:root {
    --primary-color: #007BFF;
    --primary-light: #4DA3FF;
    --primary-dark: #0056b3;
    --primary-gradient: linear-gradient(135deg, #007BFF 0%, #4DA3FF 100%);

    --secondary-color: #4A90E2;
    --accent-color: #FF6B6B;
    --warning-color: #F39C12;
    --warning-gradient: linear-gradient(135deg, #F39C12 0%, #F1C40F 100%);
    --accent-gradient: linear-gradient(135deg, #FF6B6B 0%, #FF4757 100%);
    --success-color: #27AE60;
    --info-color: #3498DB;

    --text-primary: #2C3E50;
    --text-secondary: #7F8C8D;
    --text-light: #BDC3C7;
    --background: #FFFFFF;
    --background-alt: #F8F9FA;
    --background-dark: #ECF0F1;
    --border-color: #E1E8ED;
    --shadow-light: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-heavy: 0 10px 25px rgba(0, 0, 0, 0.15);

    --dark-bg: #1A1A2E;
    --dark-bg-alt: #16213E;
    --dark-text: #EAEAEA;
    --dark-text-secondary: #B0B0B0;
    --dark-border: #0F3460;

    --font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, "sans-serif";
    --font-mono: "Consolas", "Menlo", "Monaco", "Liberation Mono", "Courier New", monospace;

    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    --bounce: cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

[data-theme="dark"] {
    --background: var(--dark-bg);
    --background-alt: var(--dark-bg-alt);
    --background-dark: var(--dark-border);
    --text-primary: var(--dark-text);
    --text-secondary: var(--dark-text-secondary);
    --border-color: var(--dark-border);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

button,
#search-input,
#auth-password-input {
    font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, "sans-serif";
}

#particles-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: linear-gradient(45deg, #f0f9ff 0%, #e0f2fe 50%, #f0f9ff 100%);
    background-size: 400% 400%;
    animation: gradientShift 8s ease infinite;
}

#particles-background::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image:
        radial-gradient(circle at 20% 20%, rgba(0, 123, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(77, 163, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 60%, rgba(0, 86, 179, 0.05) 0%, transparent 50%);
    animation: float 6s ease-in-out infinite;
}

[data-theme="dark"] #particles-background {
    background: var(--dark-bg);
    animation: none;
}

[data-theme="dark"] #particles-background::before {
    background-image:
        radial-gradient(circle at 20% 20%, rgba(15, 52, 96, 0.2) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(22, 33, 62, 0.2) 0%, transparent 50%),
        radial-gradient(circle at 40% 60%, rgba(26, 26, 46, 0.1) 0%, transparent 50%);
}

::-webkit-scrollbar {
    width: 8px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-dark);
}

::selection {
    background: rgba(46, 139, 87, 0.3);
    color: var(--text-primary);
}

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