:root {
    --bg-dark: #08080c;
    --card-bg: rgba(30, 30, 45, 0.5);
    --glass-border: rgba(255, 255, 255, 0.08);
    --spanish-red: #ff3e3e;
    --spanish-yellow: #ffcc00;
    --text-white: #ffffff;
    --text-muted: #b0b0cc;
    --neon-glow: 0 0 15px rgba(255, 62, 62, 0.3);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Outfit', 'Inter', sans-serif;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-white);
    min-height: 100vh;
    background: radial-gradient(circle at 0% 0%, #1a0a0a 0%, #08080c 100%);
    display: flex;
    overflow-x: hidden;
}

/* Sidebar */
.sidebar {
    width: 250px;
    height: 100vh;
    background: rgba(15, 15, 25, 0.8);
    backdrop-filter: blur(20px);
    border-right: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    padding: 2.5rem 1.5rem;
    position: sticky;
    top: 0;
}

.logo {
    font-size: 1.6rem;
    font-weight: 800;
    margin-bottom: 3rem;
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo span {
    background: linear-gradient(90deg, var(--spanish-red), var(--spanish-yellow));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    list-style: none;
    flex-grow: 1;
}

.nav-item {
    padding: 14px 18px;
    border-radius: 12px;
    margin-bottom: 10px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 15px;
    color: var(--text-muted);
    transition: var(--transition);
}

.nav-item:hover,
.nav-item.active {
    background: rgba(255, 62, 62, 0.1);
    color: var(--text-white);
    box-shadow: var(--neon-glow);
}

.nav-item.active {
    border-left: 3px solid var(--spanish-red);
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 3rem;
    max-width: 1200px;
    margin: 0 auto;
}

header {
    margin-bottom: 4rem;
}

header h1 {
    font-size: 3rem;
    font-weight: 800;
    letter-spacing: -1px;
}

header p {
    color: var(--text-muted);
    font-size: 1.2rem;
    margin-top: 0.5rem;
}

/* Grid Layout */
.section-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2.5rem;
    margin-bottom: 4rem;
}

.glass-card {
    background: var(--card-bg);
    backdrop-filter: blur(15px);
    border: 1px solid var(--glass-border);
    border-radius: 28px;
    padding: 2.5rem;
    transition: var(--transition);
}

.glass-card:hover {
    transform: translateY(-5px);
    border-color: rgba(255, 255, 255, 0.2);
}

.card-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 12px;
}

.card-title i {
    color: var(--spanish-yellow);
}

/* Tables */
.verb-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

.verb-table th {
    text-align: left;
    padding: 10px;
    color: var(--spanish-yellow);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.verb-table td {
    padding: 12px 10px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.verb-table tr:last-child td {
    border-bottom: none;
}

.accent-text {
    color: var(--spanish-red);
    font-weight: 700;
}

/* Quiz UI */
.quiz-container {
    max-width: 700px;
    margin: 0 auto;
}

.quiz-question {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 2rem;
    text-align: center;
}

.options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.option-btn {
    padding: 1.5rem;
    border-radius: 16px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    color: var(--text-white);
    font-size: 1.1rem;
    cursor: pointer;
    transition: var(--transition);
}

.option-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--spanish-yellow);
}

.option-btn.correct {
    background: rgba(0, 255, 127, 0.2);
    border-color: #00ff7f;
}

.option-btn.wrong {
    background: rgba(255, 62, 62, 0.2);
    border-color: var(--spanish-red);
}

/* Utilities */
.btn-primary {
    background: linear-gradient(45deg, var(--spanish-red), var(--spanish-yellow));
    border: none;
    padding: 12px 24px;
    border-radius: 12px;
    color: white;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary:hover {
    transform: scale(1.05);
    box-shadow: 0 10px 20px rgba(255, 62, 62, 0.3);
}

.hidden {
    display: none;
}

/* Responsive */
@media (max-width: 900px) {
    body {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
    }

    .main-content {
        padding: 1.5rem;
    }
}