/* CSS Variables - Strict Bitcoin.org Style */
:root {
    --color-brand-orange: #f7931a;
    --color-brand-orange-hover: #ff9f2d;
    --color-dark-bg: #1a1c23;
    --color-darker-bg: #111318;
    --color-text-main: #333333;
    --color-text-muted: #666666;
    --color-text-light: #ffffff;
    --color-text-light-muted: #a0a4b8;
    --color-border: #e0e0e0;
    --color-border-dark: #2a2d38;
    --font-main: 'Inter', 'Noto Sans SC', sans-serif;
    --transition-speed: 0.2s;
}

/* Reset & Base Setup */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-main);
    color: var(--color-text-main);
    background-color: #ffffff;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

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

ul {
    list-style: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation Bar */
.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 80px;
    background-color: #ffffff;
    border-bottom: 1px solid transparent;
    position: -webkit-sticky;
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-brand {
    font-size: 24px;
    font-weight: 700;
    color: var(--color-text-main);
    display: flex;
    align-items: center;
    gap: 8px;
    font-style: normal;
}

.nav-brand i {
    color: var(--color-brand-orange);
    font-style: normal;
}

.nav-logo-img {
    width: 36px;
    height: 36px;
    display: block;
    flex-shrink: 0;
    object-fit: contain;
}

.nav-links {
    display: flex;
    gap: 40px;
}

.nav-links a {
    font-size: 15px;
    color: var(--color-text-main);
    display: flex;
    align-items: center;
    gap: 6px;
}

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

.nav-links a.nav-link-active {
    color: var(--color-brand-orange);
    font-weight: 600;
    position: relative;
}

.nav-links a.nav-link-active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--color-brand-orange);
    border-radius: 2px;
}

.nav-links i {
    font-size: 10px;
    color: #999;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 20px;
    font-size: 15px;
}

/* Language Switcher */
.lang-switcher {
    position: relative;
}

.lang-trigger {
    display: flex;
    align-items: center;
    gap: 6px;
    background: none;
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: 7px 12px;
    font-size: 14px;
    font-family: var(--font-main);
    color: var(--color-text-main);
    cursor: pointer;
    transition: border-color var(--transition-speed), background var(--transition-speed);
    white-space: nowrap;
}

.lang-trigger:hover {
    border-color: var(--color-brand-orange);
    background: #fff8f0;
}

.lang-arrow {
    font-size: 11px;
    transition: transform 0.2s;
}

.lang-trigger[aria-expanded="true"] .lang-arrow {
    transform: rotate(180deg);
}

.lang-dropdown {
    display: none;
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    min-width: 148px;
    background: #ffffff;
    border: 1px solid var(--color-border);
    border-radius: 10px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.10);
    padding: 6px 0;
    z-index: 1000;
    animation: langDropFadeIn 0.15s ease;
}

.lang-dropdown-open {
    display: block;
}

@keyframes langDropFadeIn {
    from { opacity: 0; transform: translateY(-6px); }
    to   { opacity: 1; transform: translateY(0); }
}

.lang-item {
    display: flex;
    align-items: center;
    gap: 9px;
    padding: 9px 16px;
    font-size: 14px;
    color: var(--color-text-main);
    text-decoration: none;
    transition: background var(--transition-speed), color var(--transition-speed);
    white-space: nowrap;
}

.lang-item:hover {
    background: #fff8f0;
    color: var(--color-brand-orange);
}

.lang-item-active {
    color: var(--color-brand-orange);
    font-weight: 600;
}

.lang-flag {
    font-size: 16px;
    line-height: 1;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 90px 20px 0;
    background: linear-gradient(160deg, #fff9f2 0%, #ffffff 55%, #f5f8ff 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background-image: radial-gradient(circle, #e8e8e8 1px, transparent 1px);
    background-size: 28px 28px;
    opacity: 0.45;
    pointer-events: none;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: rgba(247, 147, 26, 0.1);
    color: var(--color-brand-orange);
    border: 1px solid rgba(247, 147, 26, 0.25);
    border-radius: 100px;
    padding: 5px 16px;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.04em;
    margin-bottom: 24px;
    position: relative;
}

.hero-title {
    font-size: 52px;
    font-weight: 700;
    color: var(--color-text-main);
    max-width: 820px;
    margin: 0 auto 36px;
    line-height: 1.25;
    position: relative;
}

.hero-title-brand {
    color: var(--color-brand-orange);
}

.hero-title-sub {
    display: block;
    font-size: 0.55em;
    font-weight: 400;
    color: var(--color-text-muted);
    margin-top: 12px;
    letter-spacing: 0.02em;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-bottom: 52px;
    flex-wrap: wrap;
    position: relative;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 13px 28px;
    font-size: 15px;
    font-weight: 600;
    border-radius: 100px;
    cursor: pointer;
    transition: all var(--transition-speed);
    white-space: nowrap;
}

.btn-primary {
    background-color: var(--color-brand-orange);
    color: #ffffff;
    border: 2px solid var(--color-brand-orange);
    box-shadow: 0 4px 18px rgba(247, 147, 26, 0.32);
}

.btn-primary:hover {
    background-color: var(--color-brand-orange-hover);
    border-color: var(--color-brand-orange-hover);
    box-shadow: 0 6px 24px rgba(247, 147, 26, 0.45);
    transform: translateY(-1px);
}

.btn-outline {
    background-color: #ffffff;
    color: var(--color-text-main);
    border: 2px solid #e0e0e0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.btn-outline:hover {
    border-color: var(--color-brand-orange);
    color: var(--color-brand-orange);
    transform: translateY(-1px);
}

.hero-video-link {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    font-size: 15px;
    color: var(--color-text-main);
    margin-bottom: 60px;
    cursor: pointer;
}

.hero-video-link .play-icon {
    width: 44px;
    height: 44px;
    background-color: var(--color-dark-bg);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    padding-left: 3px;
    transition: background-color var(--transition-speed);
}

.hero-video-link:hover .play-icon {
    background-color: var(--color-brand-orange);
}

/* Hero Platform Tabs */
.hero-platforms {
    margin-bottom: 50px;
    position: relative;
}

.hero-platforms-label {
    font-size: 11px;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--color-text-muted);
    margin-bottom: 14px;
}

.platform-tabs {
    display: inline-flex;
    gap: 4px;
    background: rgba(255,255,255,0.8);
    border: 1px solid #e8e8e8;
    border-radius: 12px;
    padding: 6px;
    margin-bottom: 18px;
    flex-wrap: wrap;
    justify-content: center;
    box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    backdrop-filter: blur(8px);
}

.platform-tab {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
    padding: 10px 20px;
    background: transparent;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-family: var(--font-main);
    font-size: 12px;
    color: var(--color-text-muted);
    transition: all var(--transition-speed);
    min-width: 76px;
    line-height: 1;
    text-decoration: none;
}

.platform-tab i {
    font-size: 22px;
}

.platform-tab:hover {
    color: var(--color-brand-orange);
    background: rgba(247, 147, 26, 0.08);
}

/* Hero SVG Graphic Network */
.hero-graphic {
    width: 100%;
    display: block;
    margin-bottom: -1px;
}

/* Dark Overview Section */
.overview-section {
    background-color: var(--color-dark-bg);
    padding: 80px 20px 100px;
    color: var(--color-text-light);
    text-align: center;
    position: relative;
}

.overview-title {
    font-size: 24px;
    font-weight: 400;
    margin-bottom: 40px;
}

.overview-grid {
    display: flex;
    justify-content: center;
    gap: 20px;
    max-width: 900px;
    margin: 0 auto;
    flex-wrap: wrap;
}

.overview-card {
    background-color: var(--color-darker-bg);
    flex: 1;
    min-width: 250px;
    padding: 50px 30px;
    border-radius: 2px;
    transition: transform var(--transition-speed), box-shadow var(--transition-speed);
    display: flex;
    flex-direction: column;
    align-items: center;
    border: 1px solid transparent;
}

.overview-card:hover {
    border-color: rgba(247, 147, 26, 0.3);
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
}

.card-icon {
    font-size: 40px;
    color: var(--color-brand-orange);
    margin-bottom: 25px;
    font-weight: 300;
}

.card-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 10px;
}

.card-desc {
    font-size: 13px;
    color: var(--color-text-light-muted);
    margin-bottom: 15px;
    line-height: 1.5;
}

.card-link {
    font-size: 13px;
    color: var(--color-brand-orange);
    margin-top: auto;
}

.card-link:hover {
    text-decoration: underline;
}

/* Section Arrow Down */
.section-arrow-down {
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%) translateY(50%);
    width: 50px;
    height: 50px;
    background-color: var(--color-darker-bg);
    transform-origin: center;
    transform: translateX(-50%) translateY(50%) rotate(45deg);
    z-index: 10;
}

.section-arrow-down i {
    position: absolute;
    bottom: 10px;
    right: 10px;
    transform: rotate(-45deg);
    color: var(--color-brand-orange);
    font-size: 18px;
}

/* Core Features Section */
.features-section {
    background-color: #ffffff;
    padding: 120px 20px 80px;
}

.features-header {
    text-align: center;
    margin-bottom: 60px;
}

.features-header h2 {
    font-size: 32px;
    font-weight: 400;
    color: var(--color-text-main);
    margin-bottom: 15px;
}

.features-header p {
    color: var(--color-text-muted);
    max-width: 600px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 50px 80px;
    max-width: 1000px;
    margin: 0 auto;
}

.feature-item {
    display: flex;
    align-items: flex-start;
    gap: 20px;
}

.feature-icon {
    font-size: 32px;
    color: var(--color-brand-orange);
    flex-shrink: 0;
    margin-top: 5px;
}

.feature-text h3 {
    font-size: 20px;
    color: var(--color-text-main);
    margin-bottom: 12px;
    font-weight: 600;
}

.feature-text p {
    font-size: 14px;
    color: var(--color-text-muted);
    line-height: 1.7;
}

/* Downloads Matrix */
.downloads-section {
    background-color: #f9f9f9;
    padding: 80px 20px;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

.downloads-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    max-width: 1100px;
    margin: 40px auto 0;
}

.download-card {
    background: #ffffff;
    border: 1px solid var(--color-border);
    padding: 30px 20px;
    text-align: center;
    border-radius: 2px;
    transition: all var(--transition-speed);
}

.download-card:hover {
    border-color: var(--color-brand-orange);
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}

.download-card i {
    font-size: 40px;
    color: var(--color-text-main);
    margin-bottom: 20px;
}

.download-card h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 8px;
}

.download-card p {
    font-size: 12px;
    color: var(--color-text-muted);
    margin-bottom: 20px;
}

.download-card .btn-link {
    font-size: 14px;
    color: var(--color-brand-orange);
    font-weight: 600;
}

.download-card .btn-link i {
    font-size: 12px;
}

.download-card .btn-link:hover {
    text-decoration: underline;
}

/* Footer */
footer {
    background-color: var(--color-dark-bg);
    color: var(--color-text-light);
    position: relative;
    overflow: hidden;
    padding: 80px 0 40px;
}

.footer-network-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0.5;
    pointer-events: none;
    z-index: 1;
}

.footer-content {
    position: relative;
    z-index: 2;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 60px;
}

.footer-col-brand {
    padding-right: 20px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    color: #ffffff;
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 14px;
    text-decoration: none;
}

.footer-brand:hover {
    color: var(--color-brand-orange);
}

.footer-brand-img {
    width: 32px;
    height: 32px;
    display: block;
    filter: brightness(0) invert(1);
}

.footer-brand-desc {
    font-size: 13px;
    color: var(--color-text-light-muted);
    line-height: 1.7;
    margin-bottom: 20px;
}

.footer-brand-actions {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
}

.footer-gh-link {
    font-size: 13px;
    color: var(--color-text-light-muted);
    display: flex;
    align-items: center;
    gap: 6px;
    transition: color var(--transition-speed);
}

.footer-gh-link:hover {
    color: var(--color-brand-orange);
}

.footer-col h4 {
    font-size: 14px;
    color: #ffffff;
    margin-bottom: 25px;
    font-weight: 600;
}

.footer-col ul li {
    margin-bottom: 15px;
}

.footer-col ul li a {
    font-size: 13px;
    color: var(--color-text-light-muted);
    transition: color var(--transition-speed);
}

.footer-col ul li a:hover {
    color: var(--color-brand-orange);
}

.btn-donate {
    background-color: var(--color-brand-orange);
    color: #fff;
    padding: 8px 20px;
    font-size: 13px;
    border: none;
    border-radius: 2px;
    cursor: pointer;
    font-weight: 600;
    white-space: nowrap;
}

.footer-bottom {
    border-top: 1px solid var(--color-border-dark);
    padding-top: 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 12px;
    color: var(--color-text-light-muted);
    position: relative;
    z-index: 2;
}

/* ===========================
   Stats Band Section
   =========================== */
.stats-section {
    background: var(--color-darker-bg);
    border-top: 1px solid var(--color-border-dark);
    border-bottom: 1px solid var(--color-border-dark);
}

.stats-inner {
    display: flex;
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px;
}

.stat-item {
    flex: 1;
    padding: 64px 24px;
    text-align: center;
    border-right: 1px solid var(--color-border-dark);
}

.stat-item:last-child {
    border-right: none;
}

.stat-num {
    font-size: 58px;
    font-weight: 700;
    color: #ffffff;
    letter-spacing: -2px;
    line-height: 1;
    margin-bottom: 12px;
    font-variant-numeric: tabular-nums;
}

.stat-suffix {
    font-size: 40px;
    font-weight: 700;
    color: var(--color-brand-orange);
}

.stat-label {
    font-size: 12px;
    color: var(--color-text-light-muted);
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

/* ===========================
   Protocols Section
   =========================== */
.protocols-section {
    background: #ffffff;
    padding: 100px 20px;
}

.protocols-layout {
    display: grid;
    grid-template-columns: 1fr 1.4fr;
    gap: 80px;
    align-items: center;
    max-width: 1100px;
    margin: 0 auto;
}

.section-label {
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--color-brand-orange);
    margin-bottom: 18px;
}

.protocols-left h2 {
    font-size: 36px;
    font-weight: 400;
    line-height: 1.35;
    margin-bottom: 20px;
    color: var(--color-text-main);
}

.protocols-left p {
    color: var(--color-text-muted);
    line-height: 1.85;
    font-size: 15px;
}

.protocol-list {
    display: flex;
    flex-direction: column;
}

.protocol-row {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px 0;
    border-bottom: 1px solid var(--color-border);
    transition: background var(--transition-speed);
}

.protocol-row:first-child {
    border-top: 1px solid var(--color-border);
}

.protocol-badge {
    width: 42px;
    height: 42px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 10px;
    font-weight: 800;
    letter-spacing: 0.04em;
    flex-shrink: 0;
    color: #fff;
}

.protocol-badge.ss     { background: #f7931a; }
.protocol-badge.vmess  { background: #3b82f6; }
.protocol-badge.trojan { background: #8b5cf6; }
.protocol-badge.snell  { background: #10b981; }
.protocol-badge.socks  { background: #6b7280; }

.protocol-info {
    flex: 1;
}

.protocol-info strong {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--color-text-main);
    margin-bottom: 3px;
}

.protocol-info span {
    font-size: 12px;
    color: var(--color-text-muted);
    line-height: 1.4;
}

.protocol-check {
    color: #10b981;
    font-size: 15px;
    flex-shrink: 0;
}

/* ===========================
   Use Cases / Scenarios Section
   =========================== */
.scenarios-section {
    background: #f5f5f7;
    padding: 100px 20px;
}

.scenarios-heading {
    text-align: center;
    margin-bottom: 80px;
}

.scenarios-heading h2 {
    font-size: 38px;
    font-weight: 400;
    margin-bottom: 14px;
    color: var(--color-text-main);
}

.scenarios-heading p {
    color: var(--color-text-muted);
    font-size: 16px;
    max-width: 600px;
    margin: 0 auto;
}

.scenario-block {
    display: grid;
    grid-template-columns: 110px 1fr;
    gap: 40px;
    max-width: 920px;
    margin: 0 auto 64px;
    padding-bottom: 64px;
    border-bottom: 1px solid #ddd;
}

.scenario-block:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.scenario-number {
    font-size: 80px;
    font-weight: 800;
    color: rgba(0, 0, 0, 0.055);
    line-height: 1;
    letter-spacing: -4px;
    text-align: right;
    padding-top: 6px;
    user-select: none;
}

.scenario-content h3 {
    font-size: 21px;
    font-weight: 600;
    margin-bottom: 14px;
    color: var(--color-text-main);
    line-height: 1.45;
}

.scenario-content p {
    font-size: 15px;
    color: var(--color-text-muted);
    line-height: 1.85;
    margin-bottom: 22px;
}

.scenario-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    list-style: none;
}

.scenario-tags li {
    font-size: 12px;
    background: #fff;
    border: 1px solid #e0e0e0;
    padding: 5px 14px;
    border-radius: 20px;
    color: var(--color-text-muted);
    white-space: nowrap;
}

/* ===========================
   Quick Start / Timeline Section
   =========================== */
.quickstart-section {
    background: var(--color-dark-bg);
    padding: 100px 20px;
    color: #fff;
}

.qs-header {
    text-align: center;
    margin-bottom: 72px;
}

.qs-header h2 {
    font-size: 36px;
    font-weight: 400;
    color: #fff;
    margin-bottom: 12px;
}

.qs-header p {
    color: var(--color-text-light-muted);
    font-size: 16px;
}

.qs-timeline {
    max-width: 780px;
    margin: 0 auto;
}

.qs-step {
    display: grid;
    grid-template-columns: 80px 1fr;
    gap: 32px;
}

.qs-step-left {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.qs-num {
    width: 54px;
    height: 54px;
    border: 2px solid var(--color-brand-orange);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 15px;
    font-weight: 700;
    color: var(--color-brand-orange);
    flex-shrink: 0;
    background: var(--color-dark-bg);
    position: relative;
    z-index: 1;
}

.qs-line {
    width: 2px;
    flex: 1;
    background: var(--color-border-dark);
    margin: 10px 0;
    min-height: 50px;
}

.qs-step-right {
    padding-bottom: 64px;
    min-width: 0;
}

.qs-step:last-child .qs-step-right {
    padding-bottom: 0;
}

.qs-step-right h3 {
    font-size: 20px;
    font-weight: 600;
    color: #fff;
    margin-bottom: 12px;
    margin-top: 14px;
    line-height: 1.4;
}

.qs-step-right p {
    font-size: 14px;
    color: var(--color-text-light-muted);
    line-height: 1.85;
    margin-bottom: 18px;
}

.qs-link {
    font-size: 14px;
    color: var(--color-brand-orange);
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: gap var(--transition-speed);
}

.qs-link:hover {
    gap: 11px;
}

.qs-code-block {
    background: var(--color-darker-bg);
    border: 1px solid var(--color-border-dark);
    border-left: 3px solid var(--color-brand-orange);
    padding: 18px 22px;
    font-family: 'Courier New', 'Consolas', monospace;
    font-size: 13px;
    line-height: 2;
    color: #a0a4b8;
    margin-top: 14px;
    border-radius: 2px;
}

.code-key     { color: #79b8ff; }
.code-val     { color: #f7931a; }
.code-comment { color: #4a5568; }

/* ===========================
   FAQ Accordion Section
   =========================== */
.faq-section {
    background: #ffffff;
    padding: 100px 20px;
}

.faq-header {
    text-align: center;
    margin-bottom: 60px;
}

.faq-header h2 {
    font-size: 36px;
    font-weight: 400;
    margin-bottom: 12px;
    color: var(--color-text-main);
}

.faq-header p {
    color: var(--color-text-muted);
    font-size: 15px;
    max-width: 560px;
    margin: 0 auto;
}

.faq-grid {
    max-width: 860px;
    margin: 0 auto 48px;
}

.faq-item {
    border-bottom: 1px solid var(--color-border);
}

.faq-item:first-child {
    border-top: 1px solid var(--color-border);
}

.faq-question {
    width: 100%;
    background: none;
    border: none;
    padding: 22px 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-size: 16px;
    font-weight: 500;
    color: var(--color-text-main);
    text-align: left;
    gap: 20px;
    font-family: var(--font-main);
    transition: color var(--transition-speed);
}

.faq-question:hover {
    color: var(--color-brand-orange);
}

.faq-icon {
    font-size: 14px;
    color: var(--color-text-muted);
    flex-shrink: 0;
    transition: transform 0.28s ease, color 0.28s ease;
}

.faq-item.open .faq-icon {
    transform: rotate(45deg);
    color: var(--color-brand-orange);
}

.faq-answer {
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.38s ease;
}

.faq-answer.open {
    max-height: 400px;
}

.faq-answer p {
    padding-bottom: 24px;
    font-size: 14px;
    color: var(--color-text-muted);
    line-height: 1.85;
}

.faq-more {
    text-align: center;
}

/* ===========================
   Open Source Community Banner
   =========================== */
.community-section {
    background: linear-gradient(135deg, var(--color-darker-bg) 0%, #1c1206 100%);
    border-top: 1px solid rgba(247, 147, 26, 0.18);
}

.community-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 90px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 48px;
}

.community-text h2 {
    font-size: 32px;
    font-weight: 400;
    color: #fff;
    margin-bottom: 14px;
    margin-top: 12px;
}

.community-text p {
    color: var(--color-text-light-muted);
    max-width: 520px;
    line-height: 1.8;
    font-size: 15px;
}

.community-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 8px;
    background: var(--color-brand-orange);
    color: #fff;
    padding: 28px 48px;
    border-radius: 2px;
    text-align: center;
    transition: background var(--transition-speed), transform var(--transition-speed);
    flex-shrink: 0;
    min-width: 200px;
}

.community-btn:hover {
    background: var(--color-brand-orange-hover);
    transform: translateY(-2px);
}

.community-btn i {
    font-size: 30px;
}

.community-btn span {
    font-size: 15px;
    font-weight: 600;
}

.community-btn small {
    font-size: 12px;
    opacity: 0.75;
}

/* ===========================
   Hamburger & Mobile Drawer
   =========================== */
.nav-burger {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 36px;
    height: 36px;
    padding: 6px;
    background: none;
    border: none;
    cursor: pointer;
    border-radius: 4px;
    transition: background 0.2s;
}
.nav-burger:hover { background: #f5f5f5; }
.nav-burger span {
    display: block;
    width: 100%;
    height: 2px;
    background: #333;
    border-radius: 2px;
    transition: transform 0.25s, opacity 0.25s;
    transform-origin: center;
}
/* Animate to X when open */
.nav-mobile-open .nav-burger span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-mobile-open .nav-burger span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.nav-mobile-open .nav-burger span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-mobile-drawer {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 80px;
    left: 0;
    right: 0;
    background: #fff;
    padding: 12px 0 16px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.08);
    z-index: 200;
}
.nav-mobile-drawer a {
    display: block;
    padding: 13px 24px;
    font-size: 15px;
    color: var(--color-text-main);
    text-decoration: none;
    border-left: 3px solid transparent;
    transition: color 0.2s, border-color 0.2s, background 0.2s;
}
.nav-mobile-drawer a:hover,
.nav-mobile-drawer a.nav-link-active {
    color: var(--color-brand-orange);
    border-left-color: var(--color-brand-orange);
    background: #fffaf5;
}
.nav-mobile-lang {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    padding: 12px 24px 4px;
    border-top: 1px solid var(--color-border);
    margin-top: 8px;
}
.nav-mobile-lang .lang-item {
    display: flex;
    align-items: center;
    gap: 5px;
    padding: 6px 12px;
    font-size: 13px;
    color: #555;
    text-decoration: none;
    border-radius: 4px;
    border: 1px solid var(--color-border);
    transition: border-color 0.2s, color 0.2s;
}
.nav-mobile-lang .lang-item:hover,
.nav-mobile-lang .lang-item-active {
    color: var(--color-brand-orange);
    border-color: var(--color-brand-orange);
}

/* ===========================
   Responsive Design
   =========================== */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .nav-burger { display: flex; }
    .lang-switcher { display: none; }

    /* Fixed header on mobile */
    .navbar {
        position: fixed !important;
        top: 0 !important;
        left: 0;
        right: 0;
        width: 100%;
        box-shadow: 0 1px 8px rgba(0,0,0,0.08);
    }
    body { padding-top: 80px; }

    /* Mobile drawer fixed below header */
    .nav-mobile-open .nav-mobile-drawer {
        display: flex;
        position: fixed;
        top: 80px;
        left: 0;
        right: 0;
    }
    .hero-title { font-size: 34px; }
    .hero-title-sub { font-size: 16px; }
    .features-grid { grid-template-columns: 1fr; gap: 40px; }
    .downloads-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1fr 1fr 1fr; }

    /* Stats */
    .stats-inner { flex-wrap: wrap; }
    .stat-item {
        min-width: 50%;
        border-right: none;
        border-bottom: 1px solid var(--color-border-dark);
    }
    .stat-item:nth-child(odd) { border-right: 1px solid var(--color-border-dark); }

    /* Protocols */
    .protocols-layout { grid-template-columns: 1fr; gap: 48px; }
    .protocols-left h2 { font-size: 28px; }

    /* Community */
    .community-inner { flex-direction: column; text-align: center; }
    .community-text p { margin: 0 auto; }
    .community-btn { width: 100%; max-width: 320px; }

    /* Quick Start */
    .qs-header h2 { font-size: 28px; }
}

@media (max-width: 768px) {
    .hero-title { font-size: 28px; }
    .hero-title-sub { font-size: 15px; }
    .hero-badge { font-size: 11px; }
    .hero-buttons { flex-direction: column; align-items: center; }
    .btn { width: auto; max-width: 100%; white-space: normal; }
    .overview-grid { flex-direction: column; }
    .downloads-grid { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr 1fr; gap: 30px; }
    .footer-bottom { flex-direction: column; gap: 15px; text-align: center; }

    /* Platform tabs */
    .platform-tab { min-width: 60px; padding: 8px 12px; font-size: 11px; }
    .platform-tab i { font-size: 18px; }

    /* Stats */
    .stat-num { font-size: 44px; }
    .stat-suffix { font-size: 30px; }
    .stat-item { min-width: 100%; border-right: none !important; }

    /* Scenarios */
    .scenarios-heading h2 { font-size: 28px; }
    .scenario-block { grid-template-columns: 1fr; gap: 10px; }
    .scenario-number { font-size: 56px; text-align: left; letter-spacing: -2px; }
    .scenario-content h3 { font-size: 18px; }

    /* Quick Start */
    .qs-step { grid-template-columns: 60px 1fr; gap: 20px; }
    .qs-num { width: 44px; height: 44px; font-size: 13px; }
    .qs-step-right h3 { font-size: 17px; }

    /* FAQ */
    .faq-question { font-size: 14px; }
    .faq-header h2 { font-size: 28px; }

    /* Community */
    .community-text h2 { font-size: 26px; }

    /* Protocols */
    .protocols-left h2 { font-size: 26px; }
}