/* Apple-Style Design System for studying.works */

:root {
    --bg: #0a0a1a;
    --bg-lighter: #1e1b4b;
    --muted: #9aa3b2;
    --accent: #7c3aed;
    --accent-purple: #a855f7;
    --accent-blue: #6366f1;
    --glass: rgba(255, 255, 255, 0.06);
    --border: rgba(255, 255, 255, 0.08);
    --hover: rgba(255, 255, 255, 0.1);
}

* {
    box-sizing: border-box;
}

html, body {
    height: 100%;
    scroll-behavior: smooth;
    margin: 0;
    padding: 0;
}

body {
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--bg);
    color: white;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography */
.heading-xl {
    font-size: clamp(3rem, 8vw, 7rem);
    font-weight: 900;
    line-height: 1.05;
    letter-spacing: -0.03em;
}

.heading-lg {
    font-size: clamp(2.5rem, 4vw, 4rem);
    font-weight: 900;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.heading-md {
    font-size: clamp(2rem, 3vw, 3rem);
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -0.02em;
}

.heading-sm {
    font-size: clamp(1.5rem, 2vw, 2rem);
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.01em;
}

.body-lg {
    font-size: 1.25rem;
    line-height: 1.6;
    color: var(--muted);
}

.body-md {
    font-size: 1rem;
    line-height: 1.6;
    color: var(--muted);
}

.eyebrow {
    font-size: 1rem;
    font-weight: 700;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Gradient Text */
.gradient-text {
    background: linear-gradient(135deg, #ffffff 0%, #e0e7ff 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.gradient-text-accent {
    background: linear-gradient(135deg, var(--accent), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Buttons */
.btn-primary {
    background: linear-gradient(135deg, #7c3aed 0%, #a855f7 100%);
    color: white;
    padding: 18px 40px;
    border-radius: 16px;
    font-weight: 700;
    font-size: 1.1rem;
    border: none;
    cursor: pointer;
    box-shadow: 0 20px 50px rgba(124, 58, 237, 0.4);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: inline-block;
    text-decoration: none;
    text-align: center;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 25px 60px rgba(124, 58, 237, 0.5);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: white;
    padding: 17px 38px;
    border-radius: 16px;
    font-weight: 600;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: inline-block;
    text-decoration: none;
    text-align: center;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(255, 255, 255, 0.2);
}

.btn-small {
    padding: 12px 24px;
    font-size: 0.95rem;
}

.btn-danger {
    background: linear-gradient(135deg, #ef4444 0%, #dc2626 100%);
    box-shadow: 0 10px 30px rgba(239, 68, 68, 0.3);
}

.btn-danger:hover {
    box-shadow: 0 15px 40px rgba(239, 68, 68, 0.4);
}

/* Cards */
.card {
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.05) 0%, rgba(255, 255, 255, 0.02) 100%);
    border: 1px solid var(--border);
    border-radius: 24px;
    padding: 32px;
    position: relative;
    overflow: hidden;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.card:hover {
    transform: translateY(-4px);
    border-color: rgba(255, 255, 255, 0.15);
    box-shadow: 0 30px 80px rgba(0, 0, 0, 0.5);
}

.card-3d {
    transform-style: preserve-3d;
    cursor: pointer;
}

.card-glass {
    background: var(--glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
}

.card-gradient-accent {
    background: linear-gradient(135deg, rgba(124, 58, 237, 0.15) 0%, rgba(168, 85, 247, 0.15) 100%);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

/* Nav Bar */
.nav-bar {
    background: rgba(11, 11, 13, 0.7);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 50;
    padding: 1.5rem 0;
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    text-decoration: none;
    transition: transform 0.3s;
}

.nav-logo:hover {
    transform: scale(1.05);
}

.nav-links {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.nav-link {
    color: rgba(255, 255, 255, 0.8);
    padding: 0.75rem 1rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
}

.nav-link:hover {
    color: white;
    background: rgba(255, 255, 255, 0.1);
}

.nav-link.active {
    color: white;
    background: rgba(255, 255, 255, 0.1);
}

/* Glowing Orbs */
.glow-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.2;
    pointer-events: none;
    animation: float 8s ease-in-out infinite;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
    }
    50% {
        transform: translate(20px, -20px) scale(1.05);
    }
}

/* Stats Cards */
.stat-card {
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.05) 0%, rgba(255, 255, 255, 0.02) 100%);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 24px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.stat-card:hover {
    transform: translateY(-4px);
    border-color: rgba(255, 255, 255, 0.15);
}

.stat-icon {
    font-size: 2.5rem;
    margin-bottom: 12px;
    display: block;
    filter: drop-shadow(0 4px 12px rgba(124, 58, 237, 0.3));
}

.stat-value {
    font-size: 2rem;
    font-weight: 900;
    color: white;
    line-height: 1;
    margin-bottom: 8px;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--muted);
    font-weight: 600;
}

/* Progress Bars */
.progress-bar {
    height: 12px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 999px;
    overflow: hidden;
    position: relative;
}

.progress-fill {
    height: 100%;
    border-radius: 999px;
    transition: width 1s ease;
    background: linear-gradient(90deg, var(--accent), var(--accent-purple));
}

/* Input Fields */
.input {
    width: 100%;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 14px 18px;
    color: white;
    font-size: 1rem;
    font-family: inherit;
    transition: all 0.3s;
}

.input:focus {
    outline: none;
    border-color: var(--accent);
    background: rgba(255, 255, 255, 0.08);
    box-shadow: 0 0 0 3px rgba(14, 165, 164, 0.1);
}

.input::placeholder {
    color: var(--muted);
}

.textarea {
    min-height: 120px;
    resize: vertical;
}

/* Select */
.select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%239aa3b2' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 20px;
    padding-right: 40px;
}

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 6px 14px;
    border-radius: 999px;
    font-size: 0.85rem;
    font-weight: 700;
    background: var(--glass);
    border: 1px solid var(--border);
    color: var(--muted);
}

.badge-accent {
    background: rgba(124, 58, 237, 0.15);
    border-color: var(--accent);
    color: var(--accent);
}

.badge-purple {
    background: rgba(168, 85, 247, 0.15);
    border-color: var(--accent-purple);
    color: var(--accent-purple);
}

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
}

.container-narrow {
    max-width: 900px;
}

/* Section */
.section {
    padding: 8vh 2rem;
    position: relative;
}

.section-lg {
    padding: 12vh 2rem;
}

/* Grid */
.grid {
    display: grid;
    gap: 2rem;
}

.grid-2 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-4 {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

/* Loading Spinner */
.spinner {
    display: inline-block;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 4px solid rgba(255, 255, 255, 0.08);
    border-top-color: white;
    animation: spin 1s linear infinite;
}

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

/* Animations */
.fade-in {
    animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.slide-in {
    animation: slideIn 0.6s ease-out;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Utilities */
.text-center {
    text-align: center;
}

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

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mt-6 { margin-top: 3rem; }
.mt-8 { margin-top: 4rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mb-6 { margin-bottom: 3rem; }
.mb-8 { margin-bottom: 4rem; }

.p-4 { padding: 2rem; }
.p-6 { padding: 3rem; }
.p-8 { padding: 4rem; }

.gap-2 { gap: 1rem; }
.gap-3 { gap: 1.5rem; }
.gap-4 { gap: 2rem; }

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        gap: 0.25rem;
    }

    .nav-link {
        padding: 0.5rem 0.75rem;
        font-size: 0.9rem;
    }

    .container {
        padding: 0 1rem;
    }

    .section {
        padding: 4vh 1rem;
    }

    .grid {
        gap: 1rem;
    }

    .stat-card {
        padding: 16px;
    }

    .card {
        padding: 20px;
    }
}

/* Dark Mode Support (default is dark) */
@media (prefers-color-scheme: light) {
    /* Keep dark theme regardless of system preference */
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

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

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* Selection */
::selection {
    background: var(--accent);
    color: white;
}

::-moz-selection {
    background: var(--accent);
    color: white;
}