-text);
    transition: transform 0.3s, background-color 0.2s;
}

.swap-btn:hover {
    background-color: var(--hover-background);
    transform: rotate(180deg);
}

.panels-container {
    display: flex;
    gap: 1.5rem;
    margin-top: 0.5rem;
}

.panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 300px;
    background-color: var(--panel-background);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    box-shadow: none;
    transition: border-color 0.3s;
}

/* --- NEW --- Set a specific background for the output panel */
.panel-output {
    background-color: var(--output-panel-background);
}

.panel-input.focused {
    border-color: var(--border-color-active);
}

.text-area {
    flex-grow: 1;
    width: 100%;
    padding: 1rem 1.25rem;
    font-family: inherit;
    font-size: 1.25rem;
    border: none;
    resize: none;
    background: none;
    border-radius: 12px 12px 0 0;
}

.text-area:focus {
    outline: none;
}

.text-area::placeholder {
    color: #aab;
}

#output-container, .panel-toolbar {
    padding: 0.5rem 1rem;
}

#output-container {
    position: relative;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.result-box, .error-box {
    opacity: 0;
    animation: resultFadeIn 0.4s forwards;
    padding-top: 0.5rem;
}

.result-box {
    color: var(--primary-text);
    font-weight: 400;
    font-size: 1.5rem;
    word-break: break-all;
}

.error-box {
    color: var(--error-text);
    font-size: 0.9rem;
}

.empty-state {
    position: absolute;
    top: 1rem;
    left: 1.25rem;
    color: var(--secondary-text);
    font-size: 1.5rem;
    transition: opacity 0.3s;
}

.input-has-text .empty-state {
    opacity: 0;
    visibility: hidden;
}

.panel-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid #e8eaed;
    min-height: 48px;
}

.char-count {
    font-size: 0.75rem;
    color: var(--secondary-text);
}

.icon-btn {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--secondary-text);
    padding: 0.5rem;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: background-color 0.2s;
}

.icon-btn:hover {
    background-color: var(--hover-background);
}

.info-container {
    position: relative;
    display: flex;
    align-items: center;
}

.info-icon {
    color: var(--secondary-text);
    cursor: pointer;
}

.info-tooltip {
    visibility: hidden;
    opacity: 0;
    background-color: var(--primary-text);
    color: #fff;
    text-align: center;
    border-radius: 6px;
    padding: 8px 12px;
    position: absolute;
    z-index: 10;
    bottom: 150%;
    left: 50%;
    transform: translateX(-50%);
    width: 220px;
    font-size: 0.8rem;
    line-height: 1.4;
    transition: opacity 0.3s, visibility 0.3s;
}

.info-container:hover .info-tooltip {
    visibility: visible;
    opacity: 1;
}

.copy-tooltip {
    visibility: hidden;
    background-color: var(--primary-text);
    color: #fff;
    text-align: center;
    border-radius: 4px;
    padding: 5px 10px;
    position: absolute;
    z-index: 1;
    bottom: 125%;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0;
    transition: opacity 0.3s;
    font-size: 0.8rem;
    white-space: nowrap;
}

.copy-btn.copied .copy-tooltip {
    visibility: visible;
    opacity: 1;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes resultFadeIn {
    from {
        opacity: 0;
        transform: translateY(5px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 768px) {
    body {
        padding: 1rem;
    }

    .panels-container {
        flex-direction: column;
    }

    .mode-selector {
        flex-wrap: wrap;
        justify-content: center;
    }
}