/* ============================================================
   index.css — 首页样式（依赖 base.css 变量）
   ============================================================ */

body {
    font-family: var(--font-body);
    min-height: 100vh;
    background: #2a1a10;
    color: var(--text-primary);
    overflow-x: hidden;
    position: relative;
    will-change: scroll-position;
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
    .intro-overlay,
    .intro-content img,
    .intro-hint,
    .mode-card,
    .nav-btn,
    .title,
    #particles-js canvas {
        animation: none !important;
        transition: none !important;
        transform: none !important;
    }
    .intro-overlay { display: none !important; }
    .main-content { opacity: 1 !important; visibility: visible !important; }
}

/* 木纹/网格背景 */
body::before {
    content: '';
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background-image:
        repeating-linear-gradient(45deg, rgba(100, 60, 20, 0.15) 0px, rgba(100, 60, 20, 0.15) 2px, transparent 2px, transparent 8px),
        linear-gradient(to bottom, transparent 90%, rgba(200, 140, 60, 0.2) 90%),
        linear-gradient(to right, transparent 90%, rgba(200, 140, 60, 0.2) 90%);
    background-size: 20px 20px, 100% 20px, 20px 100%;
    pointer-events: none;
    z-index: 0;
    will-change: transform;
}

body::after {
    content: '';
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: repeating-linear-gradient(transparent, transparent 16.66%, rgba(210, 180, 140, 0.15) 16.66%, rgba(210, 180, 140, 0.15) 16.76%);
    pointer-events: none;
    z-index: 0;
}

/* 粒子画布 */
#particles-js {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    z-index: 1;
    display: block;
    pointer-events: none;
}
#particles-js canvas {
    will-change: transform;
    backface-visibility: hidden;
}

/* ---- 导航按钮 ---- */
.nav-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 18px;
    background: rgba(45, 28, 18, 0.65);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-pill);
    color: var(--text-primary);
    font-size: 15px;
    font-weight: 500;
    text-decoration: none;
    transition: transform 0.2s var(--ease-spring),
                box-shadow 0.25s ease,
                background 0.3s ease,
                border-color 0.3s ease;
    box-shadow: var(--shadow-xs);
    cursor: pointer;
    will-change: transform;
    backface-visibility: hidden;
}
.nav-btn:hover {
    background: rgba(70, 45, 30, 0.8);
    border-color: var(--border-glow);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm), 0 0 20px rgba(240,192,96,0.15);
}
.nav-btn:active {
    transform: translateY(1px);
    transition-duration: 0.05s;
}
.top-left-btn {
    position: absolute;
    top: 20px; left: 20px;
    z-index: 10;
}
.top-right-btn {
    position: absolute;
    top: 20px; right: 20px;
    z-index: 10;
}

/* ---- 主容器 ---- */
.container {
    position: relative;
    z-index: 2;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: center;
}

/* ---- 标题 ---- */
.title {
    font-size: 3.1rem;
    font-weight: 700;
    margin-bottom: 0;
    line-height: 1.1;
    font-family: var(--font-display);
    background: linear-gradient(135deg, var(--gold-bright) 0%, var(--gold-primary) 40%, var(--gold-warm) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 0 18px rgba(240,192,96,0.35));
    animation: fadeInDown 0.9s var(--ease-out);
    letter-spacing: 2px;
    position: relative;
    display: inline-block;
    padding: 0 20px;
}
.title::before, .title::after {
    content: '';
    position: absolute;
    top: 50%;
    width: 32px;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--gold-primary));
    border-radius: 1px;
}
.title::before { left: -40px; }
.title::after { right: -40px; transform: translateY(-50%) scaleX(-1); }

.title-notation {
    width: 200px;
    height: 20px;
    margin: 0 auto 1.5rem auto;
    background: repeating-linear-gradient(90deg, transparent, transparent 15px, #c0a070 15px, #c0a070 20px);
    opacity: 0.5;
}

.subtitle {
    font-size: 2.2rem;
    font-weight: 800;
    font-family: var(--font-display);
    background: linear-gradient(135deg, var(--gold-bright) 0%, var(--gold-primary) 40%, var(--gold-warm) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 0 18px rgba(240,192,96,0.35));
    text-align: center;
    margin: 0.15rem auto 0.1rem auto;
    letter-spacing: 1.5px;
    line-height: 1.3;
    max-width: 580px;
    opacity: 0.88;
    animation: fadeInDown 0.9s var(--ease-out) 0.15s both;
}

@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-25px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ---- 模式卡片网格 ---- */
.mode-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.8rem;
    margin-top: 1rem;
}

.mode-card {
    background: rgba(45, 28, 18, 0.65);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-medium);
    border-radius: var(--radius-xl);
    padding: 1.8rem 1.2rem 2.2rem 1.2rem;
    cursor: pointer;
    transition: transform 0.35s var(--ease-spring),
                box-shadow 0.4s ease,
                border-color 0.4s ease,
                background 0.4s ease;
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    text-align: center;
    animation: fadeInUp 0.8s var(--ease-out) backwards;
    position: relative;
    overflow: hidden;
    outline: none;
    will-change: transform, box-shadow;
    backface-visibility: hidden;
}
.mode-card:focus-visible {
    border-color: var(--gold-warm);
    box-shadow: 0 0 0 3px rgba(212,160,48,0.4);
}
.mode-card:nth-child(1) { animation-delay: 0.05s; }
.mode-card:nth-child(2) { animation-delay: 0.15s; }
.mode-card:nth-child(3) { animation-delay: 0.25s; }

.mode-card::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: var(--radius-xl);
    background: linear-gradient(180deg, rgba(255,255,255,0.04) 0%, transparent 35%);
    pointer-events: none;
    z-index: 2;
}
.mode-card::after {
    content: '';
    position: absolute;
    bottom: 10px;
    left: 15%;
    width: 70%;
    height: 8px;
    background: repeating-linear-gradient(90deg, var(--gold-primary), var(--gold-primary) 4px, transparent 4px, transparent 8px);
    opacity: 0.25;
    border-radius: 2px;
    transition: opacity 0.3s ease;
}

.mode-card:hover {
    transform: translateY(-8px) scale(1.02);
    border-color: var(--border-glow);
    box-shadow: var(--shadow-lg), var(--shadow-glow-strong);
    background: rgba(60, 38, 24, 0.8);
}
.mode-card:hover::after { opacity: 0.45; }
.mode-card:active {
    transform: scale(0.98) translateY(-2px);
    transition: transform 0.08s;
}

.mode-icon {
    font-size: 4.5rem;
    line-height: 1;
    margin-bottom: 1.2rem;
    color: var(--gold-primary);
    filter: drop-shadow(0 0 18px rgba(240,192,96,0.5));
    transition: transform 0.3s var(--ease-spring);
    will-change: transform;
}
.mode-card:hover .mode-icon {
    transform: scale(1.1) rotate(5deg);
    filter: drop-shadow(0 0 28px rgba(240,192,96,0.7));
}

.mode-name {
    font-size: 2rem;
    font-weight: 600;
    color: var(--gold-primary);
    margin-bottom: 0.6rem;
    letter-spacing: 1px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
    font-family: var(--font-display);
}

.mode-desc {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.5;
    opacity: 0.95;
    max-width: 280px;
    margin: 0 auto;
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(25px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ---- 开场动画 ---- */
.intro-overlay {
    position: fixed;
    top: 0; left: 0;
    width: 100vw; height: 100vh;
    background: radial-gradient(ellipse at 50% 40%, #3d2818 0%, #1a0f08 100%);
    z-index: 10000;
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    pointer-events: auto;
    will-change: opacity, background-color;
    cursor: pointer;
    transition: opacity 0.8s cubic-bezier(0.23, 1, 0.32, 1);
}
.intro-overlay::before {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background-image:
        repeating-linear-gradient(45deg, rgba(100, 60, 20, 0.15) 0px, rgba(100, 60, 20, 0.15) 2px, transparent 2px, transparent 8px),
        linear-gradient(to bottom, transparent 90%, rgba(200, 140, 60, 0.2) 90%),
        linear-gradient(to right, transparent 90%, rgba(200, 140, 60, 0.2) 90%);
    background-size: 20px 20px, 100% 20px, 20px 100%;
    pointer-events: none;
    z-index: -1;
}
.intro-overlay::after {
    content: '';
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background: repeating-linear-gradient(transparent, transparent 16.66%, rgba(210, 180, 140, 0.15) 16.66%, rgba(210, 180, 140, 0.15) 16.76%);
    pointer-events: none;
    z-index: -1;
}

.intro-content {
    position: relative;
    width: min(70vw, 500px);
    height: min(70vw, 500px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2;
    perspective: 1000px;
    transform-style: preserve-3d;
}
.intro-content img {
    position: absolute;
    width: 100%; height: 100%;
    object-fit: contain;
    filter: drop-shadow(0 0 20px rgba(255,215,0,0.3));
    opacity: 0;
    will-change: transform, opacity, filter;
    pointer-events: none;
    user-select: none;
    -webkit-user-drag: none;
    transform-style: preserve-3d;
    backface-visibility: hidden;
}

.intro-hint {
    margin-top: 30px;
    color: var(--text-primary);
    font-size: 1.1rem;
    letter-spacing: 3px;
    text-transform: uppercase;
    font-weight: 500;
    font-family: var(--font-body);
    background: rgba(45, 28, 18, 0.5);
    padding: 10px 28px;
    border-radius: var(--radius-pill);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--border-medium);
    transition: all 0.3s var(--ease-out);
    animation: gentlePulse 2s ease-in-out infinite;
    z-index: 2;
    pointer-events: auto;
    cursor: pointer;
    will-change: transform, letter-spacing;
}
.intro-hint:hover {
    background: rgba(212,160,48,0.2);
    border-color: var(--border-glow);
    transform: scale(1.03);
    letter-spacing: 5px;
    box-shadow: 0 0 30px rgba(240,192,96,0.15);
}

@keyframes gentlePulse {
    0% { opacity: 0.5; transform: scale(0.98); box-shadow: 0 0 0 0 rgba(227, 167, 46, 0.3); }
    50% { opacity: 1; transform: scale(1); box-shadow: 0 0 0 8px rgba(227, 167, 46, 0); }
    100% { opacity: 0.5; transform: scale(0.98); box-shadow: 0 0 0 0 rgba(227, 167, 46, 0); }
}

.main-content {
    opacity: 0;
    visibility: hidden;
    transition: opacity 1.2s cubic-bezier(0.23, 1, 0.32, 1), visibility 1.2s;
}
.intro-clickable { cursor: pointer; }

/* ---- 响应式 ---- */
@media (max-width: 768px) {
    .top-left-btn, .top-right-btn { top: 10px; }
    .top-left-btn { left: 10px; }
    .top-right-btn { right: 10px; }
    .nav-btn { padding: 6px 12px; font-size: 14px; }
    .container { padding: 1.5rem 1rem; }
    .title { font-size: 2.6rem; margin-bottom: 0; }
    .title::before, .title::after { font-size: 1.8rem; }
    .title::before { left: -30px; }
    .title::after { right: -30px; }
    .subtitle { font-size: 1.7rem; max-width: 440px; }
    .title-notation { margin-bottom: 1rem; }
    .mode-grid { gap: 1.2rem; }
    .mode-card { padding: 1.5rem 1rem 2rem 1rem; }
    .mode-icon { font-size: 3.5rem; }
    .mode-name { font-size: 1.8rem; }
    .mode-desc { font-size: 0.95rem; }
}

@media (max-width: 380px) {
    .title { font-size: 2.1rem; }
    .title::before, .title::after { display: none; }
    .subtitle { font-size: 1.2rem; max-width: 280px; letter-spacing: 1px; }
}

/* ---- ICP备案 ---- */
.icp-footer {
    position: fixed;
    bottom: 10px;
    left: 0;
    right: 0;
    text-align: center;
    z-index: 100;
    pointer-events: none;
}
.icp-footer a {
    display: inline-block;
    padding: 4px 14px;
    color: var(--text-tertiary);
    font-size: 12px;
    text-decoration: none;
    letter-spacing: 0.5px;
    pointer-events: auto;
    transition: color 0.3s ease;
}
.icp-footer a:hover {
    color: var(--gold-primary);
}

/* ---- 日间主题 ---- */
[data-theme="light"] body {
    background: #ede0cc;
}
[data-theme="light"] body::before {
    background-image:
        repeating-linear-gradient(45deg, rgba(180,150,120,0.12) 0px, rgba(180,150,120,0.12) 2px, transparent 2px, transparent 8px),
        linear-gradient(to bottom, transparent 90%, rgba(180,150,110,0.15) 90%),
        linear-gradient(to right, transparent 90%, rgba(180,150,110,0.15) 90%);
}
[data-theme="light"] body::after {
    background: repeating-linear-gradient(transparent, transparent 16.66%, rgba(180,150,110,0.1) 16.66%, rgba(180,150,110,0.1) 16.76%);
}
[data-theme="light"] .nav-btn {
    background: rgba(240,230,215,0.8);
    color: #3d2e1e;
}
[data-theme="light"] .nav-btn:hover {
    background: rgba(220,200,170,0.9);
    color: #3d2e1e;
}
[data-theme="light"] .mode-card {
    background: rgba(255,248,240,0.7);
}
[data-theme="light"] .mode-card:hover {
    background: rgba(240,220,195,0.85);
}
[data-theme="light"] .intro-overlay {
    background: radial-gradient(ellipse at 50% 40%, #f0e5d4 0%, #e8dcc8 100%);
}
[data-theme="light"] .intro-overlay::before {
    background-image:
        repeating-linear-gradient(45deg, rgba(180,150,120,0.12) 0px, rgba(180,150,120,0.12) 2px, transparent 2px, transparent 8px),
        linear-gradient(to bottom, transparent 90%, rgba(180,150,110,0.15) 90%),
        linear-gradient(to right, transparent 90%, rgba(180,150,110,0.15) 90%);
}
[data-theme="light"] .intro-overlay::after {
    background: repeating-linear-gradient(transparent, transparent 16.66%, rgba(180,150,110,0.1) 16.66%, rgba(180,150,110,0.1) 16.76%);
}
[data-theme="light"] .intro-hint {
    background: rgba(220,200,170,0.5);
    border-color: rgba(180,130,80,0.3);
}
[data-theme="light"] .intro-hint:hover {
    background: rgba(200,170,130,0.4);
}
[data-theme="light"] .title {
    filter: drop-shadow(0 0 12px rgba(180,130,60,0.2));
}
[data-theme="light"] .title::before,
[data-theme="light"] .title::after {
    background: linear-gradient(90deg, transparent, #b87830);
}
[data-theme="light"] .title-notation {
    background: repeating-linear-gradient(90deg, transparent, transparent 15px, #b87830 15px, #b87830 20px);
}
[data-theme="light"] .mode-name {
    text-shadow: 0 1px 2px rgba(0,0,0,0.1);
}
[data-theme="light"] .icp-footer a {
    color: #8b7a6a;
}
[data-theme="light"] .icp-footer a:hover {
    color: #6b5010;
}