:root {
    --bg-color: #f5f5f5;
    --surface-color: #ffffff;
    --surface-hover: #f9f9f9;
    --text-main: #333333;
    --text-muted: #888888;
    --border-color: #e0e0e0;
    --primary-color: #06C755; /* LINE Green */
    --header-bg: rgba(255, 255, 255, 0.9);
    --bubble-sent: #e0e0e0;
    --bubble-recv: #ffffff;
    --bubble-border: #e0e0e0;
    --delete-bg: #ff3b30;
    --active-highlight: #ffe0b2;
    --highlight-border: #ff9800;
}

[data-theme="dark"] {
    --bg-color: #121212;
    --surface-color: #1e1e1e;
    --surface-hover: #2a2a2a;
    --text-main: #e0e0e0;
    --text-muted: #aaaaaa;
    --border-color: #333333;
    --primary-color: #888888;
    --header-bg: rgba(30, 30, 30, 0.9);
    --bubble-sent: #3a3a3a;
    --bubble-recv: #2a2a2a;
    --bubble-border: #333333;
    --active-highlight: #5c4000;
    --highlight-border: #ffb74d;
}

[data-theme="line"] {
    --bg-color: #8ca9d3;
    --surface-color: #ffffff;
    --surface-hover: #f0f0f0;
    --text-main: #000000;
    --text-muted: #666666;
    --border-color: #e0e0e0;
    --primary-color: #06C755;
    --header-bg: rgba(255, 255, 255, 0.9);
    --bubble-sent: #85e249;
    --bubble-recv: #ffffff;
    --bubble-border: transparent;
    --active-highlight: #ffe0b2;
    --highlight-border: #ff9800;
}

[data-theme="pop"] {
    --bg-color: #f4ebfa;
    --surface-color: #ffffff;
    --surface-hover: #f9f0ff;
    --text-main: #4a3b52;
    --text-muted: #9c8a9e;
    --border-color: #e5d5ec;
    --primary-color: #7b2cbf;
    --header-bg: rgba(255, 255, 255, 0.95);
    --bubble-sent: #9d4edd;
    --bubble-recv: #e9d5ff; /* More distinct purple */
    --bubble-border: transparent;
    --active-highlight: #ffcce6;
    --highlight-border: #ff66b2;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]):not([data-theme="line"]):not([data-theme="pop"]) {
        --bg-color: #121212;
        --surface-color: #1e1e1e;
        --surface-hover: #2a2a2a;
        --text-main: #e0e0e0;
        --text-muted: #aaaaaa;
        --border-color: #333333;
        --primary-color: #888888;
        --header-bg: rgba(30, 30, 30, 0.9);
        --bubble-sent: #3a3a3a;
        --bubble-recv: #2a2a2a;
        --bubble-border: #333333;
        --active-highlight: #5c4000;
        --highlight-border: #ffb74d;
    }
}