/* =========================================
   UI 与导航控件 (navigation.css)
   ========================================= */

.nav-controls {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none; /* 让鼠标事件穿透到下一层(viewport) */
    z-index: 100;
}

.nav-btn {
    pointer-events: auto;
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: transparent;
    border: none;
    width: 60px;
    height: 100px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: opacity 0.24s ease, transform 0.24s ease;
    border-radius: 8px;
    opacity: 0; /* 默认隐藏 */
}

/* 只有鼠标直接移动到控制区域(两侧或者底部)才显示对应按钮块，
   不再是移入整个 presentation 都能看见 */
.nav-btn:hover {
    background: transparent;
    opacity: 1 !important;
}

/* 为触发区域增加不可见的感应辅助(通过伪元素扩大hover区) */
.nav-btn::before {
    content: '';
    position: absolute;
    top: -100px; bottom: -100px; 
    left: -50px; right: -50px;
    /* width: 200px; height: 300px; 扩大触发面积 */
}
.nav-btn:hover {
    opacity: 1;
}
.nav-prev:hover, .nav-next:hover {
    opacity: 1;
}
/* 给一个相对独立的热区捕获 */
.nav-prev-zone, .nav-next-zone {
    pointer-events: auto;
    position: absolute;
    top: 0;
    width: 15%;
    height: 100%;
    z-index: 90;
}
.nav-prev-zone { left: 0; }
.nav-next-zone { right: 0; }

.nav-prev-zone:hover ~ .nav-prev,
.nav-next-zone:hover ~ .nav-next,
.nav-prev:hover,
.nav-next:hover {
    opacity: 1; /* 只有移到边缘15%区域或者按钮身上时才显示 */
    transform: translateY(-50%);
}

.nav-btn svg {
    fill: rgba(128, 128, 128, 0.92);
    width: 40px;
    height: 40px;
}

.nav-prev { left: 20px; z-index: 91; pointer-events: auto; }
.nav-next { right: 20px; z-index: 91; pointer-events: auto; }

/* 底部状态栏 */
.footer-bar-zone {
    pointer-events: auto;
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 80px; /* 增大底部热区 */
    z-index: 90;
}

.footer-bar {
    pointer-events: auto;
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 40px;
    background: rgba(0, 0, 0, 0.6);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    opacity: 0; /* 默认隐藏 */
    transition: opacity 0.3s;
    z-index: 91;
}

.footer-bar-zone:hover ~ .footer-bar,
.footer-bar:hover {
    opacity: 1; /* 鼠标靠底才显示进度条 */
}

.progress-bar-container {
    width: 100%;
    height: 4px;
    background: rgba(255, 255, 255, 0.2);
}

.progress-bar {
    height: 100%;
    background: var(--color-primary);
    width: 0%;
    transition: width 0.3s ease;
}

.status-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    height: 36px;
    color: rgba(255, 255, 255, 0.8);
    font-size: 14px;
}

.fullscreen-btn {
    background: none;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0.7;
    transition: opacity 0.3s;
}

.fullscreen-btn:hover {
    opacity: 1;
}

.fullscreen-btn svg {
    fill: #FFF;
}