/* ==========================================================================
   theme.css — Global design tokens & base styles
   --------------------------------------------------------------------------
   Single source of truth for color, typography, spacing, radii, and depth.
   Design system synthesis:
     - Beaird & George: mathematical scale, analogous green color harmony
       with tinted neutrals; consistent proportional rhythm.
     - Santa Maria: serif display (Fraunces) paired with a humanist sans
       (DM Sans); fluid modular type scale; 60–75ch reading measure.
     - Wathan & Schoger: muted green-tinted grays instead of pure black,
       soft layered shadows instead of heavy borders, whitespace and
       font-weight for hierarchy.

   Legacy variable names (--primary-green, --card-shadow, ...) are aliased
   to the new tokens so existing component CSS keeps working unchanged.
   ========================================================================== */

:root {
    /* ----- Color: brand ------------------------------------------------- */
    --color-primary: #2D6A4F;        /* deep brand green */
    --color-primary-strong: #1F4D38; /* pressed / emphasis */
    --color-primary-soft: #52B788;   /* secondary green, accents */
    --color-primary-tint: rgba(45, 106, 79, 0.06);  /* subtle fills */
    --color-accent: #1976D2;         /* rare informational accent */

    /* ----- Color: green-tinted neutrals (no pure black or default gray) - */
    --color-bg: #F4F7F5;             /* page background */
    --color-bg-elevated: #FBFCFB;    /* gradient start, raised regions */
    --color-surface: #FFFFFF;        /* cards */
    --color-text: #22332B;           /* primary copy */
    --color-text-secondary: #5B6962; /* supporting copy, metadata */
    --color-text-muted: #75847B;     /* captions, fine print */
    --color-border: #E2E8E4;         /* hairlines, dividers */

    /* ----- Typography ---------------------------------------------------- */
    --font-sans: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-serif: 'Fraunces', Georgia, 'Times New Roman', serif;

    /* Fluid modular scale (~1.2 minor third, expanding slightly on desktop) */
    --text-xs: 0.8rem;
    --text-sm: 0.9rem;
    --text-base: 1rem;
    --text-lg: clamp(1.1rem, 1.05rem + 0.25vw, 1.2rem);
    --text-xl: clamp(1.25rem, 1.15rem + 0.5vw, 1.45rem);
    --text-2xl: clamp(1.5rem, 1.32rem + 0.9vw, 1.85rem);
    --text-3xl: clamp(1.9rem, 1.62rem + 1.4vw, 2.4rem);
    --text-4xl: clamp(2.25rem, 1.87rem + 1.9vw, 2.9rem);

    --leading-tight: 1.2;   /* display headings */
    --leading-snug: 1.45;   /* subheads, dense UI */
    --leading-body: 1.7;    /* long-form copy */
    --measure: 70ch;        /* 60–75 character reading width */

    /* ----- Spacing: strict 4px base grid --------------------------------- */
    --space-1: 0.25rem;   /*  4px */
    --space-2: 0.5rem;    /*  8px */
    --space-3: 0.75rem;   /* 12px */
    --space-4: 1rem;      /* 16px */
    --space-6: 1.5rem;    /* 24px */
    --space-8: 2rem;      /* 32px */
    --space-10: 2.5rem;   /* 40px */
    --space-12: 3rem;     /* 48px */
    --space-16: 4rem;     /* 64px */

    /* ----- Radii ---------------------------------------------------------- */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 12px;

    /* ----- Depth: soft layered shadows over heavy borders ----------------- */
    --shadow-sm: 0 1px 3px rgba(34, 51, 43, 0.05), 0 4px 12px rgba(34, 51, 43, 0.06);
    --shadow-md: 0 2px 6px rgba(34, 51, 43, 0.06), 0 8px 20px rgba(34, 51, 43, 0.08);
    --shadow-lg: 0 6px 14px rgba(34, 51, 43, 0.08), 0 14px 32px rgba(34, 51, 43, 0.12);

    /* ----- Legacy aliases (consumed by existing component CSS) ------------ */
    --primary-green: var(--color-primary);
    --light-green: var(--color-primary-soft);
    --accent-blue: var(--color-accent);
    --light-gray: var(--color-bg);
    --medium-gray: var(--color-border);
    --dark-gray: var(--color-text);
    --white: var(--color-surface);
    --bg-primary: var(--color-bg-elevated);
    --bg-secondary: var(--color-bg);
    --text-primary: var(--color-text);
    --text-secondary: var(--color-text-secondary);
    --border-color: var(--color-border);
    --card-shadow: var(--shadow-sm);
    --hover-shadow: var(--shadow-lg);
    --objective-bg: var(--color-primary-tint);
}

/* ----- Dark theme: same token names, inverted values ----------------------- */
[data-theme="dark"] {
    --color-primary: #52B788;
    --color-primary-strong: #74C9A1;
    --color-primary-soft: #2D6A4F;
    --color-primary-tint: rgba(82, 183, 136, 0.1);

    --color-bg: #163327;
    --color-bg-elevated: #1A3D2E;
    --color-surface: #1F4433;
    --color-text: #F2F5F3;
    --color-text-secondary: #C9D4CE;
    --color-text-muted: #9FAFA6;
    --color-border: #3D5A4A;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.25), 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 2px 6px rgba(0, 0, 0, 0.3), 0 8px 20px rgba(0, 0, 0, 0.35);
    --shadow-lg: 0 6px 14px rgba(0, 0, 0, 0.35), 0 14px 32px rgba(0, 0, 0, 0.4);

    /* Legacy aliases that swap in dark mode */
    --primary-green: var(--color-primary);
    --light-green: var(--color-primary-soft);
    --light-gray: var(--color-bg);
    --medium-gray: var(--color-border);
    --dark-gray: var(--color-text);
    --white: var(--color-surface);
    --bg-primary: var(--color-bg-elevated);
    --bg-secondary: var(--color-bg);
}

/* ==========================================================================
   Base element styles
   ========================================================================== */

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: var(--leading-body);
    color: var(--color-text);
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

/* Serif display voice for major headings; sans + weight for minor levels */
h1, h2, h3 {
    font-family: var(--font-serif);
    font-weight: 600;
    line-height: var(--leading-tight);
    letter-spacing: -0.015em;
}

h4, h5, h6 {
    font-family: var(--font-sans);
    font-weight: 700;
    line-height: var(--leading-snug);
    letter-spacing: -0.01em;
}

/* Reading measure: cap long-form copy at 60–75 characters */
.card p,
.intro-text p,
.timeline-item p,
.media-item p,
.faq-item .answer,
.manuscript-item .objective,
.manuscript-item .coauthors {
    max-width: var(--measure);
}

::selection {
    background: rgba(82, 183, 136, 0.3);
}

a:focus-visible,
button:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
    border-radius: 2px;
}

/* ==========================================================================
   Layout utilities (4px-grid container system)
   ========================================================================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-12) var(--space-8);
}

.container--narrow {
    max-width: 800px;
}

.container--flush {
    padding-top: 0;
    padding-bottom: 0;
}

@media (max-width: 768px) {
    .container {
        padding: var(--space-8) var(--space-4);
    }
}

/* ==========================================================================
   Motion preferences
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }

    html {
        scroll-behavior: auto;
    }
}