/* Reset & Global Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Main Background - iOS 18 Dark Base */
    --bg-main: #1c1c1e;
    --bg-secondary: #2c2c2e;
    --background-dark: #1c1c1e;

    /* iOS 18 Liquid Glass - Primary Layers */
    --glass-ultra-light: rgba(255, 255, 255, 0.05);
    --glass-light: rgba(255, 255, 255, 0.08);
    --glass-medium: rgba(255, 255, 255, 0.12);
    --glass-strong: rgba(255, 255, 255, 0.16);

    /* Legacy aliases */
    --glass-lighter: rgba(255, 255, 255, 0.12);

    /* Borders - Subtle White Tint */
    --glass-border-subtle: rgba(255, 255, 255, 0.08);
    --glass-border: rgba(255, 255, 255, 0.16);
    --glass-border-strong: rgba(255, 255, 255, 0.24);

    /* Shadows - Multi-layer Depth */
    --glass-shadow: rgba(0, 0, 0, 0.3);
    --glass-shadow-strong: rgba(0, 0, 0, 0.5);
    --shadow-small: 0 4px 16px rgba(0, 0, 0, 0.2);
    --shadow-medium: 0 8px 32px rgba(0, 0, 0, 0.3);
    --shadow-large: 0 12px 48px rgba(0, 0, 0, 0.4);

    /* Backdrop Filters - iOS 18 Liquid Blur */
    --blur-light: blur(15px) saturate(180%);
    --blur-medium: blur(30px) saturate(180%) brightness(1.05);
    --blur-strong: blur(40px) saturate(200%) brightness(1.1);
    --blur-navbar: blur(40px) saturate(200%) brightness(1.15);

    /* Text Colors - iOS Typography */
    --text-primary: rgba(255, 255, 255, 0.95);
    --text-secondary: rgba(255, 255, 255, 0.65);
    --text-tertiary: rgba(255, 255, 255, 0.45);

    /* Accent Colors - Vibrant iOS Blue */
    --primary-color: #0A84FF;
    --accent-primary: #0A84FF;
    --accent-secondary: #64D2FF;
    --accent-gradient: linear-gradient(135deg, #0A84FF 0%, #64D2FF 100%);

    /* Semantic Colors */
    --success: #30D158;
    --error: #FF453A;
    --warning: #FFD60A;

    /* Border Radius Scale */
    --radius-sm: 10px;
    --radius-md: 16px;
    --radius-lg: 20px;
    --radius-xl: 24px;
    --radius-2xl: 28px;

    /* Transitions - iOS Spring */
    --transition-fast: cubic-bezier(0.4, 0.0, 0.2, 1) 0.15s;
    --transition-base: cubic-bezier(0.4, 0.0, 0.2, 1) 0.25s;
    --transition-slow: cubic-bezier(0.4, 0.0, 0.2, 1) 0.4s;
    --spring: cubic-bezier(0.32, 0.72, 0, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-main);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
}

#app {
    padding-top: 20px;
    padding-bottom: 100px;
    min-height: 100vh;
}

#page-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Common Page Header Style (DRY) */
.page-header {
    padding: 0 8px 12px 8px;
    text-align: center;
}

.page-header h1 {
    font-size: 28px;
    margin: 0;
    padding-top: 0;
    color: white;
    font-weight: 600;
}

/* iOS 18 Liquid Glass Card Base - Mobile Only */
.glass-card {
    background: var(--glass-light);
    backdrop-filter: var(--blur-medium);
    -webkit-backdrop-filter: var(--blur-medium);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    box-shadow:
        var(--shadow-medium),
        inset 0 1px 2px rgba(255, 255, 255, 0.1),
        inset 0 -1px 1px rgba(0, 0, 0, 0.05);
    transition: all var(--transition-fast);
    -webkit-tap-highlight-color: transparent;
}

/* Tactile feedback */
.glass-card:active {
    background: var(--glass-medium);
    border-color: var(--glass-border-strong);
    transform: scale(0.98);
    box-shadow:
        var(--shadow-small),
        inset 0 1px 2px rgba(255, 255, 255, 0.15),
        inset 0 -1px 1px rgba(0, 0, 0, 0.05);
}