/*
 * File: common.css
 * Description: Shared styles, CSS variables, reset, and components.
 */

/* ========================================
   CSS RESET
   ======================================== */

*, *::before, *::after {
    box-sizing: border-box;
}

body, h1, h2, h3, h4, h5, h6, p, ul, ol {
    margin: 0;
}

ul, ol {
    padding: 0;
    list-style: none;
}

a {
    text-decoration: none;
    color: var(--accent-link);
}

a:hover {
    text-decoration: underline;
}

/* ========================================
   DESIGN TOKENS (CSS VARIABLES)
   ======================================== */

:root {
    /* Spacing */
    --space-minimal: 5px;
    --space-small: 10px;
    --space-medium: 15px;
    --space-large: 20px;

    /* Border & Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-pill: 999px;

    /* Typography */
    --font-xs: 12px;
    --font-sm: 14px;
    --font-base: 16px;
    --font-md: 18px;
    --font-lg: 22px;
    --letter-spacing-sm: 0.5px;

    /* Layout */
    --content-max-width: 900px;
    --content-padding: 20px;
    --content-padding-mobile: 12px;

    /* Buttons */
    --button-padding-block: 10px;
    --button-padding-inline: 20px;

    /* Floating elements */
    --floating-button-size: 44px;
    --floating-button-offset: 20px;
    --overlay-padding-top: 90px;

    /* Transitions */
    --transition-fast: 0.15s;
    --transition-normal: 0.2s;
    --transition-slow: 0.3s;
    --ease-out: cubic-bezier(0.25, 0, 0.2, 1);

    /* Light mode colors */
    --surface-muted: #f8f8f8;
    --card-bg: #fff;
    --panel-bg: #f9f9f9;
    --panel-alt-bg: #f1f1f1;
    --header-bg: #f0f0f0;
    --card-border: #e0e0e0;
    --panel-border: #ddd;
    --frame-border: #ccc;
    --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
    --text-strong: #333;
    --muted-text: #555;
    --text-inverse: #000;
    --accent-primary: #007BFF;
    --accent-link: #0b63ce;
    --accent-hover: #eee;
    --badge-success-bg: #d4edda;
    --badge-success-text: #155724;
    --badge-danger-bg: #f8d7da;
    --badge-danger-text: #721c24;
    --mark-bg: yellow;
    --mark-text: #000;
}

@media (prefers-color-scheme: dark) {
    :root {
        --surface-muted: #1a1a1a;
        --card-bg: #1e1e1e;
        --panel-bg: #252525;
        --panel-alt-bg: #2a2a2a;
        --header-bg: #252525;
        --card-border: #3a3a3a;
        --panel-border: #404040;
        --frame-border: #4a4a4a;
        --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
        --text-strong: #e0e0e0;
        --muted-text: #b0b0b0;
        --text-inverse: #fff;
        --accent-primary: #4a9eff;
        --accent-link: #5ba3ff;
        --accent-hover: #2a2a2a;
        --badge-success-bg: #1a3a2a;
        --badge-success-text: #7dcea0;
        --badge-danger-bg: #3a1a1a;
        --badge-danger-text: #e07070;
        --mark-bg: #665500;
        --mark-text: #ffeb3b;
    }
}

/* ========================================
   BASE STYLES
   ======================================== */

body {
    font-family: 'Roboto', Arial, sans-serif;
    font-size: var(--font-base);
    line-height: 1.5;
    color: var(--text-strong);
    background-color: var(--surface-muted);
    -webkit-font-smoothing: antialiased;
}

mark {
    background-color: var(--mark-bg);
    color: var(--mark-text);
    border-radius: 2px;
    padding: 0 2px;
}

h1, h2, h3 {
    font-weight: 600;
    line-height: 1.3;
}

h1 { font-size: var(--font-lg); }
h2 { font-size: var(--font-md); }

/* ========================================
   COMPONENTS
   ======================================== */

/* Card */
.card {
    padding: var(--space-large);
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-md);
    box-shadow: var(--card-shadow);
}

.card-small {
    padding: var(--space-medium);
    background: var(--panel-bg);
    border: 1px solid var(--panel-border);
    border-radius: var(--radius-sm);
}

/* Buttons */
button, .btn {
    padding: var(--button-padding-block) var(--button-padding-inline);
    background: var(--panel-alt-bg);
    border: 1px solid var(--frame-border);
    border-radius: var(--radius-sm);
    color: var(--text-strong);
    font-family: inherit;
    font-size: var(--font-sm);
    cursor: pointer;
    transition: background-color var(--transition-fast),
                border-color var(--transition-fast);
}

button:hover, .btn:hover {
    background: var(--panel-bg);
}

/* Inputs */
input[type="text"],
input[type="url"],
input[type="password"],
input[type="email"],
input[type="file"],
textarea,
select {
    width: 100%;
    padding: var(--space-small) var(--space-medium);
    background: var(--card-bg);
    border: 1px solid var(--frame-border);
    border-radius: var(--radius-sm);
    color: var(--text-strong);
    font-family: inherit;
    font-size: var(--font-base);
    transition: border-color var(--transition-fast);
}

input::placeholder,
textarea::placeholder {
    color: var(--muted-text);
}

input:focus,
textarea:focus {
    outline: none;
    border-color: var(--accent-primary);
}

label {
    display: block;
    font-size: var(--font-sm);
    font-weight: 500;
    color: var(--muted-text);
    margin-bottom: var(--space-minimal);
}

/* Screen reader only */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ========================================
   FLOATING OVERLAY
   ======================================== */

.floating-overlay {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: flex;
    align-items: flex-start;
    justify-content: center;
    padding-top: var(--overlay-padding-top);
    background: rgba(0, 0, 0, 0.5);
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-slow) var(--ease-out),
                visibility var(--transition-slow);
}

.floating-overlay.is-visible {
    opacity: 1;
    visibility: visible;
}

.floating-message {
    max-width: 520px;
    width: 90%;
    padding: var(--space-large);
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: var(--radius-md);
    box-shadow: var(--card-shadow);
    display: flex;
    flex-direction: column;
    gap: var(--space-medium);
}

.floating-message p {
    font-size: var(--font-md);
    text-align: center;
}

/* ========================================
   SCROLLBARS
   ======================================== */

* {
    scrollbar-color: var(--panel-border) var(--panel-bg);
}

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

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

::-webkit-scrollbar-thumb {
    background: var(--panel-border);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--muted-text);
}

/* ========================================
   ANIMATIONS
   ======================================== */

@keyframes fadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}

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