/* 三国群英传 - 水墨丹青主题 */
:root {
    --水墨黑: #1a1a1a;
    --淡墨灰: #6B6B6B;
    --朱砂印: #B22222;
    --留白: #F8F8F8;
    --远山青: #7B8B6F;
    --card-bg: rgba(255,255,255,0.92);
    --border-color: #E0E0E0;

    --魏灰: #4A5568;
    --蜀青: #5A6B5A;
    --吴赭: #7B5A5A;
    --群褐: #6B5A4A;

    --card-width: 280px;
    --card-height: 420px;
    --card-border: 1px solid var(--border-color);
    --card-radius: 12px;
    --card-shadow: 0 8px 24px rgba(0,0,0,0.12);

    --font-title: 'Ma Shan Zheng', cursive;
    --font-body: 'Noto Serif SC', serif;

    --progress-height: 28px;
    --progress-bg: #E0E0E0;
    --progress-fill: var(--朱砂印);
    --progress-text-color: var(--朱砂印);

    --seal-bg: var(--朱砂印);
    --seal-text: #FFFFFF;
    --seal-size: 40px;
    --seal-radius: 50%;

    /* 统一弹窗尺寸 */
    --modal-width: 75vw;
    --modal-max-width: 1000px;
}

body.dark-mode {
    --留白: #1a1a1a;
    --水墨黑: #e0e0e0;
    --淡墨灰: #999;
    --card-bg: #2a2a2a;
    --border-color: #333;
    --progress-bg: #333;
    --远山青: #4a5a4a;
}

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

html {
    overscroll-behavior-y: contain;
}

body {
    font-family: var(--font-body);
    background: linear-gradient(180deg, #F0F8FA 0%, #E0F0F5 30%, #B8D4E3 70%, #9EC4D8 100%);
    color: var(--水墨黑);
    min-height: 100vh;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -webkit-tap-highlight-color: transparent;
}

h1, h2, h3 {
    font-family: var(--font-title);
    font-weight: normal;
}

/* 水墨青绿背景 - 山峦云雾效果 */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background:
        /* 远山层叠 */
        linear-gradient(180deg, transparent 60%, rgba(100,149,237,0.15) 100%);
    pointer-events: none;
    z-index: -1;
}

/* 山峦剪影层 */
body::after {
    content: '';
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 200px;
    background: linear-gradient(180deg, transparent 0%, rgba(70,130,180,0.12) 100%);
    clip-path: polygon(0% 100%, 0% 70%, 15% 55%, 30% 70%, 45% 50%, 60% 65%, 75% 45%, 90% 60%, 100% 50%, 100% 100%);
    pointer-events: none;
    z-index: -1;
}

/* 滚动条美化 */
::-webkit-scrollbar {
    width: 6px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--淡墨灰);
    border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--朱砂印);
}

/* 统一弹窗面板 */
.modal-panel {
    width: var(--modal-width);
    max-width: var(--modal-max-width);
    background: var(--card-bg);
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    padding: 32px;
    animation: modalIn 0.3s ease;
}

@keyframes modalIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

/* ==================== 回到顶部按钮 ==================== */
.back-to-top {
    position: fixed;
    bottom: 98px;
    right: 32px;
    width: 56px;
    height: 56px;
    border-radius: 50%;
    border: none;
    background: rgba(255,255,255,0.95);
    color: #2C5F7C;
    font-size: 22px;
    cursor: pointer;
    box-shadow: 0 4px 16px rgba(44,95,124,0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    touch-action: manipulation;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: #2C5F7C;
    color: white;
    transform: scale(1.1);
}

/* 手机端回到顶部按钮适配 */
@media (max-width: 480px) {
    .back-to-top {
        bottom: 78px;
        right: 20px;
        width: 48px;
        height: 48px;
        font-size: 20px;
    }
}

/* 手机端弹窗自适应 */
@media (max-width: 768px) {
    .modal-panel {
        width: 95vw;
        padding: 20px;
    }
}