/* =============================================================================
   TÍNH CHUẨN HUB - Premium Design System
   Central Hub for all Tinh Chuan tools
   ============================================================================= */

/* =========================================================================
   1. VARIABLES & RESET (skill.md v2.0 - Dark Mode Support)
   ========================================================================= */
:root {
    /* Light Mode (Default) */
    --bg-page: #f5f5f7;
    --bg-card: #ffffff;
    --text-primary: #1d1d1f;
    --text-secondary: #4b5563;
    --text-tertiary: #6b7280;
    --accent: #1d1d1f;
    --accent-hover: #000000;
    --border: #e5e5e5;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-hover: rgba(0, 0, 0, 0.15);
    --link-hover-bg: #f9f9fb;
}

[data-theme="dark"] {
    /* Dark Mode */
    --bg-page: #1d1d1f;
    --bg-card: #2c2c2e;
    --text-primary: #f5f5f7;
    --text-secondary: #d1d5db;
    --text-tertiary: #9ca3af;
    --accent: #ffffff;
    --accent-hover: #e5e5e5;
    --border: #3a3a3c;
    --shadow: rgba(0, 0, 0, 0.3);
    --shadow-hover: rgba(0, 0, 0, 0.4);
    --link-hover-bg: #3a3a3c;
}

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

html {
    -webkit-text-size-adjust: 100%;
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'SF Pro Text', 'Helvetica Neue', Arial, sans-serif;
    font-size: 16px;
    line-height: 1.5;
    color: var(--text-primary);
    background-color: var(--bg-page);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* =========================================================================
   2. LAYOUT
   ========================================================================= */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 60px 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* =========================================================================
   3. HERO SECTION
   ========================================================================= */
.hero {
    text-align: center;
    margin-bottom: 60px;
    animation: fadeIn 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.brand-badge {
    display: inline-block;
    padding: 6px 12px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 980px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 24px;
    box-shadow: 0 1px 2px var(--shadow);
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 16px;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.6;
}

/* =========================================================================
   4. TOOL GRID
   ========================================================================= */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 24px;
    margin-bottom: 80px;
}

.tool-card {
    background: var(--bg-card);
    border-radius: 20px;
    padding: 24px;
    text-decoration: none;
    border: 1px solid transparent;
    box-shadow: 0 4px 6px var(--shadow);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
    height: 100%;
}

.tool-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px var(--shadow-hover);
    border-color: var(--border);
}

.tool-icon {
    font-size: 2.5rem;
    margin-bottom: 10px;
    display: inline-block;
}

.tool-card h2 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.tool-card p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
    flex-grow: 1;
}

.tool-card .arrow {
    margin-top: 20px;
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--accent);
    display: flex;
    align-items: center;
    gap: 6px;
    opacity: 0;
    transform: translateX(-10px);
    transition: all 0.3s ease;
}

.tool-card:hover .arrow {
    opacity: 1;
    transform: translateX(0);
}

/* Featured Card Style */
.tool-card.featured {
    border: 1px solid var(--border);
    background: linear-gradient(145deg, var(--bg-card) 0%, var(--bg-page) 100%);
}

/* =========================================================================
   5. FOOTER
   ========================================================================= */
footer {
    margin-top: auto;
    text-align: center;
    padding-top: 40px;
    border-top: 1px solid var(--border);
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

footer a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
}

/* =========================================================================
   6. ANIMATIONS
   ========================================================================= */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .container {
        padding: 40px 20px;
    }
}

/* Disabled State */
.tool-card.disabled {
    opacity: 0.8;
    cursor: default;
    background: var(--bg-page);
    border: 1px dashed var(--border);
    box-shadow: none;
}

.tool-card.disabled:hover {
    transform: none;
    box-shadow: none;
    border-color: var(--border);
}

.status-badge {
    display: inline-block;
    margin-top: auto;
    padding: 4px 12px;
    background: var(--border);
    color: var(--text-secondary);
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 980px;
    align-self: flex-start;
}

/* =========================================================================
   Theme Toggle (skill.md v2.0)
   ========================================================================= */
.theme-toggle-wrapper {
    position: absolute;
    top: 20px;
    right: 20px;
    z-index: 100;
}

.theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 8px var(--shadow);
}

.theme-toggle:hover {
    background: var(--link-hover-bg);
    box-shadow: 0 4px 12px var(--shadow-hover);
    transform: translateY(-2px);
}

.theme-toggle:active {
    transform: translateY(0);
}

/* Icon visibility */
.sun-icon {
    display: block;
    color: var(--text-primary);
}

.moon-icon {
    display: none;
    color: var(--text-primary);
}

[data-theme="dark"] .sun-icon {
    display: none;
}

[data-theme="dark"] .moon-icon {
    display: block;
}