:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #1e293b;
    --accent-color: #3b82f6;
    --background-light: #f8fafc;
    --text-color: #334155;
    --text-dark: #0f172a;
    --white: #ffffff;
    --gradient-bg: linear-gradient(135deg, #eff6ff 0%, #f8fafc 100%);
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --card-hover-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

body {
    font-family: 'Inter', sans-serif;
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--background-light);
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

h1, h2, h3 {
    color: var(--text-dark);
    font-weight: 700;
    line-height: 1.2;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    text-align: center;
}

p {
    margin-bottom: 1rem;
}

a {
    text-decoration: none;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--white);
    box-shadow: 0 4px 6px rgba(37, 99, 235, 0.2);
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 6px 8px rgba(37, 99, 235, 0.3);
}

/* Hero Section */
.hero {
    background: var(--gradient-bg);
    padding: 80px 0;
    text-align: center;
}

.hero .subtitle {
    font-size: 1.25rem;
    color: var(--text-color);
    max-width: 700px;
    margin: 0 auto 2rem;
}

/* Section General */
.section {
    padding: 80px 0;
}

/* Problem Section */
.problem {
    background-color: var(--white);
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.card {
    background: var(--white);
    padding: 30px;
    border-radius: 12px;
    border: 1px solid #e2e8f0;
    transition: all 0.3s ease;
}

.card:hover {
    box-shadow: var(--card-hover-shadow);
    border-color: var(--accent-color);
}

.card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.summary {
    text-align: center;
    margin-top: 2rem;
    font-weight: 500;
    font-size: 1.1rem;
}

/* Solution Section */
.solution {
    background-color: #f1f5f9;
    text-align: center;
}

.result-box {
    background: var(--white);
    padding: 20px;
    border-radius: 8px;
    display: inline-block;
    margin-top: 1rem;
    border-left: 4px solid var(--primary-color);
    box-shadow: var(--card-shadow);
}

/* How it works */
.how-it-works {
    background-color: var(--white);
}

.steps {
    display: flex;
    justify-content: space-between;
    gap: 30px;
    flex-wrap: wrap;
}

.step {
    flex: 1;
    min-width: 280px;
    text-align: center;
}

.step-number {
    width: 50px;
    height: 50px;
    background-color: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 auto 1rem;
}

.tip {
    text-align: center;
    margin-top: 2rem;
    color: var(--text-color);
    font-style: italic;
    background: #fffbeb;
    padding: 10px;
    border-radius: 6px;
    display: inline-block;
}

/* Effect Section */
.effect {
    background: linear-gradient(to right, #1e293b, #0f172a);
    color: var(--white);
    text-align: center;
}

.effect h2 {
    color: var(--white);
}

.stat {
    margin: 2rem 0;
}

.big-number {
    font-size: 4rem;
    font-weight: 800;
    color: #60a5fa;
    display: block;
    line-height: 1;
}

.desc {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* Forms Section */
.forms-section {
    background-color: #f8fafc;
}

.tabs {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
    gap: 10px;
}

.tab-btn {
    padding: 10px 20px;
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    border-radius: 30px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
}

.tab-btn.active, .tab-btn:hover {
    background: var(--primary-color);
    color: var(--white);
}

.tab-content {
    display: none;
    max-width: 600px;
    margin: 0 auto;
    background: var(--white);
    padding: 40px;
    border-radius: 16px;
    box-shadow: var(--card-shadow);
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.5s ease;
}

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

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-dark);
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid #cbd5e1;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.note {
    font-size: 0.9rem;
    color: #64748b;
    margin-top: 1rem;
    text-align: center;
}

.note.important {
    color: #dc2626;
    font-weight: 500;
}

/* Simplicity & Audience */
.simplicity, .audience {
    text-align: center;
    background-color: var(--white);
}

/* Footer */
.footer {
    background-color: var(--secondary-color);
    color: var(--white);
    text-align: center;
    padding: 60px 0;
}

.footer h2 {
    color: var(--white);
    margin-bottom: 1rem;
}

/* Responsive */
@media (max-width: 768px) {
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    .hero { padding: 60px 0; }
    .tab-content { padding: 20px; }
}