:root {
    --bg-dark: #0f172a;
    --bg-card: #1e293b;
    --primary: #38bdf8;
    --primary-glow: #0284c7;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --input-bg: #0b0f19;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Montserrat', sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

h1, h2, h3, .logo {
    font-family: 'Fira Code', monospace;
}

/* Header & Navigation */
header {
    background-color: rgba(15, 23, 42, 0.9);
    padding: 1.5rem 5%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid #334155;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.logo {
    font-size: 1.8rem;
    font-weight: 700;
}

.logo span {
    color: var(--primary);
}

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

.tab-btn {
    background: transparent;
    color: var(--text-muted);
    border: none;
    font-family: 'Montserrat', sans-serif;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    padding: 0.5rem 1rem;
    transition: all 0.3s ease;
    border-bottom: 2px solid transparent;
}

.tab-btn:hover {
    color: var(--text-main);
}

.tab-btn.active {
    color: var(--primary);
    border-bottom: 2px solid var(--primary);
    text-shadow: 0 0 10px rgba(56, 189, 248, 0.5);
}

.nav-auth-btn {
    border: 1px solid var(--primary);
    border-radius: 6px;
    margin-left: 1rem;
}

.nav-auth-btn:hover {
    background-color: rgba(56, 189, 248, 0.1);
}

.nav-auth-btn.active {
    background-color: var(--primary);
    color: var(--bg-dark);
    text-shadow: none;
}

/* Main Layout */
main {
    flex: 1;
    padding: 3rem 5%;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.tab-content {
    display: none;
    animation: fadeIn 0.4s ease-in-out;
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Hero Section */
.hero {
    text-align: center;
    margin-bottom: 4rem;
}

.hero h1 {
    font-size: 3.2rem;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.hero h1 span {
    color: var(--primary);
    text-shadow: 0 0 25px rgba(56, 189, 248, 0.3);
}

.hero p {
    font-size: 1.2rem;
    color: var(--text-muted);
    max-width: 850px;
    margin: 0 auto;
}

/* Info Sections */
.section-title {
    text-align: center;
    margin-bottom: 2.5rem;
}

.section-title h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.section-title p, .section-subtitle-text {
    color: var(--text-muted);
    text-align: center;
    margin-bottom: 2rem;
    font-size: 1.1rem;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2rem;
    margin-bottom: 5rem;
}

.card {
    background-color: var(--bg-card);
    padding: 2rem;
    border-radius: 12px;
    border: 1px solid #334155;
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(2, 132, 199, 0.15);
    border-color: var(--primary);
}

.card h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: var(--primary);
}

.card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* Tech Stack Section */
.tech-stack-section {
    background: linear-gradient(135deg, rgba(30, 41, 59, 0.5), rgba(15, 23, 42, 0.8));
    padding: 3rem 2rem;
    border-radius: 16px;
    border: 1px solid #334155;
    text-align: center;
}

.tech-stack-section h2 {
    font-size: 1.8rem;
    margin-bottom: 2rem;
}

.stack-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
}

.stack-item {
    background-color: var(--bg-dark);
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    border: 1px solid #334155;
    font-family: 'Fira Code', monospace;
    font-size: 1rem;
}

/* Lessons List */
.lesson-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    max-width: 900px;
    margin: 0 auto;
}

.lesson-item {
    display: flex;
    align-items: flex-start;
    background-color: var(--bg-card);
    padding: 2rem;
    border-radius: 12px;
    border-left: 4px solid var(--primary);
    border-top: 1px solid #334155;
    border-right: 1px solid #334155;
    border-bottom: 1px solid #334155;
}

.lesson-number {
    font-family: 'Fira Code', monospace;
    font-size: 2.2rem;
    font-weight: 700;
    color: #475569;
    margin-right: 2rem;
    line-height: 1;
}

.lesson-details h3 {
    font-size: 1.3rem;
    margin-bottom: 0.75rem;
    color: var(--text-main);
}

.lesson-details p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* Videos Coming Soon */
.coming-soon {
    text-align: center;
    background-color: var(--bg-card);
    padding: 5rem 2rem;
    border-radius: 16px;
    border: 1px dashed var(--primary);
    max-width: 800px;
    margin: 0 auto;
}

.coming-soon .icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.coming-soon h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
}

.coming-soon p {
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto 2rem auto;
}

.progress-bar {
    width: 100%;
    max-width: 450px;
    height: 12px;
    background-color: #0f172a;
    border-radius: 6px;
    margin: 0 auto 1rem auto;
    overflow: hidden;
    border: 1px solid #334155;
}

.progress-fill {
    height: 100%;
    width: 85%;
    background: linear-gradient(90deg, var(--primary-glow), var(--primary));
    border-radius: 6px;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { opacity: 0.8; }
    50% { opacity: 1; box-shadow: 0 0 15px var(--primary); }
    100% { opacity: 0.8; }
}

/* Pseudo Auth Section */
.auth-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem 0;
}

.auth-container {
    background-color: var(--bg-card);
    width: 100%;
    max-width: 450px;
    padding: 2.5rem;
    border-radius: 16px;
    border: 1px solid #334155;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.auth-tabs {
    display: flex;
    border-bottom: 1px solid #334155;
    margin-bottom: 2rem;
}

.auth-toggle-btn {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-family: 'Montserrat', sans-serif;
    font-size: 1.1rem;
    font-weight: 600;
    padding: 0.75rem;
    cursor: pointer;
    transition: all 0.3s ease;
    border-bottom: 2px solid transparent;
}

.auth-toggle-btn.active {
    color: var(--primary);
    border-bottom: 2px solid var(--primary);
}

.auth-form {
    display: none;
    flex-direction: column;
    gap: 1.25rem;
}

.auth-form.active {
    display: flex;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-size: 0.85rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group input[type="password"] {
    background-color: var(--input-bg);
    border: 1px solid #334155;
    padding: 0.85rem 1rem;
    border-radius: 8px;
    color: var(--text-main);
    font-family: 'Montserrat', sans-serif;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 10px rgba(56, 189, 248, 0.2);
}

.form-actions {
    display: flex;
    justify-content: flex-end;
}

.forgot-pass {
    color: var(--primary);
    font-size: 0.85rem;
    text-decoration: none;
}

.forgot-pass:hover {
    text-decoration: underline;
}

.checkbox-group {
    flex-direction: row;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    cursor: pointer;
}

.checkbox-group input {
    cursor: pointer;
}

.primary-btn {
    background-color: var(--primary);
    color: var(--bg-dark);
    border: none;
    padding: 1rem;
    border-radius: 8px;
    font-family: 'Montserrat', sans-serif;
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 0.5rem;
}

.primary-btn:hover {
    background-color: #7dd3fc;
    box-shadow: 0 0 15px rgba(56, 189, 248, 0.4);
    transform: translateY(-1px);
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    background-color: var(--bg-card);
    color: var(--text-muted);
    border-top: 1px solid #334155;
    font-size: 0.9rem;
}