/* =========================================================
   PMAI LAB — PREMIUM BLOGS PAGE
   Step 15.3
   File: assets/css/blogs.css

   Design:
   International Academic / Research Platform
   Compatible with Step 15.2 blogs.html
========================================================= */


/* =========================================================
   BLOG DESIGN VARIABLES
========================================================= */

:root {

    --blog-max-width: 1180px;

    --blog-primary: #0f172a;
    --blog-secondary: #1e293b;
    --blog-accent: #2563eb;

    --blog-text: #1f2937;
    --blog-muted: #64748b;

    --blog-border: #e2e8f0;

    --blog-surface: #f8fafc;

    --blog-white: #ffffff;

    --blog-radius-sm: 10px;
    --blog-radius-md: 16px;
    --blog-radius-lg: 22px;
    --blog-radius-xl: 28px;

    --blog-shadow:
        0 10px 30px rgba(
            15,
            23,
            42,
            0.06
        );

    --blog-shadow-hover:
        0 20px 50px rgba(
            15,
            23,
            42,
            0.11
        );

}


/* =========================================================
   BLOG CONTAINER
========================================================= */

.blogs-container {

    width: min(
        calc(100% - 40px),
        var(--blog-max-width)
    );

    margin: 0 auto;

}


/* =========================================================
   BLOG HERO
========================================================= */

.blogs-hero {

    position: relative;

    overflow: hidden;

    padding: 120px 0 105px;

    background:
        linear-gradient(
            135deg,
            #ffffff 0%,
            #f8fafc 52%,
            #eff6ff 100%
        );

    border-bottom:
        1px solid var(--blog-border);

}


/* Decorative circle */

.blogs-hero::before {

    content: "";

    position: absolute;

    width: 430px;
    height: 430px;

    top: -230px;
    right: -100px;

    border-radius: 50%;

    border:
        1px solid rgba(
            37,
            99,
            235,
            0.08
        );

    background:
        rgba(
            37,
            99,
            235,
            0.025
        );

}


/* Decorative circle */

.blogs-hero::after {

    content: "";

    position: absolute;

    width: 260px;
    height: 260px;

    bottom: -160px;
    left: -100px;

    border-radius: 50%;

    border:
        1px solid rgba(
            15,
            23,
            42,
            0.06
        );

}


/* Hero content */

.blogs-hero .blogs-container {

    position: relative;

    z-index: 2;

}


.blogs-hero .section-label {

    margin-bottom: 18px;

}


.blogs-hero h1 {

    max-width: 900px;

    margin: 0 0 25px;

    color: var(--blog-primary);

    font-size:
        clamp(
            3rem,
            7vw,
            5.6rem
        );

    line-height: 1.02;

    letter-spacing: -0.055em;

}


.blogs-hero-description {

    max-width: 780px;

    margin: 0;

    color: var(--blog-muted);

    font-size: 1.08rem;

    line-height: 1.85;

}


/* =========================================================
   HERO ACTIONS
========================================================= */

.blogs-hero-actions {

    display: flex;

    flex-wrap: wrap;

    gap: 13px;

    margin-top: 35px;

}


.blogs-hero-actions .btn {

    display: inline-flex;

    align-items: center;

    justify-content: center;

    min-height: 46px;

    padding: 12px 21px;

    border-radius:
        var(--blog-radius-sm);

    font-size: 0.8rem;

    font-weight: 800;

    text-decoration: none;

    transition:
        transform 0.25s ease,
        background 0.25s ease,
        border-color 0.25s ease,
        color 0.25s ease;

}


.blogs-hero-actions .btn:hover {

    transform:
        translateY(-2px);

}


.blogs-hero-actions .btn-primary {

    background:
        var(--blog-primary);

    color:
        var(--blog-white);

}


.blogs-hero-actions .btn-primary:hover {

    background:
        var(--blog-accent);

}


.blogs-hero-actions .btn-secondary {

    border:
        1px solid var(--blog-border);

    background:
        var(--blog-white);

    color:
        var(--blog-primary);

}


.blogs-hero-actions .btn-secondary:hover {

    border-color:
        var(--blog-accent);

    color:
        var(--blog-accent);

}


/* =========================================================
   CATEGORY NAVIGATION
========================================================= */

.blog-category-section {

    position: sticky;

    top: 0;

    z-index: 20;

    padding: 16px 0;

    background:
        rgba(
            255,
            255,
            255,
            0.94
        );

    border-bottom:
        1px solid var(--blog-border);

    backdrop-filter:
        blur(14px);

}


.blog-category-nav {

    display: flex;

    align-items: center;

    gap: 9px;

    overflow-x: auto;

    scrollbar-width: none;

}


.blog-category-nav::-webkit-scrollbar {

    display: none;

}


.blog-category-nav a {

    display: inline-flex;

    align-items: center;

    justify-content: center;

    flex-shrink: 0;

    min-height: 40px;

    padding:
        0 16px;

    border:
        1px solid var(--blog-border);

    border-radius: 999px;

    background:
        var(--blog-white);

    color:
        var(--blog-secondary);

    font-size:
        0.76rem;

    font-weight: 750;

    text-decoration: none;

    transition:
        background 0.25s ease,
        color 0.25s ease,
        border-color 0.25s ease,
        transform 0.25s ease;

}


.blog-category-nav a:hover {

    transform:
        translateY(-2px);

    border-color:
        var(--blog-primary);

    background:
        var(--blog-primary);

    color:
        var(--blog-white);

}


/* =========================================================
   COMMON SECTION HEADING
========================================================= */

.blog-section-heading {

    margin-bottom:
        42px;

}


.blog-section-heading .section-label {

    margin-bottom:
        12px;

}


.blog-section-heading h2 {

    max-width:
        800px;

    margin:
        0 0 15px;

    color:
        var(--blog-primary);

    font-size:
        clamp(
            2rem,
            4vw,
            3rem
        );

    line-height:
        1.12;

    letter-spacing:
        -0.035em;

}


.blog-section-heading p {

    max-width:
        730px;

    margin:
        0;

    color:
        var(--blog-muted);

    line-height:
        1.8;

}


/* =========================================================
   FEATURED ARTICLE
========================================================= */

.featured-blog-section {

    padding:
        100px 0;

    background:
        var(--blog-white);

}


.featured-blog-card {

    display:
        grid;

    grid-template-columns:
        minmax(0, 1.08fr)
        minmax(0, 0.92fr);

    overflow:
        hidden;

    min-height:
        470px;

    border:
        1px solid var(--blog-border);

    border-radius:
        var(--blog-radius-xl);

    background:
        var(--blog-white);

    box-shadow:
        var(--blog-shadow);

    transition:
        transform 0.35s ease,
        box-shadow 0.35s ease;

}


.featured-blog-card:hover {

    transform:
        translateY(-5px);

    box-shadow:
        var(--blog-shadow-hover);

}


/* =========================================================
   FEATURED VISUAL
========================================================= */

.featured-blog-image {

    position:
        relative;

    display:
        flex;

    align-items:
        flex-end;

    min-height:
        470px;

    padding:
        42px;

    overflow:
        hidden;

    background:
        linear-gradient(
            135deg,
            #020617 0%,
            #0f172a 48%,
            #1e3a8a 100%
        );

}


/* Large mathematical circle */

.featured-blog-image::before {

    content:
        "∑  ∫  ∇  π";

    position:
        absolute;

    top:
        45px;

    right:
        35px;

    color:
        rgba(
            255,
            255,
            255,
            0.08
        );

    font-size:
        4rem;

    font-weight:
        700;

    letter-spacing:
        14px;

}


/* Decorative circle */

.featured-blog-image::after {

    content:
        "";

    position:
        absolute;

    width:
        420px;

    height:
        420px;

    right:
        -170px;

    bottom:
        -200px;

    border:
        1px solid
        rgba(
            255,
            255,
            255,
            0.15
        );

    border-radius:
        50%;

}


/* Featured image content */

.featured-blog-image-content {

    position:
        relative;

    z-index:
        3;

    color:
        var(--blog-white);

}


.featured-blog-image-content span {

    display:
        inline-flex;

    margin-bottom:
        18px;

    padding:
        7px 12px;

    border:
        1px solid
        rgba(
            255,
            255,
            255,
            0.25
        );

    border-radius:
        999px;

    color:
        #dbeafe;

    font-size:
        0.67rem;

    font-weight:
        800;

    letter-spacing:
        0.12em;

}


.featured-blog-image-content h3 {

    margin:
        0;

    color:
        var(--blog-white);

    font-size:
        clamp(
            2.5rem,
            5vw,
            4.2rem
        );

    line-height:
        1.02;

    letter-spacing:
        -0.05em;

}


/* =========================================================
   FEATURED CONTENT
========================================================= */

.featured-blog-content {

    display:
        flex;

    flex-direction:
        column;

    justify-content:
        center;

    padding:
        55px;

}


.blog-meta {

    display:
        flex;

    flex-wrap:
        wrap;

    align-items:
        center;

    gap:
        9px 15px;

    margin-bottom:
        18px;

    color:
        var(--blog-muted);

    font-size:
        0.7rem;

    font-weight:
        800;

    letter-spacing:
        0.06em;

}


.featured-blog-content h3 {

    margin:
        0 0 18px;

    color:
        var(--blog-primary);

    font-size:
        clamp(
            1.8rem,
            3vw,
            2.5rem
        );

    line-height:
        1.18;

    letter-spacing:
        -0.035em;

}


.featured-blog-content p {

    margin:
        0 0 28px;

    color:
        var(--blog-muted);

    line-height:
        1.8;

}


/* =========================================================
   READ MORE
========================================================= */

.blog-read-more {

    display:
        inline-flex;

    align-items:
        center;

    gap:
        8px;

    width:
        fit-content;

    color:
        var(--blog-primary);

    font-size:
        0.82rem;

    font-weight:
        800;

    text-decoration:
        none;

    transition:
        gap 0.25s ease,
        color 0.25s ease;

}


.blog-read-more:hover {

    gap:
        13px;

    color:
        var(--blog-accent);

}


/* =========================================================
   ARTICLES SECTION
========================================================= */

.blogs-grid-section {

    padding:
        100px 0;

    background:
        var(--blog-surface);

}


/* =========================================================
   SEARCH
========================================================= */

.blog-search {

    margin-bottom:
        35px;

}


.blog-search input {

    width:
        100%;

    height:
        54px;

    padding:
        0 18px;

    border:
        1px solid var(--blog-border);

    border-radius:
        var(--blog-radius-sm);

    outline:
        none;

    background:
        var(--blog-white);

    color:
        var(--blog-primary);

    font:
        inherit;

    box-shadow:
        0 4px 14px
        rgba(
            15,
            23,
            42,
            0.03
        );

    transition:
        border-color 0.25s ease,
        box-shadow 0.25s ease;

}


.blog-search input::placeholder {

    color:
        #94a3b8;

}


.blog-search input:focus {

    border-color:
        var(--blog-accent);

    box-shadow:
        0 0 0 4px
        rgba(
            37,
            99,
            235,
            0.08
        );

}


/* =========================================================
   BLOG GRID
========================================================= */

.blog-grid {

    display:
        grid;

    grid-template-columns:
        repeat(
            3,
            minmax(
                0,
                1fr
            )
        );

    gap:
        24px;

}


/* =========================================================
   BLOG CARD
========================================================= */

.blog-card {

    display:
        flex;

    flex-direction:
        column;

    min-width:
        0;

    overflow:
        hidden;

    border:
        1px solid var(--blog-border);

    border-radius:
        var(--blog-radius-lg);

    background:
        var(--blog-white);

    box-shadow:
        var(--blog-shadow);

    transition:
        transform 0.3s ease,
        border-color 0.3s ease,
        box-shadow 0.3s ease;

}


.blog-card:hover {

    transform:
        translateY(-7px);

    border-color:
        #cbd5e1;

    box-shadow:
        var(--blog-shadow-hover);

}


/* =========================================================
   BLOG CARD VISUAL
========================================================= */

.blog-card-image {

    position:
        relative;

    display:
        flex;

    align-items:
        flex-end;

    height:
        190px;

    padding:
        24px;

    overflow:
        hidden;

    background:
        linear-gradient(
            135deg,
            #f1f5f9,
            #e2e8f0
        );

}


.blog-card-image::before {

    content:
        "";

    position:
        absolute;

    width:
        180px;

    height:
        180px;

    top:
        -75px;

    right:
        -55px;

    border:
        1px solid
        rgba(
            15,
            23,
            42,
            0.09
        );

    border-radius:
        50%;

}


.blog-card-image::after {

    content:
        "";

    position:
        absolute;

    width:
        100px;

    height:
        100px;

    bottom:
        -55px;

    left:
        -35px;

    border:
        1px solid
        rgba(
            15,
            23,
            42,
            0.08
        );

    border-radius:
        50%;

}


.blog-card-image span {

    position:
        relative;

    z-index:
        2;

    color:
        var(--blog-primary);

    font-size:
        0.7rem;

    font-weight:
        900;

    letter-spacing:
        0.14em;

}


/* =========================================================
   BLOG CARD CONTENT
========================================================= */

.blog-card-content {

    display:
        flex;

    flex-direction:
        column;

    flex:
        1;

    padding:
        27px;

}


.blog-category {

    display:
        inline-flex;

    width:
        fit-content;

    margin-bottom:
        15px;

    padding:
        6px 10px;

    border:
        1px solid var(--blog-border);

    border-radius:
        999px;

    color:
        var(--blog-secondary);

    background:
        #f8fafc;

    font-size:
        0.62rem;

    font-weight:
        900;

    letter-spacing:
        0.08em;

}


.blog-card h3 {

    margin:
        0 0 13px;

    color:
        var(--blog-primary);

    font-size:
        1.28rem;

    line-height:
        1.3;

    letter-spacing:
        -0.025em;

}


.blog-card p {

    margin:
        0 0 24px;

    color:
        var(--blog-muted);

    font-size:
        0.88rem;

    line-height:
        1.75;

}


/* =========================================================
   BLOG CARD FOOTER
========================================================= */

.blog-card-footer {

    display:
        flex;

    align-items:
        center;

    justify-content:
        space-between;

    gap:
        15px;

    margin-top:
        auto;

    padding-top:
        19px;

    border-top:
        1px solid var(--blog-border);

}


/* =========================================================
   BLOG AUTHOR
========================================================= */

.blog-author {

    display:
        flex;

    align-items:
        center;

    gap:
        9px;

    min-width:
        0;

}


.blog-author-avatar {

    display:
        flex;

    align-items:
        center;

    justify-content:
        center;

    width:
        37px;

    height:
        37px;

    flex-shrink:
        0;

    border-radius:
        50%;

    background:
        var(--blog-primary);

    color:
        var(--blog-white);

    font-size:
        0.62rem;

    font-weight:
        900;

}


.blog-author-info {

    display:
        flex;

    flex-direction:
        column;

    min-width:
        0;

}


.blog-author-info strong {

    overflow:
        hidden;

    color:
        var(--blog-primary);

    font-size:
        0.72rem;

    font-weight:
        800;

    text-overflow:
        ellipsis;

    white-space:
        nowrap;

}


.blog-author-info span {

    color:
        var(--blog-muted);

    font-size:
        0.65rem;

}


/* =========================================================
   BLOG CARD BUTTON
========================================================= */

.blog-card-button {

    display:
        inline-flex;

    align-items:
        center;

    justify-content:
        center;

    flex-shrink:
        0;

    min-height:
        37px;

    padding:
        0 13px;

    border:
        1px solid var(--blog-primary);

    border-radius:
        8px;

    background:
        var(--blog-primary);

    color:
        var(--blog-white);

    font-size:
        0.67rem;

    font-weight:
        800;

    text-decoration:
        none;

    transition:
        transform 0.25s ease,
        background 0.25s ease,
        color 0.25s ease;

}


.blog-card-button:hover {

    transform:
        translateY(-2px);

    background:
        var(--blog-accent);

    border-color:
        var(--blog-accent);

}


/* =========================================================
   TOPICS SECTION
========================================================= */

.blog-topics-section {

    padding:
        100px 0;

    background:
        var(--blog-white);

}


.blog-topics-grid {

    display:
        grid;

    grid-template-columns:
        repeat(
            4,
            minmax(
                0,
                1fr
            )
        );

    gap:
        17px;

}


/* =========================================================
   TOPIC CARD
========================================================= */

.blog-topic-card {

    position:
        relative;

    padding:
        28px;

    overflow:
        hidden;

    border:
        1px solid var(--blog-border);

    border-radius:
        var(--blog-radius-md);

    background:
        var(--blog-white);

    transition:
        transform 0.3s ease,
        border-color 0.3s ease,
        box-shadow 0.3s ease;

}


.blog-topic-card::after {

    content:
        "";

    position:
        absolute;

    width:
        90px;

    height:
        90px;

    right:
        -45px;

    bottom:
        -45px;

    border-radius:
        50%;

    background:
        #f1f5f9;

}


.blog-topic-card:hover {

    transform:
        translateY(-5px);

    border-color:
        #cbd5e1;

    box-shadow:
        var(--blog-shadow);

}


.blog-topic-number {

    display:
        block;

    margin-bottom:
        20px;

    color:
        var(--blog-accent);

    font-size:
        0.65rem;

    font-weight:
        900;

    letter-spacing:
        0.12em;

}


.blog-topic-card h3 {

    position:
        relative;

    z-index:
        2;

    margin:
        0 0 10px;

    color:
        var(--blog-primary);

    font-size:
        1.05rem;

    line-height:
        1.3;

}


.blog-topic-card p {

    position:
        relative;

    z-index:
        2;

    margin:
        0;

    color:
        var(--blog-muted);

    font-size:
        0.78rem;

    line-height:
        1.7;

}


/* =========================================================
   COLLABORATIVE KNOWLEDGE SECTION
========================================================= */

.blog-newsletter {

    padding:
        100px 0;

    background:
        var(--blog-primary);

    color:
        var(--blog-white);

}


/* Main layout */

.blog-newsletter-inner {

    display:
        grid;

    grid-template-columns:
        minmax(
            0,
            1fr
        )
        minmax(
            300px,
            0.72fr
        );

    gap:
        60px;

    align-items:
        center;

}


/* Label */

.blog-newsletter .section-label {

    color:
        #93c5fd;

}


/* Heading */

.blog-newsletter h2 {

    max-width:
        720px;

    margin:
        0 0 18px;

    color:
        var(--blog-white);

    font-size:
        clamp(
            2.2rem,
            5vw,
            3.6rem
        );

    line-height:
        1.08;

    letter-spacing:
        -0.04em;

}


/* Paragraph */

.blog-newsletter p {

    max-width:
        700px;

    margin:
        0;

    color:
        #cbd5e1;

    line-height:
        1.85;

}


/* =========================================================
   CONTRIBUTOR BOX
========================================================= */

.blog-newsletter .blog-empty-state {

    padding:
        38px;

    border:
        1px solid
        rgba(
            255,
            255,
            255,
            0.14
        );

    border-radius:
        var(--blog-radius-lg);

    background:
        rgba(
            255,
            255,
            255,
            0.05
        );

    text-align:
        left;

}


.blog-newsletter .blog-empty-state h3 {

    margin:
        0 0 12px;

    color:
        var(--blog-white);

    font-size:
        1.35rem;

}


.blog-newsletter .blog-empty-state p {

    color:
        #cbd5e1;

    font-size:
        0.86rem;

    line-height:
        1.75;

}


/* =========================================================
   DARK SECTION BUTTON
========================================================= */

.blog-newsletter .blog-card-button {

    background:
        var(--blog-white);

    border-color:
        var(--blog-white);

    color:
        var(--blog-primary);

}


.blog-newsletter .blog-card-button:hover {

    background:
        #dbeafe;

    border-color:
        #dbeafe;

}


/* =========================================================
   FINAL CTA OVERRIDE
========================================================= */

/*
   The HTML uses the same blog-newsletter class
   for the final white CTA.
*/

.blog-newsletter[style*="background: #ffffff"] {

    background:
        var(--blog-white);

    color:
        var(--blog-primary);

    border-top:
        1px solid var(--blog-border);

}


.blog-newsletter[style*="background: #ffffff"]
.section-label {

    color:
        var(--blog-accent);

}


.blog-newsletter[style*="background: #ffffff"]
.blog-card-button {

    background:
        var(--blog-primary);

    border-color:
        var(--blog-primary);

    color:
        var(--blog-white);

}


.blog-newsletter[style*="background: #ffffff"]
.blog-card-button:hover {

    background:
        var(--blog-accent);

    border-color:
        var(--blog-accent);

    color:
        var(--blog-white);

}


/* =========================================================
   FOOTER
========================================================= */

#site-footer {

    padding:
        30px 20px;

    border-top:
        1px solid var(--blog-border);

    background:
        var(--blog-white);

    text-align:
        center;

}


#site-footer p {

    margin:
        0;

    color:
        var(--blog-muted);

    font-size:
        0.72rem;

    line-height:
        1.6;

}


/* =========================================================
   FOCUS ACCESSIBILITY
========================================================= */

.blogs-hero a:focus-visible,
.blog-category-nav a:focus-visible,
.blog-card a:focus-visible,
.blog-search input:focus-visible {

    outline:
        3px solid
        rgba(
            37,
            99,
            235,
            0.35
        );

    outline-offset:
        3px;

}


/* =========================================================
   RESPONSIVE — 1100px
========================================================= */

@media (max-width: 1100px) {

    .blog-grid {

        grid-template-columns:
            repeat(
                2,
                minmax(
                    0,
                    1fr
                )
            );

    }


    .blog-topics-grid {

        grid-template-columns:
            repeat(
                2,
                minmax(
                    0,
                    1fr
                )
            );

    }

}


/* =========================================================
   RESPONSIVE — 900px
========================================================= */

@media (max-width: 900px) {

    .featured-blog-card {

        grid-template-columns:
            1fr;

    }


    .featured-blog-image {

        min-height:
            350px;

    }


    .featured-blog-content {

        padding:
            42px;

    }


    .blog-newsletter-inner {

        grid-template-columns:
            1fr;

        gap:
            40px;

    }

}


/* =========================================================
   RESPONSIVE — 700px
========================================================= */

@media (max-width: 700px) {

    .blogs-container {

        width:
            min(
                calc(100% - 28px),
                var(--blog-max-width)
            );

    }


    /* Hero */

    .blogs-hero {

        padding:
            78px 0 70px;

    }


    .blogs-hero h1 {

        font-size:
            3rem;

        letter-spacing:
            -0.045em;

    }


    .blogs-hero-description {

        font-size:
            0.95rem;

    }


    .blogs-hero-actions {

        flex-direction:
            column;

        align-items:
            stretch;

    }


    .blogs-hero-actions .btn {

        width:
            100%;

    }


    /* Sections */

    .featured-blog-section,
    .blogs-grid-section,
    .blog-topics-section,
    .blog-newsletter {

        padding:
            72px 0;

    }


    /* Featured */

    .featured-blog-image {

        min-height:
            290px;

        padding:
            28px;

    }


    .featured-blog-image-content h3 {

        font-size:
            2.7rem;

    }


    .featured-blog-content {

        padding:
            30px;

    }


    /* Article grid */

    .blog-grid {

        grid-template-columns:
            1fr;

        gap:
            20px;

    }


    /* Topics */

    .blog-topics-grid {

        grid-template-columns:
            1fr;

    }


    /* Card footer */

    .blog-card-footer {

        align-items:
            flex-start;

        flex-direction:
            column;

    }


    .blog-card-button {

        width:
            100%;

    }


    /* Dark section */

    .blog-newsletter .blog-empty-state {

        padding:
            28px;

    }

}


/* =========================================================
   RESPONSIVE — 480px
========================================================= */

@media (max-width: 480px) {

    .blogs-hero h1 {

        font-size:
            2.5rem;

    }


    .blogs-hero-description {

        font-size:
            0.9rem;

        line-height:
            1.75;

    }


    .blog-section-heading h2 {

        font-size:
            2rem;

    }


    .featured-blog-image {

        min-height:
            250px;

        padding:
            24px;

    }


    .featured-blog-image-content h3 {

        font-size:
            2.3rem;

    }


    .featured-blog-content {

        padding:
            25px;

    }


    .blog-card-content {

        padding:
            23px;

    }


    .blog-card-image {

        height:
            165px;

    }


    .blog-topic-card {

        padding:
            23px;

    }


    .blog-newsletter-inner {

        gap:
            30px;

    }


    .blog-newsletter h2 {

        font-size:
            2.1rem;

    }

}


/* =========================================================
   REDUCED MOTION
========================================================= */

@media (prefers-reduced-motion: reduce) {

    .blogs-hero-actions .btn,
    .blog-category-nav a,
    .featured-blog-card,
    .blog-read-more,
    .blog-card,
    .blog-card-button,
    .blog-topic-card {

        transition:
            none !important;

    }

}