/* =================================
   NousBase – First Steps in Python
   Professional Book CSS
   ================================= */

body {
    font-family: "Inter", "Segoe UI", Roboto, Arial, sans-serif;
    background: #f2f3f5;
    margin: 0;
    color: #1f2937;
}

/* ---------- Header ---------- */

.header-bar {
    background: #ffffff;
    border-bottom: 1px solid #e5e7eb;
    padding: 14px 28px;
    display: flex;
    align-items: center;
}

.header-bar img {
    height: 42px;
}

.header-right {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: 18px;
}

.header-right a {
    color: #374151;
    font-size: 1.2rem;
    text-decoration: none;
}

.header-right a:hover {
    color: #2563eb;
}

/* ---------- Book Container ---------- */

.book-container {
    max-width: 860px;
    margin: 50px auto;
    padding: 50px 60px;
    background: #ffffff;
    box-shadow: 0 10px 30px rgba(0,0,0,0.06);
    border-radius: 10px;
}

/* ---------- Chapter Heading ---------- */
.book-title {
    text-align: center;
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 10px;
    color: #444;
}

.chapter-label {
    text-align: center;
    text-transform: uppercase;
    letter-spacing: 2px;
    font-size: 0.85rem;
    color: #6b7280;
    margin-bottom: 8px;
}

.chapter-title {
    text-align: center;
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 45px;
    color: #111827;
}

/* ---------- Text ---------- */

p, li {
    font-size: 1.05rem;
    line-height: 1.85;
}

h3 {
    margin-top: 42px;
    margin-bottom: 16px;
    font-size: 1.35rem;
    font-weight: 600;
}

/* ---------- Code ---------- */

.code-box {
    background: #0f172a;
    color: #e5e7eb;
    padding: 16px 20px;
    border-radius: 8px;
    font-family: Consolas, monospace;
    font-size: 0.95rem;
    margin: 26px 0;
    overflow-x: auto;
}

/* ---------- Notes ---------- */

.note-box {
    background: #eef6ff;
    border-left: 6px solid #2563eb;
    padding: 18px 20px;
    margin: 30px 0;
    border-radius: 6px;
}

/* ---------- GitHub Box ---------- */

.github-box {
    background: #f8fafc;
    border: 1px solid #e5e7eb;
    padding: 18px 22px;
    border-radius: 8px;
    margin: 35px 0;
}

.github-box a {
    font-weight: 600;
    text-decoration: none;
}

/* ---------- Navigation ---------- */

.chapter-nav {
    margin-top: 60px;
    display: flex;
    justify-content: space-between;
}

.chapter-nav a {
    padding: 10px 20px;
    background: #2563eb;
    color: #ffffff;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
}

.chapter-nav a:hover {
    background: #1d4ed8;
}

/* ---------- Footer ---------- */

.book-footer {
    margin-top: 60px;
    padding-top: 24px;
    border-top: 1px solid #e5e7eb;
    text-align: center;
    font-size: 0.95rem;
    color: #6b7280;
}
/* ---------- Progress Unlocked Box ---------- */

.progress-box {
    background: #ecfdf3;              /* soft green background */
    border-left: 6px solid #22c55e;    /* green accent */
    padding: 18px 20px;
    margin: 30px 0;
    border-radius: 6px;
}

.progress-box strong {
    display: block;
    margin-bottom: 10px;
    color: #166534;
    font-size: 1.05rem;
}

.progress-box ul {
    margin: 0;
    padding-left: 20px;
}

.progress-box li {
    margin-bottom: 6px;
}