/* 全局过渡与动画追加样式 */

/* 卡片悬停微动画 */
.card {
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
                box-shadow 0.3s cubic-bezier(0.4, 0, 0.2, 1), 
                border-color 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05);
    border-color: var(--muted);
}

/* 按钮悬停动画 */
.btn {
    position: relative;
    overflow: hidden;
}

.btn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.4s ease, height 0.4s ease;
}

.btn:hover::after {
    width: 200%;
    height: 200%;
}

.btn-outline::after {
    background: rgba(17, 17, 17, 0.05);
}

/* 链接下划线动画 */
.nav-links a {
    position: relative;
}

.nav-links a:not(.btn)::after {
    content: '';
    position: absolute;
    width: 0;
    height: 1px;
    bottom: -4px;
    left: 0;
    background-color: var(--fg);
    transition: width 0.3s ease;
}

.nav-links a:not(.btn):hover::after,
.nav-links a.active:not(.btn)::after {
    width: 100%;
}

/* 滚动出现 (Fade Up) 动画 */
.fade-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s cubic-bezier(0.4, 0, 0.2, 1), 
                transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.fade-up.visible {
    opacity: 1;
    transform: translateY(0);
}

/* 动画延迟类 */
.delay-100 { transition-delay: 0.1s; }
.delay-200 { transition-delay: 0.2s; }
.delay-300 { transition-delay: 0.3s; }
.delay-400 { transition-delay: 0.4s; }

/* SVG Logo 交互动画 */
.logo-svg {
    height: 32px;
    width: auto;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.logo-svg:hover {
    transform: scale(1.05);
}

.logo-cloud, .logo-cloud-inner {
    stroke-dasharray: 100;
    stroke-dashoffset: 0;
    transition: stroke-dashoffset 0.6s ease;
}

.logo-svg:hover .logo-cloud {
    stroke-dashoffset: 100;
    animation: draw-cloud 2s linear infinite;
}

.logo-svg:hover .logo-cloud-inner {
    stroke-dashoffset: -100;
    animation: draw-cloud-reverse 2s linear infinite;
}

@keyframes draw-cloud {
    0% { stroke-dashoffset: 100; }
    50% { stroke-dashoffset: 0; }
    100% { stroke-dashoffset: -100; }
}

@keyframes draw-cloud-reverse {
    0% { stroke-dashoffset: -100; }
    50% { stroke-dashoffset: 0; }
    100% { stroke-dashoffset: 100; }
}

.logo-svg .logo-text {
    transition: fill 0.3s ease;
}

.logo-svg:hover .logo-text {
    fill: #d32f2f; /* 悬停时文字变为红色呼应云朵 */
}