/* =========================================================
   blog.css – Trang Blog (BlueArrow007)
   Dùng chung bộ biến :root với trang Home
   ========================================================= */

:root {
    --forest: #1c3a2a;
    --forest-deep: #12261b;
    --sunflower: #f2b705;
    --sunflower-dark: #b48504;
    --mist: #eef2ee;
    --sage: #dbe5dc;
    --ink: #1a261f;
    --ink-soft: #4a5a50;
    --white: #ffffff;

    --font: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI",
        Roboto, sans-serif;
    --radius: 10px;
    --wrap: 1080px;
}

/* ---------- Reset & base ---------- */
*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
    /* tránh header che tiêu đề khi bấm chủ đề */
}

body {
    margin: 0;
    font-family: var(--font);
    font-size: 1rem;
    line-height: 1.65;
    color: var(--ink);
    background: var(--mist);
}

h1,
h2,
h3,
p {
    margin: 0;
}

a {
    color: inherit;
}

ul {
    margin: 0;
    padding: 0;
    list-style: none;
}

:focus-visible {
    outline: 3px solid var(--sunflower);
    outline-offset: 3px;
    border-radius: 4px;
}

/* ---------- Header / Nav ---------- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 10;
    background: var(--forest-deep);
}

.nav {
    max-width: var(--wrap);
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.nav__brand {
    font-weight: 800;
    font-size: 1.125rem;
    color: var(--white);
    text-decoration: none;
    letter-spacing: 0.01em;
}

.nav__list {
    display: flex;
    gap: 1.75rem;
}

.nav__list a {
    position: relative;
    padding: 4px 0;
    font-weight: 500;
    font-size: 0.975rem;
    color: var(--white);
    text-decoration: none;
}

.nav__list a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -2px;
    width: 100%;
    height: 2px;
    background: var(--sunflower);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.25s ease;
}

.nav__list a:hover::after,
.nav__list a[aria-current="page"]::after {
    transform: scaleX(1);
}

/* ---------- Hero ---------- */
.blog-hero {
    background: var(--forest);
    color: var(--white);
    border-bottom: 6px solid var(--sunflower);
}

.blog-hero__inner {
    max-width: var(--wrap);
    margin: 0 auto;
    padding: 4.5rem 1.5rem 3.5rem;
}

.blog-hero__title {
    font-size: clamp(2.25rem, 5vw, 3.5rem);
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.blog-hero__text {
    max-width: 60ch;
    margin-top: 1rem;
    font-size: 1.0625rem;
    color: var(--sage);
}

.topics {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 2rem;
}

.topics__link {
    padding: 0.6rem 1.25rem;
    border-radius: 999px;
    background: var(--sunflower);
    color: var(--forest-deep);
    font-weight: 600;
    font-size: 0.95rem;
    text-decoration: none;
    transition: background 0.2s;
}

.topics__link:hover {
    background: var(--white);
}

/* ---------- Category sections ---------- */
.category {
    max-width: var(--wrap);
    margin: 0 auto;
    padding: 3.5rem 1.5rem;
    display: grid;
    grid-template-columns: 260px 1fr;
    gap: 2.5rem;
}

.category+.category {
    border-top: 1px solid var(--sage);
}

.category__head {
    align-self: start;
    position: sticky;
    top: 96px;
}

.category__title {
    font-size: 1.75rem;
    font-weight: 800;
    line-height: 1.2;
    color: var(--forest);
}

.category__count {
    margin-top: 0.35rem;
    color: var(--ink-soft);
    font-size: 0.9rem;
}

/* ---------- Buttons ---------- */
.btn {
    display: inline-block;
    margin-top: 1.25rem;
    padding: 0.55rem 1.25rem;
    border-radius: 999px;
    font-weight: 600;
    font-size: 0.9rem;
    text-decoration: none;
    transition: background 0.2s, color 0.2s;
}

.btn--outline {
    border: 2px solid var(--forest);
    color: var(--forest);
}

.btn--outline:hover {
    background: var(--forest);
    color: var(--white);
}

/* ---------- Posts ---------- */
.posts {
    display: grid;
    gap: 1rem;
}

.post {
    padding: 1.5rem 1.75rem;
    background: var(--white);
    border: 1px solid var(--sage);
    border-left: 4px solid var(--forest);
    border-radius: var(--radius);
    transition: border-color 0.2s;
}

.post:hover {
    border-left-color: var(--sunflower);
}

.post__title {
    font-size: 1.25rem;
    font-weight: 600;
    line-height: 1.35;
}

.post__title a {
    color: var(--ink);
    text-decoration: none;
}

.post__title a:hover {
    color: var(--forest);
    text-decoration: underline;
    text-decoration-color: var(--sunflower);
    text-decoration-thickness: 2px;
    text-underline-offset: 4px;
}

.post__excerpt {
    max-width: 65ch;
    margin-top: 0.5rem;
    color: var(--ink-soft);
}

.post__more {
    display: inline-block;
    margin-top: 0.85rem;
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--sunflower-dark);
    text-decoration: none;
}

.post__more:hover {
    color: var(--forest);
    text-decoration: underline;
}

/* ---------- Footer ---------- */
.site-footer {
    margin-top: 2rem;
    padding: 1.75rem 1.5rem;
    background: var(--forest-deep);
    color: var(--sage);
    text-align: center;
    font-size: 0.9rem;
}

/* ---------- Responsive ---------- */
@media (max-width: 820px) {
    .category {
        grid-template-columns: 1fr;
        gap: 1.5rem;
        padding: 2.5rem 1.25rem;
    }

    .category__head {
        position: static;
        display: flex;
        flex-wrap: wrap;
        align-items: baseline;
        column-gap: 1rem;
    }

    .category__head .btn {
        margin-top: 0.5rem;
    }
}

@media (max-width: 520px) {
    .nav {
        flex-direction: column;
        gap: 0.5rem;
    }

    .nav__list {
        gap: 1.25rem;
    }

    .blog-hero__inner {
        padding: 3rem 1.25rem 2.5rem;
    }

    .post {
        padding: 1.25rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    * {
        transition: none !important;
    }
}