/* ========== MATERIAL DESIGN VARIABLES ========== */
:root {
    /* Color Palette - Google Material */
    --md-primary: #1A73E8;
    --md-primary-dark: #1557B0;
    --md-primary-light: #4285F4;
    --md-surface: #FFFFFF;
    --md-background: #F8F9FA;
    --md-on-surface: #202124;
    --md-on-surface-variant: #5F6368;
    --md-outline: #DADCE0;
    --md-success: #1E8E3E;
    --md-warning: #F9AB00;
    --md-error: #D93025;
    
    /* Elevation Shadows - Material Design */
    --md-elevation-0: none;
    --md-elevation-1: 0 1px 2px 0 rgba(60,64,67,.3), 0 1px 3px 1px rgba(60,64,67,.15);
    --md-elevation-2: 0 1px 2px 0 rgba(60,64,67,.3), 0 2px 6px 2px rgba(60,64,67,.15);
    --md-elevation-3: 0 4px 8px 3px rgba(60,64,67,.15), 0 1px 3px rgba(60,64,67,.3);
    --md-elevation-4: 0 6px 10px 4px rgba(60,64,67,.15), 0 2px 3px rgba(60,64,67,.3);
    
    /* Spacing System */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 9999px;
    
    /* Transitions - Material Motion */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Typography */
    --font-sans: 'Inter', 'Google Sans', -apple-system, BlinkMacSystemFont, sans-serif;
}

/* ========== GLOBAL RESET & FOUNDATION ========== */
* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body, html, [class*="css"] {
    font-family: var(--font-sans);
    color: var(--md-on-surface);
    background-color: var(--md-background);
}

/* ========== BUTTONS - MATERIAL DESIGN ========== */
.stButton > button {
    background: var(--md-primary) !important;
    color: white !important;
    border: none !important;
    border-radius: var(--radius-md) !important;
    padding: 10px 24px !important;
    font-weight: 500 !important;
    font-size: 14px !important;
    letter-spacing: 0.25px !important;
    box-shadow: var(--md-elevation-2) !important;
    transition: all var(--transition-fast) !important;
    min-height: 44px !important;
}

.stButton > button:hover {
    background: var(--md-primary-dark) !important;
    box-shadow: var(--md-elevation-3) !important;
    transform: translateY(-1px);
}

.stButton > button:active {
    transform: translateY(0);
    box-shadow: var(--md-elevation-1) !important;
}

/* Touch-friendly on mobile */
@media (max-width: 768px) {
    .stButton > button {
        min-height: 48px !important;
        padding: 12px 24px !important;
        font-size: 16px !important;
    }
    
    body {
        font-size: 16px; /* Prevents iOS zoom */
    }
}

/* ========== SMOOTH ANIMATIONS ========== */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideInRight {
    from {
        transform: translateX(20px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* ========== SCROLLBAR STYLING ========== */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--md-background);
}

::-webkit-scrollbar-thumb {
    background: var(--md-outline);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--md-on-surface-variant);
}

/* ========== RESPONSIVE TYPOGRAPHY ========== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 500;
    color: var(--md-on-surface);
}

h1 { font-size: 32px; line-height: 40px; }
h2 { font-size: 24px; line-height: 32px; }
h3 { font-size: 20px; line-height: 28px; }

@media (max-width: 768px) {
    h1 { font-size: 24px; line-height: 32px; }
    h2 { font-size: 20px; line-height: 28px; }
    h3 { font-size: 18px; line-height: 24px; }
}

/* ========== TRANSITIONS FOR INTERACTIVE ELEMENTS ========== */
button, a, input, textarea, select, [role="button"] {
    transition: all var(--transition-fast);
}

/* ========== MOBILE TAP TARGETS ========== */
@media (max-width: 768px) {
    button, a, [role="button"] {
        min-height: 44px;
        min-width: 44px;
    }
}

/* ========== ACCESSIBILITY ========== */
*:focus-visible {
    outline: 2px solid var(--md-primary);
    outline-offset: 2px;
}