/* __V3D_TEMPLATE__ - template-based file; delete this line to prevent this file from being updated */

/**
 * 柔和「云朵」过渡背景：略深于亮白的粉彩底 + 左上暖桃 / 右上天蓝 / 下方淡紫，适合儿童课件。
 * 画布若全屏遮盖则主要在外沿、留白与底部 UI 区域可见。
 */
html,
body {
    margin: 0;
    min-height: 100%;
    overflow: hidden;
    background-color: #c9cfe0;
    background-image:
        radial-gradient(ellipse 72% 58% at 8% 6%, rgba(255, 192, 175, 0.72) 0%, transparent 58%),
        radial-gradient(ellipse 68% 52% at 94% 10%, rgba(130, 200, 255, 0.62) 0%, transparent 55%),
        radial-gradient(ellipse 65% 48% at 52% 98%, rgba(232, 195, 238, 0.55) 0%, transparent 52%),
        radial-gradient(ellipse 85% 70% at 48% 45%, rgba(195, 205, 235, 0.55) 0%, transparent 65%),
        linear-gradient(180deg, #d8ddf0 0%, #cfd5e8 45%, #c5cce3 100%);
    background-attachment: fixed;
}

noscript {
    display: block;
    text-align: center;
    padding-top: 100px;
    font-size: 20px;
}

.v3d-container {
    position: absolute;
    top: 0px;
    left: 0px;
    width: 100%;
    height: 100%;
}

.fullscreen-button {
    position: absolute;
    top: 5px;
    right: 5px;
    width: 50px;
    height: 50px;
    cursor: pointer;
    background-size: 100% 100%;
    display: none;
    z-index: 1;
}

.fullscreen-open {
    background-image: url('media/fullscreen_open.svg');
}

.fullscreen-close {
    background-image: url('media/fullscreen_close.svg');
}

.lesson-ui {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 5;
    pointer-events: none;
    display: flex;
    justify-content: center;
    padding: 12px 16px 16px;
    box-sizing: border-box;
    background: linear-gradient(
        to top,
        rgba(232, 228, 250, 0.94) 0%,
        rgba(218, 224, 244, 0.82) 55%,
        rgba(200, 210, 235, 0.35) 88%,
        transparent 100%
    );
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.48s ease, visibility 0.48s ease;
}

.lesson-ui.lesson-ui--ready {
    opacity: 1;
    visibility: visible;
}

.lesson-ui-inner {
    pointer-events: auto;
    max-width: 920px;
    width: 100%;
    font-family: system-ui, "Segoe UI", "Microsoft YaHei", sans-serif;
    position: relative;
}

.lesson-hints {
    max-height: 200px;
    margin-bottom: 12px;
    padding: 10px 12px;
    border-radius: 10px;
    background: rgba(255, 250, 252, 0.78);
    border: 1px solid rgba(255, 255, 255, 0.65);
    box-shadow: 0 2px 12px rgba(120, 130, 180, 0.12);
    overflow: hidden;
    transition:
        opacity 0.55s ease,
        max-height 0.55s ease,
        margin 0.55s ease,
        padding 0.55s ease,
        border-width 0.55s ease,
        box-shadow 0.55s ease;
}

.lesson-hints.lesson-hints--gone {
    max-height: 0;
    margin-bottom: 0;
    padding-top: 0;
    padding-bottom: 0;
    padding-left: 12px;
    padding-right: 12px;
    border-width: 0;
    opacity: 0;
    box-shadow: none;
    pointer-events: none;
    visibility: hidden;
}

.lesson-hint-line {
    margin: 0;
    font-size: 13px;
    line-height: 1.55;
    color: #3d4558;
}

.lesson-hint-line + .lesson-hint-line {
    margin-top: 6px;
}

.lesson-hint-em {
    color: #0d5aa7;
    font-weight: 600;
}

.lesson-toast {
    position: absolute;
    left: 50%;
    bottom: calc(100% + 8px);
    transform: translateX(-50%) translateY(8px);
    padding: 10px 22px;
    font-size: 15px;
    font-weight: 600;
    color: #fff;
    background: linear-gradient(135deg, #16a34a 0%, #15803d 100%);
    border-radius: 999px;
    box-shadow: 0 4px 14px rgba(22, 101, 52, 0.35);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.35s ease, transform 0.35s ease, visibility 0.35s ease;
    white-space: nowrap;
    z-index: 6;
}

.lesson-toast.lesson-toast--visible {
    visibility: visible;
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

.lesson-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    align-items: center;
}

.lesson-btn {
    cursor: pointer;
    padding: 10px 18px;
    font-size: 15px;
    border: 1px solid rgba(140, 160, 210, 0.45);
    border-radius: 10px;
    background: linear-gradient(180deg, #fefeff 0%, #f3f5fd 100%);
    color: #2f3542;
    box-shadow: 0 2px 8px rgba(100, 110, 160, 0.1);
}

.lesson-btn:hover:not(:disabled) {
    background: linear-gradient(180deg, #fff 0%, #e8f0ff 100%);
    border-color: #8ab4f0;
}

.lesson-btn:disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

.lesson-btn-secondary {
    color: #555;
    border-color: #bbb;
}

.lesson-btn-secondary:hover:not(:disabled) {
    background: #f5f5f5;
    border-color: #999;
}

/* removes tap blinking on ios devices */
* { -webkit-tap-highlight-color:rgba(0,0,0,0); }


.v3d-simple-preloader-logo {
    background-image: url('media/logo180.png');
}