/* ============================================================
   TechPulse — Tech News Site
   Clean / modern / tech palette
   Display: Cabinet Grotesk | Body: Satoshi
   ============================================================ */

/* ---- DESIGN TOKENS ---------------------------------------- */
:root {
  --text-xs:   clamp(0.75rem,  0.7rem  + 0.25vw, 0.875rem);
  --text-sm:   clamp(0.875rem, 0.8rem  + 0.35vw, 1rem);
  --text-base: clamp(1rem,     0.95rem + 0.25vw, 1.125rem);
  --text-lg:   clamp(1.125rem, 1rem    + 0.75vw, 1.5rem);
  --text-xl:   clamp(1.5rem,   1.2rem  + 1.25vw, 2.25rem);
  --text-2xl:  clamp(2rem,     1.2rem  + 2.5vw,  3.5rem);
  --text-3xl:  clamp(2.5rem,   1rem    + 4vw,    5rem);

  --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;

  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1.25rem;
  --radius-full: 9999px;

  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  --content-default: 1100px;

  --font-display: 'Cabinet Grotesk', 'Helvetica Neue', sans-serif;
  --font-body:    'Satoshi', 'Inter', sans-serif;
}

/* ---- LIGHT MODE ------------------------------------------- */
:root, [data-theme="light"] {
  --color-bg:             #f4f6fb;
  --color-surface:        #ffffff;
  --color-surface-2:      #f8f9fd;
  --color-surface-offset: #eef0f8;
  --color-divider:        #e1e4ef;
  --color-border:         #d8dce8;

  --color-text:           #18192b;
  --color-text-muted:     #5c6077;
  --color-text-faint:     #a8abbe;
  --color-text-inverse:   #f4f6fb;

  --color-primary:        #3a5cf5;
  --color-primary-hover:  #2646d9;
  --color-primary-active: #1832b0;
  --color-primary-highlight: #dce3fd;

  --color-accent:         #0ea5e9;
  --color-accent-highlight: #e0f5fe;

  --shadow-sm: 0 1px 3px oklch(0.15 0.05 260 / 0.06);
  --shadow-md: 0 4px 14px oklch(0.15 0.05 260 / 0.09);
  --shadow-lg: 0 12px 36px oklch(0.15 0.05 260 / 0.13);
  --shadow-card-hover: 0 8px 28px oklch(0.15 0.05 260 / 0.14);
}

/* ---- DARK MODE -------------------------------------------- */
[data-theme="dark"] {
  --color-bg:             #0d0e18;
  --color-surface:        #131525;
  --color-surface-2:      #171929;
  --color-surface-offset: #1c1e30;
  --color-divider:        #22263a;
  --color-border:         #2c3050;

  --color-text:           #dde1f5;
  --color-text-muted:     #8388a8;
  --color-text-faint:     #454a6a;
  --color-text-inverse:   #0d0e18;

  --color-primary:        #6b8fff;
  --color-primary-hover:  #8ba5ff;
  --color-primary-active: #a8bcff;
  --color-primary-highlight: #1e2645;

  --color-accent:         #38bdf8;
  --color-accent-highlight: #0c2f42;

  --shadow-sm: 0 1px 3px oklch(0 0 0 / 0.25);
  --shadow-md: 0 4px 14px oklch(0 0 0 / 0.35);
  --shadow-lg: 0 12px 36px oklch(0 0 0 / 0.45);
  --shadow-card-hover: 0 8px 28px oklch(0 0 0 / 0.5);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg:             #0d0e18;
    --color-surface:        #131525;
    --color-surface-2:      #171929;
    --color-surface-offset: #1c1e30;
    --color-divider:        #22263a;
    --color-border:         #2c3050;
    --color-text:           #dde1f5;
    --color-text-muted:     #8388a8;
    --color-text-faint:     #454a6a;
    --color-text-inverse:   #0d0e18;
    --color-primary:        #6b8fff;
    --color-primary-hover:  #8ba5ff;
    --color-primary-active: #a8bcff;
    --color-primary-highlight: #1e2645;
    --color-accent:         #38bdf8;
    --color-accent-highlight: #0c2f42;
    --shadow-sm: 0 1px 3px oklch(0 0 0 / 0.25);
    --shadow-md: 0 4px 14px oklch(0 0 0 / 0.35);
    --shadow-lg: 0 12px 36px oklch(0 0 0 / 0.45);
    --shadow-card-hover: 0 8px 28px oklch(0 0 0 / 0.5);
  }
}

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

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  scroll-padding-top: var(--space-16);
}

body {
  min-height: 100dvh;
  line-height: 1.6;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color 300ms ease, color 300ms ease;
}

img, picture, video, canvas, svg { display: block; max-width: 100%; height: auto; }
h1, h2, h3 { text-wrap: balance; line-height: 1.2; font-family: var(--font-display); }
p, li { text-wrap: pretty; }

a, button, [role="button"] {
  transition: color var(--transition-interactive),
              background var(--transition-interactive),
              border-color var(--transition-interactive),
              box-shadow var(--transition-interactive),
              transform var(--transition-interactive),
              opacity var(--transition-interactive);
}

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* ---- LAYOUT ----------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--content-default);
  margin-inline: auto;
  padding-inline: clamp(var(--space-5), 5vw, var(--space-16));
}

/* ---- HEADER ----------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in oklab, var(--color-bg) 85%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-divider);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: var(--space-4);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-text);
}

.logo-bg { fill: var(--color-primary); }

.logo-text {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--color-text);
}

.header-right {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.date-badge {
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text-muted);
  letter-spacing: 0.02em;
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
  cursor: pointer;
  background: none;
  border: none;
}

.theme-toggle:hover {
  color: var(--color-primary);
  background: var(--color-primary-highlight);
}

/* ---- HERO ------------------------------------------------- */
.hero {
  padding-block: clamp(var(--space-12), 8vw, var(--space-20));
  border-bottom: 1px solid var(--color-divider);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 70% 60% at 60% 40%, 
    color-mix(in oklab, var(--color-primary) 8%, transparent),
    transparent 70%);
  pointer-events: none;
}

.hero-label {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-4);
}

.hero-title {
  font-family: var(--font-display);
  font-size: var(--text-3xl);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.05;
  color: var(--color-text);
  margin-bottom: var(--space-5);
}

.hero-accent {
  color: var(--color-primary);
}

.hero-sub {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  max-width: 52ch;
  line-height: 1.7;
}

/* ---- FEATURED STORY --------------------------------------- */
.featured-wrap {
  padding-block: var(--space-10);
}

.card--featured {
  display: block;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: clamp(var(--space-8), 4vw, var(--space-12));
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
}

.card--featured::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
}

.card--featured:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
  border-color: var(--color-primary);
}

.card-meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
  flex-wrap: wrap;
}

.tag {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
}

.tag--ai    { background: var(--color-primary-highlight); color: var(--color-primary); }
.tag--chips { background: color-mix(in oklab, #f59e0b 15%, var(--color-bg)); color: #b45309; }
.tag--dev   { background: color-mix(in oklab, #10b981 15%, var(--color-bg)); color: #047857; }
.tag--security { background: color-mix(in oklab, #ef4444 15%, var(--color-bg)); color: #b91c1c; }
.tag--defense  { background: color-mix(in oklab, #8b5cf6 15%, var(--color-bg)); color: #6d28d9; }

[data-theme="dark"] .tag--chips { background: color-mix(in oklab, #f59e0b 12%, transparent); color: #fbbf24; }
[data-theme="dark"] .tag--dev   { background: color-mix(in oklab, #10b981 12%, transparent); color: #34d399; }
[data-theme="dark"] .tag--security { background: color-mix(in oklab, #ef4444 12%, transparent); color: #f87171; }
[data-theme="dark"] .tag--defense  { background: color-mix(in oklab, #8b5cf6 12%, transparent); color: #a78bfa; }

.card-source {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  font-weight: 500;
}

.card-title--featured {
  font-size: clamp(1.5rem, 1.2rem + 1.5vw, 2.2rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin-bottom: var(--space-5);
  line-height: 1.15;
}

.card-body {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  line-height: 1.75;
  max-width: 80ch;
  margin-bottom: var(--space-6);
}

.read-link {
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.01em;
}

.card--featured:hover .read-link {
  color: var(--color-primary-hover);
}

/* ---- NEWS GRID -------------------------------------------- */
.news-grid-wrap {
  padding-bottom: clamp(var(--space-16), 8vw, var(--space-24));
}

.news-grid-wrap > h2 {
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin-bottom: var(--space-6);
  border-bottom: 1px solid var(--color-divider);
  padding-bottom: var(--space-4);
}

.news-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(320px, 100%), 1fr));
  gap: var(--space-6);
}

/* ---- CARD ------------------------------------------------- */
.card {
  display: flex;
  flex-direction: column;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-interactive),
              transform var(--transition-interactive),
              border-color var(--transition-interactive);
}

.card:not(.card--featured):hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-3px);
  border-color: var(--color-primary);
}

.card:not(.card--featured) .card-meta {
  margin-bottom: var(--space-4);
}

.card-title {
  font-size: var(--text-lg);
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--color-text);
  margin-bottom: var(--space-3);
  line-height: 1.3;
  flex-shrink: 0;
}

.card:not(.card--featured) .card-body {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.7;
  flex: 1;
  margin-bottom: var(--space-5);
}

.card:not(.card--featured) .read-link {
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.01em;
  margin-top: auto;
}

.card:not(.card--featured):hover .read-link {
  color: var(--color-primary-hover);
}

/* ---- FOOTER ----------------------------------------------- */
.site-footer {
  border-top: 1px solid var(--color-divider);
  padding-block: var(--space-10);
  background: var(--color-surface-2);
}

.footer-inner {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-8);
  flex-wrap: wrap;
}

.footer-logo {
  display: block;
  font-size: var(--text-lg);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.footer-note {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  max-width: 40ch;
}

.footer-right {
  display: flex;
  align-items: center;
}

.pplx-credit {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  text-decoration: none;
  font-weight: 500;
}

.pplx-credit:hover {
  color: var(--color-primary);
}

/* ---- RESPONSIVE ------------------------------------------- */
@media (max-width: 600px) {
  .date-badge { display: none; }

  .news-grid {
    grid-template-columns: 1fr;
  }

  .hero-title {
    font-size: clamp(2.2rem, 8vw, 3.5rem);
  }
}