/* Grid System — Swiss Style Foundation */
.grid-container {
    display: grid;
    grid-template-columns: repeat(var(--grid-columns), 1fr);
    gap: calc(var(--space-unit) * 3);
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 calc(var(--space-unit) * 5);
    position: relative;
}

/* Running Header Rail — fixed editorial masthead */
.running-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 32px;
    z-index: 90;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 calc(var(--space-unit) * 5);
    font-family: var(--font-mono);
    font-size: 0.625rem;
    text-transform: uppercase;
    letter-spacing: 0.18em;
    color: var(--color-text-muted);
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    pointer-events: none;
}

.running-header .rh-dot {
    display: inline-block;
    width: 7px;
    height: 7px;
    background: var(--color-accent);
    border-radius: 50%;
    margin-right: calc(var(--space-unit));
    vertical-align: middle;
    animation: pulse-dot 2.4s ease-in-out infinite;
}

@keyframes pulse-dot {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.25;
    }
}

@media (max-width: 768px) {
    .running-header {
        display: none;
    }

    .nav {
        top: 0;
    }

    .grid-container {
        padding: 0 calc(var(--space-unit) * 3);
    }
}

/* Decorative Grid Lines */
.grid-lines {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
    z-index: 0;
    opacity: 0.5;
    mix-blend-mode: multiply;
}

@media (prefers-color-scheme: dark) {
    .grid-lines {
        mix-blend-mode: screen;
    }
}

.grid-line-v {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 1px;
    background: var(--color-grid);
}

/* Grid Columns */
.span-12 {
    grid-column: span 12;
}

.span-8 {
    grid-column: span 8;
}

.span-6 {
    grid-column: span 6;
}

.span-4 {
    grid-column: span 4;
}

.span-3 {
    grid-column: span 3;
}

.span-2 {
    grid-column: span 2;
}

.offset-4 {
    grid-column-start: 5;
}

.offset-6 {
    grid-column-start: 7;
}

.offset-8 {
    grid-column-start: 9;
}

/* Spacing */
.py-xl {
    padding-top: calc(var(--space-unit) * 18);
    padding-bottom: calc(var(--space-unit) * 18);
}

.py-lg {
    padding-top: calc(var(--space-unit) * 14);
    padding-bottom: calc(var(--space-unit) * 14);
}

.py-md {
    padding-top: calc(var(--space-unit) * 8);
    padding-bottom: calc(var(--space-unit) * 8);
}

.py-sm {
    padding-top: calc(var(--space-unit) * 4);
    padding-bottom: calc(var(--space-unit) * 4);
}

.mb-xl {
    margin-bottom: calc(var(--space-unit) * 12);
}

.mb-lg {
    margin-bottom: calc(var(--space-unit) * 8);
}

.mb-md {
    margin-bottom: calc(var(--space-unit) * 4);
}

.mb-sm {
    margin-bottom: calc(var(--space-unit) * 2);
}

/* Theme Grid */
.theme-grid {
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    gap: 1px;
    background: var(--color-border);
    width: calc(100% - calc(var(--space-unit) * 10));
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1px;
}

/* Footer Grid */
.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: calc(var(--space-unit) * 6);
}

/* Responsive Breakpoints */
@media (max-width: 768px) {
    .grid-container {
        grid-template-columns: 1fr;
        gap: calc(var(--space-unit) * 2);
    }

    .span-12,
    .span-8,
    .span-6,
    .span-4,
    .span-3,
    .span-2 {
        grid-column: span 1;
    }

    .offset-4,
    .offset-6,
    .offset-8 {
        grid-column-start: auto;
    }

    .theme-grid {
        grid-template-columns: 1fr;
        width: calc(100% - calc(var(--space-unit) * 6));
        padding: 1px;
    }

    .theme-card {
        grid-column: span 12;
    }

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

@media (max-width: 1024px) {
    .grid-container {
        padding: 0 calc(var(--space-unit) * 3);
    }
}

@media (min-width: 1440px) {
    :root {
        --max-width: 1600px;
    }

    .grid-container {
        padding: 0 calc(var(--space-unit) * 6);
    }

    .running-header {
        padding: calc(var(--space-unit) * 1.5) calc(var(--space-unit) * 6);
    }

    .t-display {
        font-size: clamp(6rem, 15vw, 17rem);
    }

    .t-headline {
        font-size: clamp(3rem, 5vw, 6rem);
    }

    .t-title {
        font-size: clamp(1.6rem, 2vw, 2.25rem);
    }

    .t-body {
        font-size: 1.125rem;
    }

    .py-xl {
        padding-top: calc(var(--space-unit) * 22);
        padding-bottom: calc(var(--space-unit) * 22);
    }

    .py-lg {
        padding-top: calc(var(--space-unit) * 18);
        padding-bottom: calc(var(--space-unit) * 18);
    }

    .mb-xl {
        margin-bottom: calc(var(--space-unit) * 16);
    }
}