:root {
    --bg: #f2f5f9;
    --card: #ffffff;
    --text: #1f2937;
    --muted: #6b7280;
    --primary: #1f4d8b;
    --primary-dark: #163a69;
    --border: #e5e7eb;
    --shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg);
    color: var(--text);
    scroll-behavior: smooth;
}

.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    width: 100%;
    background: rgba(255, 255, 255, 0.2);
    z-index: 999;
}

#progressFill {
    display: block;
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, #38bdf8, #1f4d8b);
    transition: width 0.2s ease;
}

.guide-header {
    background: linear-gradient(135deg, #1a365d, #2d5a87);
    color: #fff;
    padding: 28px 0;
    box-shadow: var(--shadow);
}

.header-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    flex-wrap: wrap;
}

.brand {
    display: flex;
    align-items: center;
    gap: 16px;
}

.brand img {
    width: 64px;
    height: 64px;
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.2);
    padding: 6px;
}

.brand h1 {
    font-size: 28px;
    margin-bottom: 4px;
}

.brand p {
    color: rgba(255, 255, 255, 0.8);
    font-size: 14px;
}

.header-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.primary-btn,
.ghost-btn {
    text-decoration: none;
    padding: 10px 18px;
    border-radius: 10px;
    font-weight: 600;
    border: 1px solid transparent;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.ghost-btn {
    color: #fff;
    border-color: rgba(255, 255, 255, 0.4);
}

.primary-btn:hover,
.ghost-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 18px rgba(15, 23, 42, 0.15);
}

.guide-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 32px 24px 60px;
}

.guide-intro {
    background: var(--card);
    padding: 18px 20px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 24px;
    color: var(--muted);
}

.guide-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 28px;
    position: sticky;
    top: 12px;
    z-index: 3;
    background: var(--bg);
    padding: 8px 0;
}

.guide-nav a {
    background: var(--card);
    border: 1px solid var(--border);
    color: var(--primary);
    padding: 8px 12px;
    border-radius: 999px;
    text-decoration: none;
    font-size: 13px;
    font-weight: 600;
    transition: all 0.2s ease;
}

.guide-nav a.active,
.guide-nav a:hover {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

.guide-tools {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.guide-tools input {
    flex: 1;
    min-width: 220px;
    padding: 12px 14px;
    border-radius: 12px;
    border: 1px solid var(--border);
    font-size: 14px;
}

.tool-actions {
    display: flex;
    gap: 10px;
}

.ghost-btn.small {
    padding: 8px 12px;
    font-size: 12px;
    border: 1px solid var(--border);
    background: var(--card);
    color: var(--primary);
}

.guide-section {
    background: var(--card);
    border-radius: 14px;
    padding: 22px;
    box-shadow: var(--shadow);
    margin-bottom: 18px;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.guide-section:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 24px rgba(15, 23, 42, 0.12);
}

.section-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
}

.section-toggle {
    border: none;
    background: rgba(31, 77, 139, 0.1);
    color: var(--primary);
    padding: 6px 12px;
    border-radius: 999px;
    font-size: 12px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.section-toggle:hover {
    background: var(--primary);
    color: #fff;
}

.guide-section h2 {
    font-size: 20px;
    margin-bottom: 8px;
}

.guide-section .where {
    color: var(--muted);
    font-size: 13px;
    margin-bottom: 10px;
}

.guide-section ul {
    list-style: disc;
    padding-left: 18px;
    color: var(--text);
    line-height: 1.6;
    font-size: 14px;
}

.section-body {
    overflow: hidden;
    max-height: 1200px;
    transition: max-height 0.3s ease, opacity 0.3s ease;
}

.guide-section.collapsed .section-body {
    opacity: 0;
}

.reveal {
    opacity: 0;
    transform: translateY(14px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

.two-col {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
}

.card {
    background: #f8fafc;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px;
}

.card h3 {
    font-size: 16px;
    margin-bottom: 8px;
}

.back-to-top {
    position: fixed;
    right: 24px;
    bottom: 24px;
    padding: 10px 14px;
    border-radius: 999px;
    border: none;
    background: var(--primary);
    color: #fff;
    font-weight: 600;
    cursor: pointer;
    box-shadow: var(--shadow);
    opacity: 0;
    pointer-events: none;
    transform: translateY(10px);
    transition: all 0.2s ease;
    z-index: 10;
}

.back-to-top.show {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}

@media (max-width: 720px) {
    .header-inner {
        flex-direction: column;
        align-items: flex-start;
    }
}