/**
 * Crypto Tools - 全局样式表
 *
 * 统一视觉风格与响应式布局，采用 CSS 变量便于后续主题扩展。
 *
 * @package CryptoTools
 * @version 1.0.0
 */

/* ==========================================================================
   1. CSS 变量
   ========================================================================== */

:root {
    --color-primary:       #3b82f6;
    --color-primary-dark:  #2563eb;
    --color-primary-light: #60a5fa;
    --color-accent:        #f59e0b;
    --color-bg:            #0f172a;
    --color-bg-elevated:   #1e293b;
    --color-bg-card:       #1e293b;
    --color-border:        #334155;
    --color-text:          #f1f5f9;
    --color-text-muted:    #94a3b8;
    --color-text-inverse:  #0f172a;

    --font-sans: "Segoe UI", system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;

    --space-xs:  0.25rem;
    --space-sm:  0.5rem;
    --space-md:  1rem;
    --space-lg:  1.5rem;
    --space-xl:  2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;

    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);

    --container-max: 72rem;
    --header-height: 4rem;

    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
}

/* ==========================================================================
   2. 基础重置
   ========================================================================== */

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body.site-body {
    margin: 0;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
}

.skip-link {
    position: absolute;
    top: -100%;
    left: var(--space-md);
    z-index: 9999;
    padding: var(--space-sm) var(--space-md);
    background: var(--color-primary);
    color: #fff;
    border-radius: var(--radius-sm);
    text-decoration: none;
}

.skip-link:focus {
    top: var(--space-md);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

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

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

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

/* ==========================================================================
   3. 布局
   ========================================================================== */

.container {
    width: 100%;
    max-width: var(--container-max);
    margin-inline: auto;
    padding-inline: var(--space-md);
}

@media (min-width: 768px) {
    .container {
        padding-inline: var(--space-xl);
    }
}

/* ==========================================================================
   4. 头部导航
   ========================================================================== */

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    isolation: isolate;
    background: rgba(15, 23, 42, 0.92);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--color-border);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-height);
    gap: var(--space-md);
}

/* 全站页头与首页同宽，避免其它页导航挤换行 */
.site-header > .container {
    max-width: 84rem;
}

.site-logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex-shrink: 0;
    color: var(--color-text);
    font-weight: 700;
    font-size: 1.125rem;
    text-decoration: none;
    white-space: nowrap;
}

.site-logo:hover,
.site-logo:focus-visible {
    color: var(--color-text);
}

.site-logo__icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2rem;
    height: 2rem;
    background: linear-gradient(135deg, var(--color-accent), #d97706);
    border-radius: var(--radius-md);
    font-size: 1rem;
    color: var(--color-text-inverse);
}

.nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 2.5rem;
    height: 2.5rem;
    padding: var(--space-sm);
    background: transparent;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    color: var(--color-text);
}

.nav-toggle__bar {
    display: block;
    width: 100%;
    height: 2px;
    background: currentColor;
    border-radius: 1px;
    transition: transform var(--transition-base), opacity var(--transition-base);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
    opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

@media (min-width: 768px) {
    .nav-toggle {
        display: none;
    }
}

.nav-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.nav-link {
    display: block;
    padding: var(--space-sm) var(--space-md);
    color: var(--color-text-muted);
    border-radius: var(--radius-md);
    font-size: 0.9375rem;
    white-space: nowrap;
    transition: background var(--transition-fast), color var(--transition-fast);
}

.nav-link:hover,
.nav-link:focus-visible,
.nav-link.is-active {
    color: var(--color-text);
    background: var(--color-bg-elevated);
}

@media (max-width: 767px) {
    .site-nav {
        position: absolute;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--color-bg);
        border-bottom: 1px solid var(--color-border);
        padding: var(--space-md);
        display: none;
        box-shadow: var(--shadow-md);
    }

    .site-nav.is-open {
        display: block;
    }
}

@media (min-width: 768px) {
    .site-nav {
        display: block;
        min-width: 0;
    }

    .nav-list {
        flex-direction: row;
        flex-wrap: nowrap;
        align-items: center;
    }
}

/* ==========================================================================
   5. 主内容
   ========================================================================== */

.site-main {
    flex: 1;
    padding-block: var(--space-xl);
}

@media (min-width: 768px) {
    .site-main {
        padding-block: var(--space-2xl);
    }
}

.page-hero {
    text-align: center;
    padding-block: var(--space-xl);
    margin-bottom: var(--space-2xl);
}

.page-home .page-hero {
    padding-block: var(--space-md) var(--space-lg);
    margin-bottom: var(--space-lg);
}

.page-home .page-hero__title {
    margin-bottom: var(--space-sm);
}

@media (min-width: 768px) {
    .page-home .site-main {
        padding-block: var(--space-xl);
    }
}

.page-hero__title {
    margin: 0 0 var(--space-md);
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 800;
    line-height: 1.2;
    background: linear-gradient(135deg, var(--color-text) 0%, var(--color-primary-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.page-hero__subtitle {
    margin: 0 auto;
    max-width: 36rem;
    font-size: 1.0625rem;
    color: var(--color-text-muted);
}

.page-hero--tool {
    text-align: left;
    padding-block: var(--space-lg);
    margin-bottom: var(--space-xl);
    border-bottom: 1px solid var(--color-border);
}

.page-hero--tool .page-hero__title {
    font-size: clamp(1.5rem, 3vw, 2rem);
    background: none;
    -webkit-text-fill-color: unset;
    color: var(--color-text);
}

/* ==========================================================================
   6. 工具卡片（首页）
   ========================================================================== */

.page-home .container {
    max-width: 84rem;
}

.tools-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-md);
    list-style: none;
    margin: 0;
    padding: 0;
}

.tools-grid > li {
    display: flex;
    min-width: 0;
}

@media (min-width: 640px) {
    .tools-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: var(--space-md) var(--space-lg);
    }
}

@media (min-width: 1024px) {
    .tools-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
}

.tool-card {
    display: flex;
    flex-direction: column;
    width: 100%;
    min-height: 9rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-md) var(--space-lg);
    text-decoration: none;
    color: inherit;
    transition: transform var(--transition-base), border-color var(--transition-base), box-shadow var(--transition-base);
}

.tool-card:hover,
.tool-card:focus-visible {
    transform: translateY(-4px);
    border-color: var(--color-primary);
    box-shadow: var(--shadow-lg);
    color: inherit;
}

.tool-card__icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 2.5rem;
    height: 2.5rem;
    margin-bottom: var(--space-sm);
    background: rgba(59, 130, 246, 0.15);
    border-radius: var(--radius-md);
    font-size: 1.25rem;
}

.tool-card__title {
    margin: 0 0 var(--space-xs);
    font-size: 1rem;
    font-weight: 700;
    color: var(--color-text);
}

.tool-card__desc {
    margin: 0 0 var(--space-sm);
    flex: 1;
    font-size: 0.875rem;
    line-height: 1.45;
    color: var(--color-text-muted);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    min-height: 2.5rem;
}

.tool-card__cta {
    margin-top: auto;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-primary-light);
}

/* ==========================================================================
   7. 工具页
   ========================================================================== */

.tool-panel {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
}

.tool-panel__placeholder {
    text-align: center;
    padding: var(--space-3xl) var(--space-md);
    color: var(--color-text-muted);
}

.tool-panel__placeholder-icon {
    font-size: 3rem;
    margin-bottom: var(--space-md);
    opacity: 0.5;
}

.tool-panel__placeholder-text {
    margin: 0;
}

.breadcrumb {
    margin-bottom: var(--space-lg);
}

.breadcrumb__list {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-sm);
    list-style: none;
    margin: 0;
    padding: 0;
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.breadcrumb__item:not(:last-child)::after {
    content: "/";
    margin-left: var(--space-sm);
    color: var(--color-border);
}

.breadcrumb__link {
    color: var(--color-text-muted);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.breadcrumb__link:hover,
.breadcrumb__link:focus-visible {
    color: var(--color-primary-light);
}

.breadcrumb__current {
    color: var(--color-text);
}

/* ==========================================================================
   8. 页脚
   ========================================================================== */

.site-footer {
    margin-top: auto;
    background: var(--color-bg-elevated);
    border-top: 1px solid var(--color-border);
}

.footer-inner {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-xl);
    padding-block: var(--space-2xl);
}

@media (min-width: 768px) {
    .footer-inner {
        grid-template-columns: 2fr 1fr 2fr;
    }
}

.footer-brand__name {
    margin: 0 0 var(--space-xs);
    font-size: 1.125rem;
    font-weight: 700;
}

.footer-brand__tagline {
    margin: 0;
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.footer-nav__title {
    margin: 0 0 var(--space-sm);
    font-size: 0.8125rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
}

.footer-nav__list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
}

.footer-nav__list a {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
}

.footer-disclaimer__text {
    margin: 0;
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    line-height: 1.5;
}

.footer-bottom {
    border-top: 1px solid var(--color-border);
    padding-block: var(--space-md);
}

.footer-copyright {
    margin: 0;
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    text-align: center;
}

/* ==========================================================================
   9. 工具类
   ========================================================================== */

.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;
}

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