/* ============================================
   KnotLink — 本地应用协作通信协议
   Main Stylesheet
   ============================================ */

/* ----- CSS 变量 ----- */
:root {
    --color-bg:        #0b0d14;
    --color-bg-alt:    #11141e;
    --color-bg-card:   #161924;
    --color-bg-card-hover: #1c2032;
    --color-border:    #1e2235;
    --color-text:      #e0e4f0;
    --color-text-dim:  #8b90a5;
    --color-text-muted:#5b6080;
    --color-accent:    #e5a50a;
    --color-accent-hover: #f5b830;
    --color-accent-glow: rgba(229, 165, 10, 0.3);
    --color-green:     #34d399;
    --color-orange:    #fb923c;
    --color-blue:      #60a5fa;
    --color-pink:      #f472b6;
    --color-cyan:      #22d3ee;

    --font-sans: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
    --font-mono: 'Cascadia Code', 'Fira Code', 'JetBrains Mono', 'Consolas', monospace;

    --radius-sm:  6px;
    --radius-md:  10px;
    --radius-lg:  16px;
    --radius-xl:  24px;

    --shadow-card: 0 1px 3px rgba(0,0,0,.4), 0 0 0 1px var(--color-border);
    --shadow-glow: 0 0 40px var(--color-accent-glow);
}

/* ----- 基础重置 ----- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

a {
    color: inherit;
    text-decoration: none;
}

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

/* ----- 容器 ----- */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ----- 导航栏 ----- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(11, 13, 20, 0.82);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--color-border);
    height: 64px;
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.2rem;
    letter-spacing: -0.3px;
}

.nav-logo-small {
    height: 32px;
    width: auto;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 28px;
    list-style: none;
    font-size: 0.92rem;
}

.nav-links a {
    color: var(--color-text-dim);
    transition: color .2s;
}

.nav-links a:hover {
    color: var(--color-text);
}

.btn-nav {
    padding: 7px 18px;
    background: var(--color-accent);
    color: #fff !important;
    border-radius: var(--radius-sm);
    font-weight: 600;
    transition: background .2s, box-shadow .2s;
}

.btn-nav:hover {
    background: var(--color-accent-hover);
    box-shadow: 0 0 16px var(--color-accent-glow);
}

/* ----- Hero / 首屏 ----- */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 64px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -30%;
    right: -15%;
    width: 700px;
    height: 700px;
    background: radial-gradient(circle, var(--color-accent-glow) 0%, transparent 70%);
    pointer-events: none;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -20%;
    left: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(96, 165, 250, 0.12) 0%, transparent 70%);
    pointer-events: none;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: 60px;
    position: relative;
    z-index: 1;
}

.hero-text {
    max-width: 560px;
}

.hero-brand {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    font-weight: 700;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--color-accent);
    background: rgba(229, 165, 10, 0.1);
    border: 1px solid rgba(229, 165, 10, 0.3);
    padding: 5px 16px;
    border-radius: 99px;
    margin-bottom: 16px;
}
.stage-badge {
    font-size: 0.65rem;
    letter-spacing: 0.5px;
    text-transform: none;
    color: var(--color-text-muted);
    background: rgba(255,255,255,.06);
    padding: 2px 8px;
    border-radius: 99px;
    font-weight: 500;
}

.hero-tagline {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    letter-spacing: -1px;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #e0e4f0 0%, #a5accc 60%, var(--color-accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-desc {
    font-size: 1.2rem;
    color: var(--color-text-dim);
    line-height: 1.8;
    margin-bottom: 36px;
}

.hero-actions {
    display: flex;
    gap: 14px;
    flex-wrap: wrap;
}

.hero-logo {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-logo-img {
    width: 320px;
    height: auto;
    filter: drop-shadow(0 0 40px var(--color-accent-glow));
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50%      { transform: translateY(-14px); }
}

/* ----- 按钮系统 ----- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 24px;
    border-radius: var(--radius-sm);
    font-size: 0.94rem;
    font-weight: 600;
    cursor: pointer;
    transition: all .25s;
    border: none;
    white-space: nowrap;
}

.btn-primary {
    background: var(--color-accent);
    color: #fff;
}

.btn-primary:hover {
    background: var(--color-accent-hover);
    box-shadow: 0 0 24px var(--color-accent-glow);
    transform: translateY(-1px);
}

.btn-outline {
    background: transparent;
    color: var(--color-text-dim);
    border: 1px solid var(--color-border);
}

.btn-outline:hover {
    color: var(--color-text);
    border-color: var(--color-text-dim);
    background: rgba(255,255,255,.03);
}

.btn-lg {
    padding: 14px 32px;
    font-size: 1.05rem;
    border-radius: var(--radius-md);
}

.btn-card {
    display: flex;
    margin-top: 16px;
    background: rgba(255,255,255,.04);
    border: 1px solid var(--color-border);
    color: var(--color-text-dim);
    transition: all .25s;
    justify-content: center;
}

.btn-card:hover {
    background: var(--color-accent);
    color: #fff;
    border-color: var(--color-accent);
}

/* ----- 章节通用 ----- */
.section {
    padding: 100px 0;
}

.section-title {
    font-size: 2.2rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 8px;
}

.section-subtitle {
    color: var(--color-text-dim);
    font-size: 1.05rem;
    margin-bottom: 48px;
}

.section-header-row {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 20px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.section-header-row .section-subtitle {
    margin-bottom: 0;
}

.btn-index {
    flex-shrink: 0;
    margin-top: 6px;
}

/* ----- 我是谁？卡片 ----- */
.whoami {
    background: var(--color-bg-alt);
}

.identity-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.identity-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 36px 28px 28px;
    position: relative;
    transition: all .3s;
    display: flex;
    flex-direction: column;
}

.identity-card:hover {
    background: var(--color-bg-card-hover);
    border-color: rgba(229, 165, 10, 0.3);
    transform: translateY(-4px);
    box-shadow: 0 8px 32px rgba(0,0,0,.3);
}

.card-featured {
    border-color: rgba(229, 165, 10, 0.45);
    box-shadow: 0 0 30px rgba(229, 165, 10, 0.08);
}

.card-badge {
    position: absolute;
    top: 12px;
    right: 16px;
    background: var(--color-accent);
    color: #fff;
    padding: 3px 10px;
    border-radius: 99px;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.card-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    background: rgba(229, 165, 10, 0.12);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 18px;
    color: var(--color-accent);
}

.card-icon svg {
    width: 26px;
    height: 26px;
}

.identity-card h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.identity-card h3 .highlight {
    color: var(--color-accent);
}

.identity-card > p {
    color: var(--color-text-dim);
    font-size: 0.92rem;
    margin-bottom: 16px;
}

.card-features {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 8px;
    flex: 1;
}

.card-features li {
    font-size: 0.88rem;
    color: var(--color-text-dim);
    padding-left: 2px;
}

/* ----- 图标墙 ----- */
.icon-wall {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 16px;
}

.node-icon-item {
    width: 80px;
    height: 80px;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 6px;
    transition: all .3s;
    cursor: default;
}

.node-icon-item:hover {
    border-color: var(--color-accent);
    background: var(--color-bg-card-hover);
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0,0,0,.25);
}

.node-icon-item .icon-char {
    font-size: 1.6rem;
    font-weight: 700;
}

.node-icon-item .icon-label {
    font-size: 0.7rem;
    color: var(--color-text-muted);
    font-weight: 600;
}

.node-wall-logo {
    width: 36px;
    height: 36px;
    object-fit: contain;
    border-radius: var(--radius-sm);
}

/* node colors — only apply to icon-char spans, not images */

/* node colors */
.node-icon-item:nth-child(8n+1) .icon-char { color: var(--color-accent); }
.node-icon-item:nth-child(8n+2) .icon-char { color: var(--color-green); }
.node-icon-item:nth-child(8n+3) .icon-char { color: var(--color-orange); }
.node-icon-item:nth-child(8n+4) .icon-char { color: var(--color-blue); }
.node-icon-item:nth-child(8n+5) .icon-char { color: var(--color-pink); }
.node-icon-item:nth-child(8n+6) .icon-char { color: var(--color-cyan); }
.node-icon-item:nth-child(8n+7) .icon-char { color: var(--color-accent); }
.node-icon-item:nth-child(8n+8) .icon-char { color: var(--color-green); }

/* ----- 配方墙 ----- */
.recipe-wall {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 14px;
    margin-bottom: 40px;
}

.recipe-item {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 16px 18px;
    transition: all .3s;
    cursor: pointer;
}

.recipe-item:hover {
    border-color: rgba(229, 165, 10, 0.4);
    background: var(--color-bg-card-hover);
    transform: translateY(-2px);
}

.recipe-item .recipe-icon {
    font-size: 1.5rem;
    margin-bottom: 8px;
}

.recipe-item .recipe-name {
    font-weight: 700;
    font-size: 0.92rem;
    margin-bottom: 4px;
}

.recipe-item .recipe-desc {
    font-size: 0.78rem;
    color: var(--color-text-muted);
    line-height: 1.5;
}

.recipe-item .recipe-tags {
    display: flex;
    gap: 6px;
    margin-top: 10px;
    flex-wrap: wrap;
}

.recipe-item .recipe-tags span {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 99px;
    font-size: 0.68rem;
    font-weight: 600;
    background: rgba(229, 165, 10, 0.1);
    color: var(--color-accent);
}

/* ----- 典型场景 ----- */
.scenarios-section {
    background: var(--color-bg-alt);
}

.scenario-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.scenario-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 28px 24px;
    transition: all .3s;
}

.scenario-card:hover {
    border-color: rgba(229, 165, 10, 0.35);
    background: var(--color-bg-card-hover);
    transform: translateY(-3px);
    box-shadow: 0 8px 28px rgba(0,0,0,.25);
}

.scenario-icon {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-sm);
    background: rgba(229, 165, 10, 0.1);
    color: var(--color-accent);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 14px;
}

.scenario-icon svg {
    width: 24px;
    height: 24px;
}

.scenario-card h3 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.scenario-card > p {
    font-size: 0.88rem;
    color: var(--color-text-dim);
    line-height: 1.7;
    margin-bottom: 14px;
}

.scenario-tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.scenario-tags span {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 99px;
    font-size: 0.72rem;
    font-weight: 600;
    background: rgba(255,255,255,.04);
    color: var(--color-text-muted);
    border: 1px solid var(--color-border);
}

/* ----- 开源仓库卡片 ----- */
.repo-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.repo-card { background: var(--color-bg-card); border: 1px solid var(--color-border); border-radius: var(--radius-lg); padding: 22px; transition: all .25s; display: block; text-decoration: none; color: inherit; }
.repo-card:hover { border-color: rgba(229, 165, 10,.35); background: var(--color-bg-card-hover); transform: translateY(-2px); }
.repo-card .repo-icon { font-size: 1.4rem; margin-bottom: 6px; }
.repo-card h4 { font-size: 0.95rem; font-weight: 700; font-family: var(--font-mono); margin-bottom: 2px; }
.repo-card p { font-size: 0.8rem; color: var(--color-text-dim); margin-bottom: 6px; }
.repo-card .repo-lang { font-size: 0.7rem; color: var(--color-text-muted); }
@media (max-width: 768px) { .repo-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 480px) { .repo-grid { grid-template-columns: 1fr; } }

/* ----- CTA 横幅 ----- */
.cta-box {
    background: linear-gradient(135deg, rgba(229, 165, 10, 0.12) 0%, rgba(96, 165, 250, 0.06) 100%);
    border: 1px solid rgba(229, 165, 10, 0.25);
    border-radius: var(--radius-xl);
    padding: 60px 40px;
    text-align: center;
}

.cta-box h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.cta-box p {
    color: var(--color-text-dim);
    font-size: 1.05rem;
    margin-bottom: 28px;
}

.cta-actions {
    display: flex;
    gap: 14px;
    justify-content: center;
    flex-wrap: wrap;
}

/* ----- 页脚 ----- */
.footer {
    border-top: 1px solid var(--color-border);
    padding: 56px 0 24px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-brand p {
    color: var(--color-text-dim);
    font-size: 0.9rem;
    margin-top: 12px;
}

.footer-logo {
    height: 36px;
    width: auto;
}

.footer-links h4 {
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--color-text-muted);
    margin-bottom: 14px;
}

.footer-links a {
    display: block;
    color: var(--color-text-dim);
    font-size: 0.9rem;
    margin-bottom: 8px;
    transition: color .2s;
}

.footer-links a:hover {
    color: var(--color-text);
}

.footer-bottom {
    border-top: 1px solid var(--color-border);
    padding-top: 20px;
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.82rem;
}

/* ----- 响应式 ----- */
@media (max-width: 968px) {
    .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 40px;
    }

    .hero-text {
        max-width: 100%;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-logo-img {
        width: 200px;
    }

    .hero-tagline {
        font-size: 2.2rem;
    }

    .identity-cards {
        grid-template-columns: 1fr;
    }

    .scenario-grid {
        grid-template-columns: 1fr 1fr;
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 640px) {
    .nav-links {
        display: none;
    }

    .hero-tagline {
        font-size: 1.7rem;
    }

    .hero-desc {
        font-size: 1rem;
    }

    .section {
        padding: 64px 0;
    }

    .section-title {
        font-size: 1.6rem;
    }

    .scenario-grid {
        grid-template-columns: 1fr;
    }

    .recipe-wall {
        grid-template-columns: repeat(2, 1fr);
    }

    .section-header-row {
        flex-direction: column;
    }

    .footer-grid {
        grid-template-columns: 1fr;
    }
}