/* ===== 主题变量 ===== */
/* 默认：墨绿科研 */
:root,
.theme-green {
    --color-surface: #1a2e24;
    --color-primary: #007a5c;
    --color-focus-ring: rgba(0, 122, 92, 0.12);
    --bg-overlay-from: rgba(26, 46, 36, 0.4);
    --bg-overlay-to: rgba(20, 36, 28, 0.3);
    --bg-image: url("../image/bio-link-login-background.jpg");
}

.theme-copper {
    --color-surface: #3a322a;
    --color-primary: #b8956a;
    --color-focus-ring: rgba(184, 149, 106, 0.12);
    --bg-overlay-from: rgba(58, 50, 42, 0.5);
    --bg-overlay-to: rgba(38, 34, 30, 0.4);
    --bg-image: url("../image/bio-link-login-background2.jpg");
}

/* ===== 主题切换器 ===== */
.theme-switcher {
    position: relative;
    display: flex;
    align-items: center;
}

.theme-trigger {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: 6px;
    background: transparent;
    cursor: pointer;
    color: rgba(255, 255, 255, 0.7);
    font-size: 16px;
    transition: all 0.2s;
}

.theme-trigger:hover {
    background: rgba(255, 255, 255, 0.1);
    color: #fff;
}

.theme-panel {
    display: flex;
    align-items: center;
    gap: 8px;
    overflow: hidden;
    transition: all 0.3s ease;
    max-width: 0;
    opacity: 0;
    margin-right: 0;
}

.theme-panel.open {
    max-width: 180px;
    opacity: 1;
    margin-right: 12px;
}

.theme-option {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: 2px solid rgba(255, 255, 255, 0.3);
    cursor: pointer;
    transition: all 0.2s;
    flex-shrink: 0;
    box-sizing: border-box;
}

.theme-option:hover {
    transform: scale(1.2);
    border-color: #fff;
}

.theme-option.active {
    border-color: #fff;
    box-shadow: 0 0 0 2px var(--color-primary);
}