/* ============================================
   THEME.CSS - Shared Theme Styles
   Yeyang Liu Portfolio
   ============================================ */

/* ===================== CSS Variables ===================== */
:root {
    --bg-primary: #f0f9ff;
    --bg-secondary: #e0f2fe;
    --bg-card: #ffffff;
    --text-primary: #1e3a5f;
    --text-secondary: #1e40af;
    --accent: #2563eb;
    --accent-dim: rgba(37, 99, 235, 0.15);
    --accent-glow: rgba(37, 99, 235, 0.35);
    --border: rgba(37, 99, 235, 0.2);
    --gradient-1: linear-gradient(135deg, #2563eb 0%, #0ea5e9 50%, #06b6d4 100%);
    --shadow: 0 4px 20px rgba(30, 58, 95, 0.15);
    --glass-bg: rgba(255, 255, 255, 0.25);
    --glass-border: rgba(255, 255, 255, 0.4);
}

[data-theme="night"] {
    --bg-primary: #09090b;
    --bg-secondary: #18181b;
    --bg-card: #27272a;
    --text-primary: #fafafa;
    --text-secondary: #d4d4d8;
    --accent: #fbbf24;
    --accent-dim: rgba(251, 191, 36, 0.15);
    --accent-glow: rgba(251, 191, 36, 0.4);
    --border: rgba(251, 191, 36, 0.2);
    --gradient-1: linear-gradient(135deg, #fbbf24 0%, #f59e0b 50%, #d97706 100%);
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
    --glass-bg: rgba(255, 255, 255, 0.06);
    --glass-border: rgba(255, 255, 255, 0.1);
}

/* ===================== Base Reset ===================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    cursor: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 100 100"><text y="75" font-size="75">🐱</text></svg>') 16 16, auto;
}

a, button, .theme-toggle, .tech-tag, .skill-tag, .project-card, .contact-link, .avatar-container {
    cursor: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 100 100"><text y="75" font-size="75">😺</text></svg>') 16 16, pointer;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Outfit', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
    min-width: 320px;
}

/* ===================== Background Patterns ===================== */
.bg-pattern {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    opacity: 1;
    background-image: 
        radial-gradient(ellipse at 10% 90%, rgba(14, 165, 233, 0.3) 0%, transparent 50%),
        radial-gradient(ellipse at 90% 10%, rgba(6, 182, 212, 0.25) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 50%, rgba(34, 211, 238, 0.15) 0%, transparent 60%);
}

[data-theme="night"] .bg-pattern {
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(251, 191, 36, 0.12) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(245, 158, 11, 0.08) 0%, transparent 50%);
}

.grid-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    background-image: 
        linear-gradient(var(--border) 1px, transparent 1px),
        linear-gradient(90deg, var(--border) 1px, transparent 1px);
    background-size: 60px 60px;
    opacity: 0.5;
}

[data-theme="night"] .grid-overlay {
    opacity: 0.3;
}

/* ===================== Navigation ===================== */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    padding: 1.5rem 3rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 100;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    box-shadow: var(--shadow);
}

.logo {
    font-weight: 700;
    font-size: 1.3rem;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.1);
}

.logo:active {
    transform: scale(0.95);
}

.nav-links {
    display: flex;
    gap: 2.5rem;
    list-style: none;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 400;
    transition: color 0.3s ease;
    position: relative;
}

.nav-links a:hover {
    color: var(--accent);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: width 0.3s ease;
}

.nav-links a:hover::after {
    width: 100%;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.back-link {
    color: var(--text-secondary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: color 0.3s ease;
}

.back-link:hover {
    color: var(--accent);
}

/* ===================== Theme Toggle ===================== */
.theme-toggle {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: 50px;
    padding: 0.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
}

.theme-toggle:hover {
    border-color: var(--accent);
}

.theme-toggle .icon {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.theme-toggle .icon.active {
    background: var(--gradient-1);
}

.theme-toggle .day-icon {
    color: var(--text-secondary);
}

.theme-toggle .night-icon {
    color: var(--text-secondary);
}

[data-theme="night"] .theme-toggle .night-icon {
    color: var(--bg-primary);
}

:root .theme-toggle .day-icon {
    color: var(--bg-primary);
}

[data-theme="night"] .theme-toggle .day-icon {
    color: var(--text-secondary);
}

:root:not([data-theme="night"]) .theme-toggle .day-icon.active {
    background: var(--gradient-1);
}

[data-theme="night"] .theme-toggle .night-icon.active {
    background: var(--gradient-1);
}

/* ===================== Main Content ===================== */
main {
    position: relative;
    z-index: 1;
    width: 100%;
}

section {
    padding: 6rem 3rem;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
    box-sizing: border-box;
}

/* ===================== Buttons ===================== */
.btn {
    padding: 0.9rem 2rem;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    font-family: inherit;
}

.btn-primary {
    background: var(--gradient-1);
    color: var(--bg-primary);
    border: none;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px var(--accent-glow);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    border-color: var(--accent);
    color: var(--accent);
}

/* ===================== Section Headers ===================== */
.section-header {
    margin-bottom: 3rem;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.section-header h2 span {
    color: var(--accent);
}

.section-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* ===================== Cards (Glass Effect) ===================== */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 2rem;
    transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    box-shadow: var(--shadow);
}

.glass-card:hover {
    border-color: var(--accent);
    transform: translateY(-8px) rotateX(2deg);
    box-shadow: 0 20px 40px var(--accent-glow);
}

/* ===================== Badge ===================== */
.badge {
    display: inline-block;
    background: var(--accent-dim);
    color: var(--accent);
    padding: 0.3rem 0.8rem;
    border-radius: 50px;
    font-size: 0.8rem;
    font-weight: 500;
    margin-bottom: 1rem;
}

/* ===================== Tech Tags ===================== */
.tech-tag,
.skill-tag {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    padding: 0.6rem 1.2rem;
    border-radius: 50px;
    font-size: 0.95rem;
    font-family: 'JetBrains Mono', monospace;
    transition: all 0.3s ease;
    cursor: default;
    box-shadow: var(--shadow);
}

.tech-tag:hover,
.skill-tag:hover {
    border-color: var(--accent);
    background: var(--accent-dim);
    transform: translateY(-4px) scale(1.05);
    box-shadow: 0 8px 25px var(--accent-glow);
}

.tech-tag:active,
.skill-tag:active {
    transform: translateY(-2px) scale(0.98);
}

/* ===================== Content Section (Project Pages) ===================== */
.content-section {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.content-section h2 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--accent);
}

.content-section p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.content-section ul {
    color: var(--text-secondary);
    padding-left: 1.5rem;
}

.content-section li {
    margin-bottom: 0.75rem;
}

/* ===================== Highlight Box ===================== */
.highlight-box {
    background: var(--accent-dim);
    border-left: 3px solid var(--accent);
    padding: 1.5rem;
    border-radius: 0 12px 12px 0;
    margin: 1.5rem 0;
}

.highlight-box p {
    color: var(--text-primary);
    margin: 0;
}

/* ===================== Tech Stack Container ===================== */
.tech-stack {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1rem;
}

.tech-stack .tech-tag {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    padding: 0.5rem 1rem;
    border-radius: 50px;
    font-size: 0.9rem;
}

/* ===================== Project Navigation ===================== */
.nav-projects {
    display: flex;
    justify-content: space-between;
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
}

.nav-projects a {
    color: var(--text-secondary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: color 0.3s ease;
}

.nav-projects a:hover {
    color: var(--accent);
}

/* ===================== Footer ===================== */
footer {
    text-align: center;
    padding: 1rem 2rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-top: 1px solid var(--glass-border);
    z-index: 100;
}

/* ===================== Animations ===================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate {
    animation: fadeInUp 0.8s ease forwards;
}

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }

/* Scroll Reveal */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

@keyframes wave {
    0%, 100% { transform: rotate(0deg); }
    25% { transform: rotate(-20deg); }
    75% { transform: rotate(20deg); }
}

/* ===================== Responsive Design ===================== */
@media (max-width: 1200px) {
    section {
        padding: 5rem 2rem;
    }
}

@media (max-width: 900px) {
    nav {
        padding: 1rem 1.5rem;
    }

    .nav-links {
        display: none;
    }

    section {
        padding: 4rem 1.5rem;
    }

    .section-header h2 {
        font-size: 2rem;
    }
}

@media (max-width: 768px) {
    nav {
        padding: 1rem 1.5rem;
    }
    
    .theme-toggle .icon {
        width: 28px;
        height: 28px;
        font-size: 0.9rem;
    }
}

@media (max-width: 480px) {
    section {
        padding: 3rem 1rem;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }
}