/* === 1. Design Tokens (CSS Custom Properties) === */
:root {
    /* Color Palette */
    --color-primary: rgb(0, 0, 0);
    --color-primary-dark: #005ba1;
    --color-primary-light: #e8f4fd;
    --color-text: rgb(40, 40, 40);
    --color-text-secondary: #555555;
    --color-text-muted: rgb(40, 40, 40);
    --color-text-light: #bbbbbb;
    --color-bg: rgb(238, 238, 238);
    --color-bg-alt: #f5f5f5;
    --color-bg-hero: #e8e8e8;
    --color-bg-dark: #1a1a1a;
    --color-bg-gray: #f3f3f3;
    --color-bg-overlay: rgba(255, 255, 255, 0.95);
    --color-border: rgb(234, 234, 234);
    --color-border-light: #eeeeee;
    --color-white: #ffffff;
    --color-black: #000000;
    --color-border-table: rgb(0, 0, 0);
    /* Typography */
    --font-family: "Source Han Sans SC VF", sans-serif;
    --font-family-en: "DINCond-Bold", Arial, sans-serif;
    --font-family-geo: "Geometr415 Blk BT", Arial, sans-serif;

    --font-size-xs: 12px;
    --font-size-sm: 14px;
    --font-size-base: 16px;
    --font-size-lg: 20px;
    --font-size-xl: 24px;
    --font-size-2xl: 32px;
    --font-size-3xl: 42px;
    --font-size-4xl: 56px;
    --font-size-5xl: 72px;

    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-bold: 700;
    --font-weight-black: 900;
    --line-height-tight: 1.2;
    --line-height-base: 1.6;
    --line-height-loose: 1.8;

    /* Spacing Scale */
    --space-3xs: 2px;
    --space-2xs: 4px;
    --space-xs: 8px;
    --space-sm: 18px;
    --space-md: 24px;
    --space-lg: 32px;
    --space-xl: 48px;
    --space-2xl: 64px;
    --space-3xl: 80px;
    --space-4xl: 120px;
    --space-5xl: 150px;

    /* Layout */
    --container-max: 1400px;
    --container-padding: 40px;
    --header-height: 70px;
    --sidebar-width: 300px;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-nav: 400ms cubic-bezier(0.16, 1, 0.3, 1);

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
    --shadow-dropdown: 0 6px 24px rgba(0, 0, 0, 0.12);

    /* Border Radius */
    --radius-sm: 2px;
    --radius-md: 4px;
    --radius-lg: 8px;

    /* Z-index Scale */
    --z-base: 1;
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-overlay: 500;
    --z-modal: 1000;
}
/*@font-face {*/
/*    font-family: "SourceHanSansCN";*/
/*    src: url("../fonts/SourceHanSansCN-Regular.otf") format("opentype");*/
/*    font-weight: normal;*/
/*    font-style: normal;*/
/*    font-display: swap;*/
/*}*/
/*@font-face {*/
/*    font-family: "SourceHanSansCN";*/
/*    src: url("../fonts/SourceHanSansCN-Bold.otf") format("opentype");*/
/*    font-weight: bold;*/
/*    font-style: normal;*/
/*    font-display: swap;*/
/*}*/
/*@font-face {*/
/*    font-family: "SourceHanSansCN";*/
/*    src: url("../fonts/SourceHanSansCN-ExtraLight.otf") format("opentype");*/
/*    font-weight: 200;*/
/*    font-style: normal;*/
/*    font-display: swap;*/
/*}*/
/*@font-face {*/
/*    font-family: "SourceHanSansCN";*/
/*    src: url("../fonts/SourceHanSansCN-Light.otf") format("opentype");*/
/*    font-weight: 300;*/
/*    font-style: normal;*/
/*    font-display: swap;*/
/*}*/
/*@font-face {*/
/*    font-family: "SourceHanSansCN";*/
/*    src: url("../fonts/SourceHanSansCN-Normal.otf") format("opentype");*/
/*    font-weight: 450;*/
/*    font-style: normal;*/
/*    font-display: swap;*/
/*}*/
/*@font-face {*/
/*    font-family: "SourceHanSansCN";*/
/*    src: url("../fonts/SourceHanSansCN-Medium.otf") format("opentype");*/
/*    font-weight: 500;*/
/*    font-style: normal;*/
/*    font-display: swap;*/
/*}*/
/*@font-face {*/
/*    font-family: "SourceHanSansCN";*/
/*    src: url("../fonts/SourceHanSansCN-Heavy.otf") format("opentype");*/
/*    font-weight: 900;*/
/*    font-style: normal;*/
/*    font-display: swap;*/
/*}*/
/* 英文装饰字体 */
@font-face {
    font-family: "Geometr415 Blk BT";
    src: url("../fonts/Geometr415 Blk BT Black.ttf") format("truetype");
    font-weight: 900;
    font-style: normal;
    font-display: swap;
}
/* 数字装饰字体 */
@font-face {
    font-family: "DINCcond-Bold";
    src: url("../fonts/DINCond-Bold.otf") format("truetype");
    font-weight: 900;
    font-style: normal;
    font-display: swap;
}
/* === 2. CSS Reset === */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: var(--font-size-base);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-normal);
    line-height: var(--line-height-base);
    color: var(--color-text);
    background-color: rgb(255, 255, 255);
}

.common_btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-xs) var(--space-md);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    color: var(--color-bg);
    background-color: var(--color-text);
    border: 2px solid var(--color-text);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

.common_btn:hover {
    background-color: var(--color-primary);
    color: white;
}

/* === Fixed Layout for Desktop/Tablet (>= 769px) === */
/* Prevent layout shrinking when browser window resizes */
@media (min-width: 769px) {
    body {
        min-width: 1400px;
        overflow-x: auto;
    }
}

/* Mobile: allow horizontal overflow hidden */
@media (max-width: 768px) {
    body {
        overflow-x: hidden;
    }
}

img {
    height: auto;
    display: block;
}

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

a:hover {
    color: var(--color-primary);
}

ul,
ol {
    list-style: none;
}

button {
    font-family: inherit;
    font-size: inherit;
    border: none;
    background: none;
    cursor: pointer;
    outline: none;
}

input,
textarea,
select {
    font-family: inherit;
    font-size: inherit;
    outline: none;
}

table {
    border-collapse: collapse;
    width: 100%;
}

/* === 3. Base Styles === */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

.section {
    padding: var(--space-3xl) 0;
}

.section--alt {
    background-color: var(--color-bg-alt);
}

.section__title {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    margin-bottom: var(--space-lg);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.section__title-icon {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
}

.section__title img {
    width: 32px;
    height: 32px;
    object-fit: contain;
    flex-shrink: 0;
}

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

/* === 4. Placeholder Image Handling === */
.img-placeholder {
    background-color: var(--color-bg-alt);
    position: relative;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

.img-placeholder::before {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, var(--color-bg-alt) 0%, #ddd 100%);
    z-index: 0;
}

.img-placeholder__icon {
    position: relative;
    z-index: 1;
    width: 48px;
    height: 48px;
    opacity: 0.3;
}

img[src] {
    background-color: transparent;
}

/* === 5. Page Title (Sub-pages) === */
.page-title {
    padding-top: calc(var(--header-height) + var(--space-3xl));
    padding-bottom: var(--space-3xl);
}

.page-title__heading {
    font-size: var(--font-size-5xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    line-height: var(--line-height-tight);
    white-space: nowrap;
}

.page-title__heading--en {
    font-family: var(--font-family-en);
    font-size: var(--font-size-5xl);
    letter-spacing: 2px;
    white-space: nowrap;
}

.page-title__description {
    font-size: var(--font-size-base);
    color: var(--color-text-secondary);
    line-height: var(--line-height-loose);
    max-width: 600px;
}

.page-title--with-aside {
    background: rgb(234, 234, 234);
    display: flex;
    flex-wrap: nowrap;
    justify-content: start;
    align-items: flex-start;
    gap: var(--space-5xl);
    min-width: fit-content;
}

/* Prevent both children from shrinking */
.page-title--with-aside > div:first-child {
    flex-shrink: 0;
}

.page-title__aside {
    flex-shrink: 0;
    max-width: 800px;
    font-size: var(--font-size-base);
    color: var(--color-text-secondary);
    line-height: var(--line-height-loose);
    padding-top: var(--space-sm);
}

/* Page Title Wrapper */
.page-title__wrapper {
    background: rgb(234, 234, 234);
}

/* === 6. Utility Classes === */
.u-text-center {
    text-align: center;
}
.u-text-right {
    text-align: right;
}
.u-mb-0 {
    margin-bottom: 0;
}
.u-mb-sm {
    margin-bottom: var(--space-sm);
}
.u-mb-md {
    margin-bottom: var(--space-md);
}
.u-mb-lg {
    margin-bottom: var(--space-lg);
}
.u-mb-xl {
    margin-bottom: var(--space-xl);
}
.u-mt-lg {
    margin-top: var(--space-lg);
}
.u-hidden {
    display: none;
}

/* === 7. Animations === */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.animate-fade-in {
    opacity: 0;
    animation: fadeIn var(--transition-slow) forwards;
}

.animate-fade-in-up {
    opacity: 0;
    transform: translateY(30px);
}

.animate-fade-in-up--visible {
    animation: fadeInUp 0.6s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.animate-slide-in-right {
    opacity: 0;
    transform: translateX(30px);
}

.animate-slide-in-right--visible {
    animation: slideInRight 0.6s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

/* Staggered animation delay */
.animate-delay-1 {
    animation-delay: 100ms;
}
.animate-delay-2 {
    animation-delay: 200ms;
}
.animate-delay-3 {
    animation-delay: 300ms;
}
.animate-delay-4 {
    animation-delay: 400ms;
}
.animate-delay-5 {
    animation-delay: 500ms;
}

/* Easy Animation */
.fade-in {
  opacity: 0;
}

.fade-in.visible {
  animation: fadeIn 1s ease-out forwards;
}

@keyframes fadeIn {
  to {
    opacity: 1;
  }
}

.slide-up {
  opacity: 0;
  transform: translateY(100px);
}

.slide-up.visible {
  animation: slideUp 1s ease-out forwards;
}

@keyframes slideUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.slide-left {
  opacity: 0;
  transform: translateX(100px);
}

@keyframes slideLeft {
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.slide-left.visible {
  animation: slideLeft 1s ease-out forwards;
}

.slide-right {
  opacity: 0;
  transform: translateX(-100px);
}

.slide-right.visible {
  animation: slideRight 1s ease-out forwards;
}

@keyframes slideRight {
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.slide-down {
  opacity: 0;
  transform: translateY(-100px);
}

.slide-down.visible {
  animation: slideDown 1s ease-out forwards;
}

@keyframes slideDown {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.zoom-in {
  opacity: 0;
  transform: scale(0.8);
}

.zoom-in.visible {
  animation: zoomIn 1s cubic-bezier(0.35, 1.55, 0.65, 1) forwards;
}

@keyframes zoomIn {
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.blur-in {
  opacity: 0;
  filter: blur(20px);
}

.blur-in.visible {
  animation: blurIn 1s ease-out forwards;
}

@keyframes blurIn {
  to {
    opacity: 1;
    filter: blur(0);
  }
}