:root {
    --bg: #ffffff;
    --text: #1a1a1a;
    --text-soft: #4a5568;
    --card-bg: #f7fafc; 
    --accent: #5046e5;
    --border: #edf2f7;
}

[data-theme="dark"] {
    --bg: #0b0e14;
    --text: #f7fafc;
    --text-soft: #a0aec0;
    --card-bg: #1a202c;
    --border: #2d3748;
}

* { 
    margin: 0; 
    padding: 0; 
    box-sizing: border-box; 
    transition: background 0.3s ease, color 0.3s ease, border-color 0.3s ease; 
}

body { 
    font-family: 'Space Grotesk', sans-serif; 
    background: var(--bg); 
    color: var(--text); 
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 8%;
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
}

.nav-right { display: flex; align-items: center; gap: 30px; }

.nav-links { display: flex; gap: 25px; list-style: none; }

.nav-links a {
    text-decoration: none;
    color: var(--text);
    font-size: 0.95rem;
    font-weight: 500;
    opacity: 0.8;
}

.nav-links a:hover { opacity: 1; color: var(--accent); }

.logo {
    font-size: 1.6rem;
    font-weight: 800;
    color: var(--text);
    text-decoration: none; 
    letter-spacing: -1px; 
    display: flex;
    align-items: center;
    transition: transform 0.2s ease;
}

.logo span {
    color: var(--accent);
    margin-left: 2px;
}

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

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

.theme-btn {
    background: var(--card-bg);
    border: 1px solid var(--border);
    cursor: pointer;
    width: 40px;
    height: 40px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}

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

.hero { 
    text-align: center; 
    padding: 100px 5% 60px; 
    max-width: 900px;
    margin: 0 auto;
}

.hero h1 { 
    font-size: clamp(2.5rem, 7vw, 5rem); 
    font-weight: 700; 
    line-height: 1.1;
    margin-bottom: 20px; 
}

.hero h1 span { color: var(--accent); }
.hero p { color: var(--text-soft); font-size: 1.1rem; }

.search-container {
    position: relative;
    margin-right: 20px;
}

#roadmap-search {
    background: var(--card-bg);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 10px 15px 10px 40px;
    border-radius: 12px;
    width: 250px;
    outline: none;
    font-family: inherit;
    transition: all 0.3s ease;
}

#roadmap-search:focus {
    width: 320px;
    border-color: var(--accent);
    box-shadow: 0 0 15px rgba(80, 70, 229, 0.1);
}

.search-icon {
    position: absolute;
    left: 15px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.9rem;
    opacity: 0.5;
}

@media (max-width: 768px) {
    .nav-right { gap: 15px; }
    #roadmap-search { width: 150px; }
    #roadmap-search:focus { width: 180px; }
    .nav-links { display: none; }
}

.quiz-option {
    display: block;
    width: 100%;
    padding: 15px 20px;
    margin: 10px 0;
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: 12px;
    color: var(--text);
    cursor: pointer;
    text-align: left;
    font-size: 1rem;
    transition: 0.3s all ease;
}

.quiz-container {
    max-width: 600px;
    margin: 0 auto;
    text-align: left;
}

.quiz-option {
    display: block;
    width: 100%;
    padding: 18px 25px; 
    margin: 12px 0;
    background: var(--card-bg);
    border: 2px solid var(--border);
    border-radius: 15px;
    color: var(--text) !important;
    cursor: pointer;
    text-align: left;
    font-size: 1rem;
    font-weight: 500;
    transition: 0.3s all ease;
}

.quiz-option:hover {
    border-color: var(--accent);
    background: var(--bg);
    transform: translateY(-2px);
}

.quiz-container h3 {
    color: var(--text);
    line-height: 1.4;
}

.roadmap-step h4 {
    color: var(--text);
}

.roadmap-step p { 
    color: var(--text-soft); 
}

.card {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.card h3 {
    color: var(--text);
}

.quiz-option:hover {
    border-color: var(--accent);
    background: rgba(80, 70, 229, 0.05);
    transform: translateX(5px);
}

.quiz-option.correct {
    background: #10b981 !important; 
    color: white;
    border-color: #059669;
}

.quiz-option.wrong {
    background: #ef4444 !important; 
    color: white;
    border-color: #dc2626;
}

.score-display {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent);
    text-align: center;
}

.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 25px;
    padding: 20px 8%;
}

.card {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 24px;
    border: 1px solid var(--border);
    cursor: pointer;
    transition: 0.3s transform ease;
}

.card:hover { 
    transform: translateY(-8px); 
    border-color: var(--accent); 
}

.tag { 
    font-size: 0.7rem; 
    text-transform: uppercase; 
    color: var(--accent); 
    font-weight: 700; 
    display: block;
    margin-bottom: 10px;
}

.viewer { padding: 50px 8%; }

#content-box {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 30px;
    padding: 40px;
    min-height: 200px;
}

.roadmap-step {
    padding: 20px;
    margin-bottom: 15px;
    border-left: 3px solid var(--accent);
    background: rgba(80, 70, 229, 0.05);
    border-radius: 0 12px 12px 0;
    animation: fadeIn 0.5s ease both;
}

.roadmap-step p { color: var(--text-soft); }

@keyframes fadeIn { 
    from { opacity: 0; transform: translateY(10px); } 
    to { opacity: 1; transform: translateY(0); } 
}

.library-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 30px;
    padding: 40px 8%;
}

.lib-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 30px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.lib-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(80, 70, 229, 0.1);
    border-color: var(--accent);
}

.lib-badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 8px;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    background: rgba(80, 70, 229, 0.1);
    color: var(--accent);
    margin-bottom: 15px;
    width: fit-content;
}

.lib-title {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: var(--text);
}

.lib-desc {
    color: var(--text-soft);
    font-size: 0.95rem;
    margin-bottom: 25px;
}

.lib-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    background: var(--accent);
    color: white;
    text-decoration: none;
    padding: 12px;
    border-radius: 12px;
    font-weight: 600;
    font-size: 0.9rem;
    transition: opacity 0.2s;
}

.lib-btn:hover {
    opacity: 0.9;
}

.quiz-start-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 200px;
}

.quiz-container {
    padding: 20px;
}

.quiz-progress {
    color: var(--accent);
    font-weight: 600;
    margin-bottom: 10px;
}

.quiz-title {
    color: var(--text);
    margin-bottom: 20px;
    font-size: 1.2rem;
}

.options-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.quiz-option {
    background: var(--card-bg) !important;
    color: var(--text) !important;         
    border: 1px solid var(--border);
    padding: 15px 20px;
    border-radius: 12px;
    cursor: pointer;
    text-align: left;
    font-family: inherit;
    font-size: 1rem;
    transition: 0.3s all ease;
}

.quiz-option:hover {
    border-color: var(--accent);
    background: rgba(80, 70, 229, 0.05) !important;
}

.btn-start-large {
    background: var(--accent);
    color: white;
    border: none;
    padding: 20px 50px;
    font-size: 1.5rem;
    font-weight: 700;
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 10px 20px rgba(80, 70, 229, 0.3);
}

.btn-start-large:hover {
    transform: scale(1.05);
    box-shadow: 0 15px 30px rgba(80, 70, 229, 0.4);
    filter: brightness(1.1);
}

.btn-start-large:active {
    transform: scale(0.98);
}