/* Apple-Inspired "Light AI" Theme */
:root {
    --bg-color: #fbfbfd; /* Apple-like off-white */
    --card-bg: #ffffff;
    --primary-color: #0071e3; /* Apple Blue */
    --primary-gradient: linear-gradient(135deg, #0071e3 0%, #42a1ff 100%);
    --text-primary: #1d1d1f;
    --text-secondary: #86868b;
    --accent-color: #ff2d55; /* Apple Pink/Red for accents */
    --success-color: #34c759;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.12);
    --shadow-3d: 0 10px 20px rgba(0, 0, 0, 0.1), 0 6px 6px rgba(0, 0, 0, 0.1);
    --radius-lg: 24px;
    --radius-xl: 32px;
    --nav-height: 70px;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
    line-height: 1.5;
}

/* Navbar */
.glass-nav {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    height: var(--nav-height);
    transition: all 0.3s ease;
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.4rem;
    color: var(--text-primary) !important;
    letter-spacing: -0.5px;
}

.nav-link {
    color: var(--text-secondary) !important;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s ease;
}

.nav-link:hover, .nav-link.active {
    color: var(--primary-color) !important;
}

/* Buttons */
.btn-primary {
    background: var(--primary-color);
    border: none;
    border-radius: 980px; /* Pill shape */
    padding: 12px 32px;
    font-weight: 600;
    font-size: 1rem;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

.btn-primary:hover {
    background: #0077ed;
    transform: translateY(-2px) scale(1.02);
    box-shadow: var(--shadow-md);
}

.btn-outline-light {
    color: var(--primary-color);
    border: 2px solid rgba(0, 113, 227, 0.2);
    background: transparent;
    border-radius: 980px;
    padding: 10px 30px;
    font-weight: 600;
}

.btn-outline-light:hover {
    background: rgba(0, 113, 227, 0.05);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* Cards & Containers */
.glass-card {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(0, 0, 0, 0.02);
    box-shadow: var(--shadow-md);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    overflow: hidden;
}

.glass-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    color: var(--text-primary);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.text-gradient {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.text-muted {
    color: var(--text-secondary) !important;
}

/* Hero Section */
.hero-section {
    padding-top: 140px;
    padding-bottom: 100px;
    background: radial-gradient(circle at 50% 0%, #eef2ff 0%, #fbfbfd 60%);
    position: relative;
    overflow: hidden;
}

.hero-image-container {
    position: relative;
    z-index: 2;
}

.hero-image-container img {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-3d);
    transform: perspective(1000px) rotateY(-5deg) rotateX(2deg);
    transition: transform 0.5s ease;
}

.hero-image-container:hover img {
    transform: perspective(1000px) rotateY(0deg) rotateX(0deg);
}

/* 3D Floating Elements */
.floating-3d {
    animation: float3d 6s ease-in-out infinite;
}

@keyframes float3d {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(2deg); }
}

/* Feature Cards */
.feature-card {
    background: #ffffff;
    border-radius: var(--radius-lg);
    padding: 40px 30px;
    height: 100%;
    border: 1px solid rgba(0,0,0,0.04);
    box-shadow: var(--shadow-sm);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

.icon-box {
    width: 64px;
    height: 64px;
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    font-size: 28px;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e7eb 100%);
    color: var(--primary-color);
    box-shadow: inset 2px 2px 5px rgba(255,255,255,0.8), inset -2px -2px 5px rgba(0,0,0,0.05);
}

/* Auth Pages */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #fbfbfd;
    padding: 20px;
}

.auth-card {
    width: 100%;
    max-width: 420px;
    background: #ffffff;
    padding: 48px;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
}

/* Form Controls */
.form-label {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.form-control {
    background: #f5f5f7;
    border: 1px solid transparent;
    border-radius: 12px;
    padding: 14px 16px;
    font-size: 1rem;
    color: var(--text-primary);
    transition: all 0.2s ease;
}

.form-control:focus {
    background: #ffffff;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(0, 113, 227, 0.15);
    color: var(--text-primary);
}

/* Dashboard */
.dashboard-container {
    padding-top: calc(var(--nav-height) + 40px);
    padding-bottom: 60px;
    min-height: 100vh;
    background: #fbfbfd;
}

/* File Manager */
.file-item {
    background: #ffffff;
    border: 1px solid rgba(0,0,0,0.06);
    border-radius: 16px;
    padding: 16px;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: var(--shadow-sm);
    transition: all 0.2s ease;
}

.file-item:hover {
    transform: scale(1.01);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

#answerFilesList:empty::before {
    content: "Drag & drop files here or click 'Add Answer File'";
    display: block;
    padding: 40px;
    text-align: center;
    color: var(--text-secondary);
    background: #f5f5f7;
    border: 2px dashed #d2d2d7;
    border-radius: 16px;
    font-weight: 500;
}

/* Footer */
.footer {
    background: #ffffff;
    border-top: 1px solid rgba(0,0,0,0.05);
    padding: 40px 0;
}

/* Animations */
[data-aos] {
    pointer-events: none;
}
[data-aos].aos-animate {
    pointer-events: auto;
}