/**
 * Global Styles
 * 全局样式
 */

/* ==================== Reset & Base ==================== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    font-size: var(--text-base);
    font-weight: var(--font-normal);
    line-height: var(--leading-normal);
    color: var(--color-text);
    background-color: var(--color-bg);
    min-height: 100vh;
    overflow-x: hidden;
}

/* ==================== Typography ==================== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: var(--font-semibold);
    line-height: var(--leading-tight);
    color: var(--color-text);
}

h1 { font-size: var(--text-5xl); }
h2 { font-size: var(--text-4xl); }
h3 { font-size: var(--text-3xl); }
h4 { font-size: var(--text-2xl); }
h5 { font-size: var(--text-xl); }
h6 { font-size: var(--text-lg); }

p {
    margin-bottom: var(--space-md);
    color: var(--color-text-secondary);
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-accent-light);
}

/* ==================== Container ==================== */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* ==================== Selection ==================== */
::selection {
    background-color: var(--color-accent);
    color: var(--color-primary-dark);
}

/* ==================== Scrollbar ==================== */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--color-primary-light);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-accent);
}

/* ==================== Focus States ==================== */
:focus {
    outline: none;
}

:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* ==================== Images ==================== */
img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ==================== Lists ==================== */
ul, ol {
    list-style: none;
}

/* ==================== Forms ==================== */
button,
input,
select,
textarea {
    font-family: inherit;
    font-size: inherit;
    line-height: inherit;
}

button {
    cursor: pointer;
    border: none;
    background: none;
}

textarea {
    resize: vertical;
}

/* ==================== Tables ==================== */
table {
    border-collapse: collapse;
    width: 100%;
}

/* ==================== Utility Classes ==================== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--color-accent); }
.text-secondary { color: var(--color-text-secondary); }
.text-muted { color: var(--color-text-muted); }

.bg-primary { background-color: var(--color-bg); }
.bg-secondary { background-color: var(--color-bg-secondary); }

.font-heading { font-family: var(--font-heading); }
.font-body { font-family: var(--font-body); }

.gradient-text {
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ==================== Section Styles ==================== */
.section {
    padding: var(--space-section) 0;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--space-3xl);
}

.section-tag {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    font-family: var(--font-heading);
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    color: var(--color-accent);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--space-md);
}

.section-tag::before,
.section-tag::after {
    content: '';
    width: 30px;
    height: 1px;
    background: var(--color-accent);
}

.section-title {
    font-size: var(--text-4xl);
    font-weight: var(--font-bold);
    margin-bottom: var(--space-lg);
    color: var(--color-text);
}

.section-description {
    font-size: var(--text-lg);
    color: var(--color-text-secondary);
    line-height: var(--leading-relaxed);
}

.section-footer {
    text-align: center;
    margin-top: var(--space-3xl);
}

/* ==================== Loading Overlay ==================== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--color-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

.loading-overlay.hidden {
    opacity: 0;
    visibility: hidden;
}

.loader {
    width: 60px;
    height: 60px;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.loader-inner {
    width: 40px;
    height: 40px;
    border: 2px solid var(--color-border-light);
    border-bottom-color: var(--color-accent-light);
    border-radius: 50%;
    animation: spin 0.8s linear infinite reverse;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ==================== Back to Top ==================== */
.back-to-top {
    position: fixed;
    bottom: var(--space-xl);
    right: var(--space-xl);
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-primary-light);
    color: var(--color-accent);
    border-radius: var(--radius-full);
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition-base);
    z-index: var(--z-sticky);
}

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

.back-to-top:hover {
    background: var(--color-accent);
    color: var(--color-primary-dark);
}

/* ==================== Module Visibility ==================== */
.module-hidden {
    display: none !important;
}

body[data-layout="compact"] .section {
    padding: var(--space-3xl) 0;
}

body[data-layout="spacious"] .section {
    padding: var(--space-section) 0;
}