/* ===== Global common styles: reset, layout, header, nav, footer ===== */

/* Reset & base */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
html, body {
    height: 100%;
}
body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
    color: #e5e7eb;
}
a {
    color: inherit;
    text-decoration: none;
}

/* Page wrapper (二级页通用容器，可以给所有非首页用) */
.page {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    opacity: 0;
    transition: opacity 1.3s ease;
}
.page.fade-in {
    opacity: 1;
}

/* ===== Top bar ===== */
.hero-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.25rem 2.5rem;
}
.logo {
    font-weight: 800;
    letter-spacing: 0.12em;
    font-size: 1.2rem;
    background: #000;
    color: #fff;
    padding: 0.3rem 0.6rem;
    text-transform: uppercase;
}
.logo:hover {
    opacity: 0.8;
}
.right-controls {
    display: flex;
    align-items: center;
    gap: 1.25rem;
    color: #9ca3af;
    font-size: 0.9rem;
}
.social-links a {
    font-size: 0.9rem;
}

/* Language toggle（如果暂时不用也可以保留，将来多语言方便复用） */
.lang-toggle {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.15rem 0.6rem;
    border-radius: 999px;
    border: 1px solid rgba(148, 163, 184, 0.6);
    background: rgba(15, 23, 42, 0.85);
    color: #e5e7eb;
    font-size: 0.7rem;
    cursor: pointer;
    outline: none;
}
.lang-toggle:hover {
    background: rgba(15, 23, 42, 1);
}
.lang-toggle .lang-option {
    opacity: 0.6;
}
.lang-toggle .lang-option.active {
    opacity: 1;
    font-weight: 600;
}
.lang-toggle .lang-separator {
    opacity: 0.4;
}

/* ===== Hamburger menu button ===== */
.menu-toggle {
    border: none;
    background: transparent;
    cursor: pointer;
    padding: 0;
    width: 28px;
    height: 20px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.menu-bar {
    height: 2px;
    width: 100%;
    background: #9ca3af;
    transition: transform 0.25s ease, opacity 0.25s ease;
}
.menu-toggle.open .bar-top {
    transform: translateY(9px) rotate(45deg);
}
.menu-toggle.open .bar-middle {
    opacity: 0;
}
.menu-toggle.open .bar-bottom {
    transform: translateY(-9px) rotate(-45deg);
}

/* ===== Right-side overlay nav ===== */
.nav-overlay {
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    background: rgba(255, 255, 255, 0.7);

    position: fixed;
    inset: 0;
    color: #000000;
    display: flex;
    justify-content: flex-end;
    align-items: flex-start;
    padding: 2rem 3rem;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.25s ease;
    z-index: 20;
}
.nav-overlay.open {
    opacity: 1;
    pointer-events: auto;
}
.nav-close {
    position: absolute;
    top: 1.5rem;
    right: 2.5rem;
    font-size: 1.6rem;
    cursor: pointer;
    background: none;
    border: none;
    box-shadow: none;
    padding: 0;
    line-height: 1;
}
.nav-menu {
    margin-top: 3.5rem;
    text-align: right;
}
.nav-menu a {
    display: block;
    font-size: 2rem;
    margin-bottom: 1.2rem;
    font-weight: 400;
}
.nav-menu a:hover {
    opacity: 0.7;
}

/* ===== Footer (通用) ===== */
footer {
    padding: 1.5rem 1.5rem 2rem;
    max-width: 900px;
    margin: 0 auto;
    font-size: 0.8rem;
    color: #6b7280;
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
}
footer a {
    color: #9ca3af;
}
footer a:hover {
    color: #e5e7eb;
}

/* ===== Responsive (通用) ===== */
@media (max-width: 768px) {
    .hero-header {
        padding: 1rem 1.25rem;
    }
    .nav-overlay {
        padding: 2rem 1.5rem;
    }
    .nav-close {
        right: 1.5rem;
    }
}