/* ========================================
   PREMIUM DESIGN SYSTEM - APPLE-INSPIRED
   University of Michigan Blue Theme
   ======================================== */

/* Import modern font - Inter with full weight range */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap');

/* CSS Variables - Premium Design System */
:root {
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'SF Pro Display', system-ui, sans-serif;

    /* Colors - University of Michigan Blue Palette */
    --color-primary: #00274C;        /* UMich Blue - primary brand */
    --color-primary-light: #004B87;  /* Lighter Michigan Blue */
    --color-primary-dark: #001B34;   /* Darker Michigan Blue */
    --color-accent: #FFCB05;         /* UMich Maize - accent */
    --color-accent-dark: #FFB500;    /* Darker Maize */

    /* Supporting Colors */
    --color-success: #10B981;        /* Emerald green */
    --color-info: #3B82F6;           /* Bright blue */
    --color-black: #000000;          /* Pure black */
    --color-white: #FFFFFF;          /* Pure white */

    /* Backgrounds */
    --color-background: #FFFFFF;     /* Pure white */
    --color-background-alt: #F5F5F7; /* Apple-style subtle gray */
    --color-background-dark: #1D1D1F;/* Dark backgrounds */

    /* Borders */
    --color-border: #D2D2D7;         /* Light gray border */
    --color-border-dark: #424245;    /* Dark mode border */

    /* Text Colors */
    --color-text-primary: #1D1D1F;   /* Near-black - main text */
    --color-text-secondary: #6E6E73; /* Gray - secondary text */
    --color-text-tertiary: #86868B;  /* Light gray - tertiary */
    --color-text-inverse: #F5F5F7;   /* Light text on dark */

    /* Spacing - 8px grid system */
    --space-xs: 0.5rem;   /* 8px */
    --space-sm: 1rem;     /* 16px */
    --space-md: 1.5rem;   /* 24px */
    --space-lg: 2rem;     /* 32px */
    --space-xl: 3rem;     /* 48px */
    --space-2xl: 4rem;    /* 64px */
    --space-3xl: 6rem;    /* 96px */
    --space-4xl: 8rem;    /* 128px */

    /* Border radius */
    --radius-sm: 0.25rem;   /* 4px */
    --radius-md: 0.5rem;    /* 8px */
    --radius-lg: 0.875rem;  /* 14px */
    --radius-xl: 1.125rem;  /* 18px */
    --radius-2xl: 1.5rem;   /* 24px */
    --radius-full: 9999px;  /* Fully rounded */

    /* Shadows - Apple-style subtle */
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px 0 rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px 0 rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 12px 32px 0 rgba(0, 0, 0, 0.16);
    --shadow-2xl: 0 20px 48px 0 rgba(0, 0, 0, 0.20);

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Base reset and typography */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    background-color: var(--color-background);
    color: var(--color-text-primary);
    line-height: 1.5;
    font-size: 1rem;
    font-weight: 400;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

main {
    padding: 0;
    margin: 0;
    min-height: calc(100vh - 80px);
}

/* Typography Scale - Apple-inspired bold hierarchy */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.1;
    color: var(--color-text-primary);
    letter-spacing: -0.03em;
    margin-bottom: var(--space-md);
}

h1 {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 900;  /* Extra bold like Apple */
    line-height: 1.05;
    letter-spacing: -0.04em;
    word-spacing: 0.15em;
    margin-bottom: var(--space-lg);
}

h2 {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;  /* Bold headlines */
    line-height: 1.1;
    letter-spacing: -0.035em;
    margin-bottom: var(--space-md);
}

h3 {
    font-size: clamp(1.5rem, 4vw, 2.25rem);
    font-weight: 700;  /* Strong subheadings */
    line-height: 1.2;
    letter-spacing: -0.025em;
}

h4 {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    font-weight: 600;
    line-height: 1.3;
}

h5 {
    font-size: 1.125rem;
    font-weight: 600;
}

h6 {
    font-size: 1rem;
    font-weight: 600;
}

/* Body Text - Readable, not too light */
p {
    font-size: 1.0625rem;  /* 17px like Apple */
    line-height: 1.6;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-md);
    font-weight: 400;  /* Normal weight */
}

/* Lead text - larger intro paragraphs */
.lead {
    font-size: 1.25rem;
    line-height: 1.5;
    font-weight: 400;
    color: var(--color-text-secondary);
}

/* Links */
a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
    font-weight: 500;  /* Medium weight for links */
}

a:hover {
    color: var(--color-primary-light);
}

/* Strong and Bold */
strong, b {
    font-weight: 700;
    color: var(--color-text-primary);
}

/* Lists */
ul, ol {
    padding-left: 1.5rem;
    margin-bottom: var(--space-md);
}

li {
    margin-bottom: var(--space-xs);
    line-height: 1.6;
    color: var(--color-text-secondary);
}

/* Utility Classes */
.container {
    width: 100%;
    max-width: 1280px;
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--space-lg);
    padding-right: var(--space-lg);
}

.container-wide {
    max-width: 1440px;
}

.container-narrow {
    max-width: 980px;
}

.text-center {
    text-align: center;
}

.text-left {
    text-align: left;
}

.text-right {
    text-align: right;
}

/* Color utilities */
.text-primary {
    color: var(--color-primary);
}

.text-secondary {
    color: var(--color-text-secondary);
}

.text-white {
    color: var(--color-white);
}

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

.bg-alt {
    background-color: var(--color-background-alt);
}

/* Michigan Blue Gradient Text */
.gradient-text {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Accent (Maize) Gradient Text */
.gradient-accent {
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-dark) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Display text - extra large, extra bold */
.display-1 {
    font-size: clamp(3rem, 8vw, 6rem);
    font-weight: 900;
    line-height: 1;
    letter-spacing: -0.05em;
}

.display-2 {
    font-size: clamp(2.5rem, 7vw, 5rem);
    font-weight: 900;
    line-height: 1.05;
    letter-spacing: -0.045em;
}

/* Font weight utilities */
.font-normal { font-weight: 400; }
.font-medium { font-weight: 500; }
.font-semibold { font-weight: 600; }
.font-bold { font-weight: 700; }
.font-extrabold { font-weight: 800; }
.font-black { font-weight: 900; }

/* Spacing utilities */
.mt-xs { margin-top: var(--space-xs); }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }
.mt-2xl { margin-top: var(--space-2xl); }
.mt-3xl { margin-top: var(--space-3xl); }

.mb-xs { margin-bottom: var(--space-xs); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }
.mb-2xl { margin-bottom: var(--space-2xl); }
.mb-3xl { margin-bottom: var(--space-3xl); }

/* Selection styling */
::selection {
    background-color: var(--color-primary);
    color: var(--color-white);
}

::-moz-selection {
    background-color: var(--color-primary);
    color: var(--color-white);
}

/* Responsive */
@media (max-width: 1024px) {
    html {
        font-size: 15px;
    }

    .container {
        padding-left: var(--space-md);
        padding-right: var(--space-md);
    }
}

@media (max-width: 768px) {
    html {
        font-size: 14px;
    }

    .container {
        padding-left: var(--space-sm);
        padding-right: var(--space-sm);
    }

    h1 {
        letter-spacing: -0.03em;
    }

    h2 {
        letter-spacing: -0.025em;
    }

    p {
        font-size: 1rem;
    }
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Focus visible for accessibility */
*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}