/* ══════════════════════════════════════════════════════════════════════════
   OWI Blog — Optimal Waste Intelligence
   Editorial design system: clean, authoritative, industrial-precision
   ══════════════════════════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@500;600;700;800&family=Source+Sans+3:ital,wght@0,400;0,500;0,600;1,400&display=swap');

:root {
    --primary-50: #ecfdf5;
    --primary-100: #d1fae5;
    --primary-200: #a7f3d0;
    --primary-300: #6ee7b7;
    --primary-400: #34d399;
    --primary-500: #10b981;
    --primary-600: #059669;
    --primary-700: #047857;
    --primary-800: #065f46;
    --primary-900: #064e3b;

    --gray-50: #f8faf9;
    --gray-100: #f1f4f3;
    --gray-200: #e2e7e5;
    --gray-300: #c8d0cd;
    --gray-400: #8f9e97;
    --gray-500: #637069;
    --gray-600: #4a554f;
    --gray-700: #343d38;
    --gray-800: #1e2722;
    --gray-900: #0f1512;

    --amber-400: #fbbf24;
    --amber-500: #f59e0b;

    --font-display: 'Plus Jakarta Sans', system-ui, sans-serif;
    --font-body: 'Source Sans 3', 'Source Sans Pro', Georgia, serif;

    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;

    --max-width: 700px;
    --max-width-wide: 1080px;
    --radius: 8px;
    --radius-lg: 14px;
    --header-h: 60px;

    --shadow-sm: 0 1px 2px rgba(15, 21, 18, 0.04);
    --shadow-md: 0 4px 16px rgba(15, 21, 18, 0.06);
    --shadow-lg: 0 8px 32px rgba(15, 21, 18, 0.08);
    --shadow-card: 0 1px 3px rgba(15, 21, 18, 0.04), 0 0 0 1px rgba(15, 21, 18, 0.03);
    --shadow-card-hover: 0 8px 24px rgba(4, 120, 87, 0.08), 0 0 0 1px rgba(4, 120, 87, 0.12);
}

/* ── Reset ── */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    scroll-padding-top: calc(var(--header-h) + 1rem);
}

body {
    font-family: var(--font-body);
    color: var(--gray-800);
    background: var(--gray-50);
    line-height: 1.7;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

a {
    color: var(--primary-700);
    text-decoration: none;
    transition: color 0.2s ease;
}
a:hover { color: var(--primary-600); }

img { max-width: 100%; height: auto; display: block; }

/* ══════════════════════════════════════════════════════════════════════════
   HEADER
   ══════════════════════════════════════════════════════════════════════════ */

.site-header {
    background: var(--gray-900);
    height: var(--header-h);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(255,255,255,0.06);
}

.header-inner {
    max-width: var(--max-width-wide);
    margin: 0 auto;
    padding: 0 var(--space-6);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-family: var(--font-display);
    font-weight: 800;
    font-size: 1.05rem;
    color: #fff;
    letter-spacing: -0.01em;
    white-space: nowrap;
    display: flex;
    align-items: center;
    gap: var(--space-3);
}
.logo::before {
    content: "";
    display: inline-block;
    width: 8px;
    height: 8px;
    background: var(--primary-400);
    border-radius: 2px;
    flex-shrink: 0;
}
.logo:hover { color: var(--primary-300); }

/* Desktop nav */
.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-8);
    list-style: none;
    font-family: var(--font-display);
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    text-transform: uppercase;
}
.nav-links a {
    color: var(--gray-400);
    transition: color 0.2s;
    position: relative;
}
.nav-links a:hover { color: #fff; }
.nav-links a::after {
    content: "";
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-400);
    transition: width 0.25s ease;
}
.nav-links a:hover::after { width: 100%; }

/* Hamburger */
.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    width: 32px;
    height: 32px;
    position: relative;
    z-index: 1001;
}
.nav-toggle span,
.nav-toggle span::before,
.nav-toggle span::after {
    display: block;
    width: 22px;
    height: 2px;
    background: #fff;
    border-radius: 1px;
    transition: all 0.3s ease;
    position: absolute;
    left: 5px;
}
.nav-toggle span { top: 15px; }
.nav-toggle span::before { content: ""; top: -7px; }
.nav-toggle span::after { content: ""; top: 7px; }

.nav-toggle.active span { background: transparent; }
.nav-toggle.active span::before { top: 0; transform: rotate(45deg); background: #fff; }
.nav-toggle.active span::after { top: 0; transform: rotate(-45deg); background: #fff; }

/* Mobile nav overlay */
.mobile-nav {
    display: none;
    position: fixed;
    inset: 0;
    background: var(--gray-900);
    z-index: 999;
    padding: calc(var(--header-h) + var(--space-12)) var(--space-8) var(--space-8);
    flex-direction: column;
    gap: var(--space-6);
    opacity: 0;
    transition: opacity 0.3s ease;
}
.mobile-nav.open {
    display: flex;
    opacity: 1;
}
.mobile-nav a {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--gray-300);
    padding: var(--space-3) 0;
    border-bottom: 1px solid rgba(255,255,255,0.06);
    transition: color 0.2s, padding-left 0.2s;
}
.mobile-nav a:hover {
    color: var(--primary-400);
    padding-left: var(--space-3);
}

/* ══════════════════════════════════════════════════════════════════════════
   HERO (Index)
   ══════════════════════════════════════════════════════════════════════════ */

.hero {
    text-align: center;
    padding: var(--space-20) var(--space-6) var(--space-12);
    max-width: 640px;
    margin: 0 auto;
    position: relative;
}

.hero h1 {
    font-family: var(--font-display);
    font-size: clamp(2rem, 5vw, 2.8rem);
    font-weight: 800;
    color: var(--gray-900);
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: var(--space-5);
}

.hero-sub {
    font-size: 1.1rem;
    color: var(--gray-500);
    line-height: 1.65;
    max-width: 500px;
    margin: 0 auto var(--space-4);
}

.hero-byline {
    font-size: 0.85rem;
    color: var(--gray-400);
    font-family: var(--font-display);
    font-weight: 500;
}
.hero-byline a {
    color: var(--primary-700);
    font-weight: 700;
    border-bottom: 1px solid var(--primary-200);
}
.hero-byline a:hover { border-bottom-color: var(--primary-500); }

/* Decorative accent line */
.hero::after {
    content: "";
    display: block;
    width: 48px;
    height: 3px;
    background: var(--primary-500);
    border-radius: 2px;
    margin: var(--space-10) auto 0;
}

/* ══════════════════════════════════════════════════════════════════════════
   POSTS LIST (Index)
   ══════════════════════════════════════════════════════════════════════════ */

.posts-list {
    max-width: var(--max-width-wide);
    margin: 0 auto;
    padding: 0 var(--space-6) var(--space-24);
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--space-6);
}

/* Featured first card spans full width */
.posts-list .post-card:first-child {
    grid-column: 1 / -1;
    display: grid;
    grid-template-columns: 1.1fr 1fr;
    gap: var(--space-8);
    align-items: center;
}
.posts-list .post-card:first-child .post-card-thumb {
    aspect-ratio: 4 / 3;
    border-radius: var(--radius-lg);
    margin-bottom: 0;
}
.posts-list .post-card:first-child h2 {
    font-size: 1.6rem;
}

.post-card {
    display: block;
    background: #fff;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-card);
    transition: box-shadow 0.3s ease, transform 0.3s ease;
    color: inherit;
}
.post-card:hover {
    box-shadow: var(--shadow-card-hover);
    transform: translateY(-2px);
}

.post-card-thumb {
    width: 100%;
    aspect-ratio: 3 / 2;
    object-fit: cover;
    background: var(--gray-100);
    transition: transform 0.4s ease;
}
.post-card:hover .post-card-thumb {
    transform: scale(1.02);
}

.post-card article {
    padding: var(--space-5) var(--space-6) var(--space-6);
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.post-card-meta {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    font-family: var(--font-display);
}

.post-card time {
    font-size: 0.75rem;
    color: var(--gray-400);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.post-card-meta .reading-time {
    font-size: 0.75rem;
    color: var(--gray-400);
    font-weight: 500;
}
.post-card-meta .reading-time::before {
    content: "\00b7";
    margin-right: var(--space-3);
}

.post-card h2 {
    font-family: var(--font-display);
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--gray-900);
    line-height: 1.3;
    letter-spacing: -0.01em;
    transition: color 0.2s;
}
.post-card:hover h2 { color: var(--primary-800); }

.post-card p {
    color: var(--gray-500);
    font-size: 0.92rem;
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.read-more {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    font-family: var(--font-display);
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--primary-700);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-top: var(--space-2);
    transition: gap 0.2s ease, color 0.2s;
}
.post-card:hover .read-more {
    gap: var(--space-3);
    color: var(--primary-600);
}

.no-posts {
    grid-column: 1 / -1;
    text-align: center;
    color: var(--gray-400);
    padding: var(--space-16) 0;
    font-size: 1.1rem;
}

/* ══════════════════════════════════════════════════════════════════════════
   POST CONTENT (Article pages)
   ══════════════════════════════════════════════════════════════════════════ */

.post-content {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--space-10) var(--space-6) var(--space-24);
    flex: 1;
}

.post-meta {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    margin-bottom: var(--space-5);
    font-family: var(--font-display);
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--gray-400);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.post-meta .reading-time::before {
    content: "\00b7";
    margin-right: var(--space-4);
}

.post-content h1 {
    font-family: var(--font-display);
    font-size: clamp(1.8rem, 4vw, 2.4rem);
    font-weight: 800;
    color: var(--gray-900);
    line-height: 1.15;
    letter-spacing: -0.025em;
    margin-bottom: var(--space-8);
}

.post-content h2 {
    font-family: var(--font-display);
    font-size: 1.45rem;
    font-weight: 700;
    color: var(--gray-900);
    margin-top: var(--space-12);
    margin-bottom: var(--space-4);
    line-height: 1.25;
    letter-spacing: -0.015em;
    position: relative;
    padding-left: var(--space-5);
}
.post-content h2::before {
    content: "";
    position: absolute;
    left: 0;
    top: 4px;
    bottom: 4px;
    width: 3px;
    background: var(--primary-500);
    border-radius: 2px;
}

.post-content h3 {
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--gray-800);
    margin-top: var(--space-8);
    margin-bottom: var(--space-3);
    letter-spacing: -0.01em;
}

.post-content p {
    margin-bottom: var(--space-6);
    font-size: 1.06rem;
    color: var(--gray-700);
    line-height: 1.75;
}

.post-content a {
    color: var(--primary-700);
    font-weight: 500;
    text-decoration: underline;
    text-decoration-color: var(--primary-200);
    text-underline-offset: 3px;
    transition: text-decoration-color 0.2s;
}
.post-content a:hover {
    text-decoration-color: var(--primary-500);
}

.post-content ul, .post-content ol {
    margin-bottom: var(--space-6);
    padding-left: var(--space-6);
}
.post-content li {
    margin-bottom: var(--space-3);
    font-size: 1.06rem;
    color: var(--gray-700);
    line-height: 1.7;
}
.post-content li::marker {
    color: var(--primary-500);
}

.post-content strong { color: var(--gray-900); font-weight: 600; }

.post-content blockquote {
    border-left: 3px solid var(--primary-500);
    padding: var(--space-5) var(--space-6);
    margin: var(--space-8) 0;
    background: var(--primary-50);
    border-radius: 0 var(--radius) var(--radius) 0;
    font-style: italic;
    color: var(--gray-600);
}

/* ── Hero Image ── */

.hero-image {
    margin: 0 0 var(--space-8);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}
.hero-image img {
    width: 100%;
    height: auto;
    display: block;
    aspect-ratio: 1200 / 630;
    object-fit: cover;
    background: var(--gray-100);
}

/* ── Share Buttons ── */

.share-bar {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-4) 0;
    border-bottom: 1px solid var(--gray-200);
    margin-bottom: var(--space-8);
    flex-wrap: wrap;
}

.share-bar-bottom {
    border-bottom: none;
    border-top: 1px solid var(--gray-200);
    margin-top: var(--space-12);
    margin-bottom: 0;
    padding-top: var(--space-6);
}

.share-label {
    font-family: var(--font-display);
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--gray-400);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

.share-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-3);
    border-radius: 6px;
    font-family: var(--font-display);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--gray-500);
    background: var(--gray-100);
    border: none;
    transition: background 0.2s, color 0.2s, transform 0.15s;
    text-decoration: none;
}
.share-btn:hover { transform: translateY(-1px); }
.share-btn svg { flex-shrink: 0; }

.share-linkedin:hover { background: #0a66c2; color: #fff; }
.share-twitter:hover { background: var(--gray-900); color: #fff; }
.share-facebook:hover { background: #1877f2; color: #fff; }
.share-email:hover { background: var(--primary-700); color: #fff; }

/* ── Back to Top ── */

.back-to-top {
    position: fixed;
    bottom: var(--space-6);
    right: var(--space-6);
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--gray-900);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s, transform 0.3s;
    transform: translateY(8px);
    z-index: 900;
    border: 2px solid var(--primary-700);
}
.back-to-top.visible {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}
.back-to-top:hover {
    background: var(--primary-700);
    color: #fff;
    transform: translateY(-2px);
}
.back-to-top svg { width: 20px; height: 20px; }

/* ══════════════════════════════════════════════════════════════════════════
   FOOTER
   ══════════════════════════════════════════════════════════════════════════ */

.site-footer {
    background: var(--gray-900);
    color: var(--gray-400);
    padding: var(--space-16) var(--space-6) var(--space-8);
    margin-top: auto;
    position: relative;
}
.site-footer::before {
    content: "";
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 48px;
    height: 3px;
    background: var(--primary-700);
    border-radius: 2px;
    top: var(--space-8);
}

.footer-inner {
    max-width: var(--max-width-wide);
    margin: 0 auto;
    text-align: center;
    font-size: 0.88rem;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.footer-inner a {
    color: var(--primary-400);
    font-weight: 600;
}
.footer-inner a:hover { color: var(--primary-300); }

.copyright {
    font-size: 0.78rem;
    color: var(--gray-500);
    margin-top: var(--space-6);
    font-family: var(--font-display);
    font-weight: 500;
    letter-spacing: 0.02em;
}

/* ══════════════════════════════════════════════════════════════════════════
   404
   ══════════════════════════════════════════════════════════════════════════ */

.not-found {
    text-align: center;
    padding: var(--space-24) var(--space-6);
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--space-4);
}
.not-found h1 {
    font-family: var(--font-display);
    font-size: 5rem;
    font-weight: 800;
    color: var(--gray-200);
    letter-spacing: -0.04em;
}
.not-found p { color: var(--gray-500); font-size: 1.1rem; }
.not-found a {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--primary-700);
    border: 2px solid var(--primary-700);
    padding: var(--space-3) var(--space-6);
    border-radius: var(--radius);
    transition: background 0.2s, color 0.2s;
}
.not-found a:hover {
    background: var(--primary-700);
    color: #fff;
}

/* ══════════════════════════════════════════════════════════════════════════
   ANIMATIONS
   ══════════════════════════════════════════════════════════════════════════ */

@keyframes fadeUp {
    from { opacity: 0; transform: translateY(16px); }
    to { opacity: 1; transform: translateY(0); }
}

.hero h1 { animation: fadeUp 0.6s ease both; }
.hero-sub { animation: fadeUp 0.6s ease 0.1s both; }
.hero-byline { animation: fadeUp 0.6s ease 0.2s both; }

.post-card {
    animation: fadeUp 0.5s ease both;
}
.posts-list .post-card:nth-child(1) { animation-delay: 0.05s; }
.posts-list .post-card:nth-child(2) { animation-delay: 0.1s; }
.posts-list .post-card:nth-child(3) { animation-delay: 0.15s; }
.posts-list .post-card:nth-child(4) { animation-delay: 0.2s; }
.posts-list .post-card:nth-child(5) { animation-delay: 0.25s; }
.posts-list .post-card:nth-child(6) { animation-delay: 0.3s; }
.posts-list .post-card:nth-child(7) { animation-delay: 0.35s; }
.posts-list .post-card:nth-child(8) { animation-delay: 0.4s; }

/* ══════════════════════════════════════════════════════════════════════════
   RESPONSIVE
   ══════════════════════════════════════════════════════════════════════════ */

@media (max-width: 768px) {
    .nav-links { display: none; }
    .nav-toggle { display: block; }

    .hero { padding: var(--space-12) var(--space-5) var(--space-8); }

    .posts-list {
        grid-template-columns: 1fr;
        padding: 0 var(--space-4) var(--space-16);
        gap: var(--space-4);
    }
    .posts-list .post-card:first-child {
        grid-template-columns: 1fr;
    }
    .posts-list .post-card:first-child h2 {
        font-size: 1.3rem;
    }

    .post-content { padding: var(--space-6) var(--space-4) var(--space-16); }
    .post-content h1 { margin-bottom: var(--space-6); }
    .post-content h2 { font-size: 1.25rem; }

    .hero-image { border-radius: var(--radius); margin: 0 0 var(--space-6); }

    .share-bar { gap: var(--space-2); }
    .share-btn { padding: var(--space-2); font-size: 0; }
    .share-btn svg { width: 20px; height: 20px; }

    .site-footer { padding: var(--space-12) var(--space-4) var(--space-6); }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .posts-list {
        grid-template-columns: repeat(2, 1fr);
    }
    .posts-list .post-card:first-child {
        grid-template-columns: 1fr 1fr;
    }
}

@media (min-width: 1025px) {
    .posts-list {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* ── Print ── */
@media print {
    .site-header, .site-footer, .share-bar, .nav-toggle, .mobile-nav { display: none; }
    .post-content { max-width: 100%; padding: 0; }
    .post-content a { color: inherit; text-decoration: underline; }
    .post-content a::after { content: " (" attr(href) ")"; font-size: 0.8em; color: var(--gray-500); }
}