:root {
    --primary: #6366f1;
    --accent: #f59e0b;
    --bg: #fafafe;
    --bg-card: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --success: #10b981;
    --gradient-start: #6366f1;
    --gradient-end: #a855f7;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    overflow-x: hidden;
}

/* ===== Navigation ===== */
.nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
}
.nav-inner {
    max-width: 1200px; margin: 0 auto; padding: 16px 32px;
    display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
    display: flex; align-items: center; gap: 10px;
    font-size: 1.3rem; font-weight: 700; color: var(--primary); text-decoration: none;
}
.logo-icon {
    width: 38px; height: 38px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    color: #fff; font-size: 1.2rem;
}
.nav-links { display: flex; list-style: none; gap: 32px; }
.nav-links a {
    text-decoration: none; color: var(--text-light); font-size: 0.95rem; font-weight: 500;
    transition: color 0.2s;
}
.nav-links a:hover { color: var(--primary); }
.btn-nav {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: #fff !important; padding: 10px 24px; border-radius: 50px; font-weight: 600 !important;
    transition: transform 0.2s, box-shadow 0.2s !important;
}
.btn-nav:hover { transform: translateY(-2px); box-shadow: 0 8px 25px rgba(99,102,241,0.35); }

/* ===== Hero ===== */
.hero {
    min-height: 100vh; display: flex; align-items: center;
    position: relative; overflow: hidden; padding-top: 80px;
}
.hero-bg { position: absolute; inset: 0; z-index: 0; }
.hero-bg::before {
    content: ''; position: absolute; top: -30%; right: -15%;
    width: 700px; height: 700px;
    background: radial-gradient(circle, rgba(99,102,241,0.08) 0%, transparent 70%);
    border-radius: 50%;
}
.hero-bg::after {
    content: ''; position: absolute; bottom: -20%; left: -10%;
    width: 500px; height: 500px;
    background: radial-gradient(circle, rgba(168,85,247,0.06) 0%, transparent 70%);
    border-radius: 50%;
}
.hero-inner {
    max-width: 1200px; margin: 0 auto; padding: 40px 32px;
    display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: center;
    position: relative; z-index: 1;
}
.hero-badge {
    display: inline-flex; align-items: center; gap: 8px;
    background: linear-gradient(135deg, rgba(99,102,241,0.1), rgba(168,85,247,0.1));
    border: 1px solid rgba(99,102,241,0.2);
    padding: 8px 18px; border-radius: 50px;
    font-size: 0.9rem; font-weight: 600; color: var(--primary); margin-bottom: 24px;
}
.badge-dot {
    width: 8px; height: 8px; background: var(--success); border-radius: 50%;
    animation: pulse-dot 2s infinite;
}
@keyframes pulse-dot {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.5); }
}
.hero h1 { font-size: 3.2rem; font-weight: 800; line-height: 1.2; margin-bottom: 20px; }
.hero h1 .highlight {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.hero p { font-size: 1.15rem; color: var(--text-light); margin-bottom: 36px; max-width: 480px; }
.hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }

.btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 14px 32px; border-radius: 50px; font-size: 1rem; font-weight: 600;
    text-decoration: none; cursor: pointer; border: none; transition: all 0.25s ease;
}
.btn-primary {
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: #fff; box-shadow: 0 4px 20px rgba(99,102,241,0.3);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 30px rgba(99,102,241,0.4); }
.btn-outline { background: transparent; color: var(--primary); border: 2px solid var(--border); }
.btn-outline:hover { border-color: var(--primary); background: rgba(99,102,241,0.04); }

/* Hero Card Visual */
.hero-visual { display: flex; justify-content: center; align-items: center; }
.hero-card-stack { position: relative; width: 380px; height: 460px; }
.hero-card {
    position: absolute; background: var(--bg-card); border-radius: 24px;
    padding: 28px; box-shadow: 0 20px 60px rgba(0,0,0,0.08);
    border: 1px solid var(--border); transition: all 0.3s ease;
}
.hero-card:nth-child(1) { top: 0; left: 0; width: 100%; height: 100%; z-index: 3; }
.hero-card:nth-child(2) { top: 20px; left: 15px; width: 92%; height: 90%; z-index: 2; opacity: 0.6; }
.hero-card:nth-child(3) { top: 40px; left: 30px; width: 84%; height: 80%; z-index: 1; opacity: 0.3; }
.card-day-badge {
    display: inline-flex; align-items: center; gap: 6px;
    background: linear-gradient(135deg, rgba(16,185,129,0.12), rgba(99,102,241,0.12));
    padding: 6px 14px; border-radius: 20px;
    font-size: 0.85rem; font-weight: 700; color: var(--success); margin-bottom: 20px;
}
.card-habits { display: flex; flex-direction: column; gap: 14px; }
.habit-item {
    display: flex; align-items: center; gap: 12px;
    padding: 14px 18px; background: #f8fafc; border-radius: 14px; transition: all 0.2s;
}
.habit-item:hover { background: #f1f5f9; }
.habit-icon {
    width: 40px; height: 40px; border-radius: 12px;
    display: flex; align-items: center; justify-content: center; font-size: 1.1rem;
}
.habit-icon.water { background: #e0f2fe; } .habit-icon.read { background: #fef3c7; }
.habit-icon.exercise { background: #d1fae5; } .habit-icon.meditate { background: #ede9fe; }
.habit-check {
    width: 24px; height: 24px; border-radius: 50%;
    display: flex; align-items: center; justify-content: center; font-size: 0.75rem; margin-left: auto;
}
.habit-check.done { background: var(--success); color: #fff; }
.habit-check.pending { background: #f1f5f9; border: 2px solid #e2e8f0; }
.habit-name { font-weight: 600; font-size: 0.95rem; }
.habit-name small { color: var(--text-light); font-weight: 400; margin-left: 6px; }

/* ===== Section Common ===== */
section { padding: 100px 32px; }
.section-inner { max-width: 1100px; margin: 0 auto; }
.section-label {
    display: inline-block; font-size: 0.85rem; font-weight: 700;
    text-transform: uppercase; letter-spacing: 0.1em;
    color: var(--primary); margin-bottom: 12px;
}
.section-title { font-size: 2.4rem; font-weight: 800; margin-bottom: 16px; line-height: 1.3; }
.section-subtitle {
    font-size: 1.1rem; color: var(--text-light); max-width: 600px; margin-bottom: 48px;
}

/* ===== About ===== */
#about { background: var(--bg-card); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.about-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
.about-card {
    background: var(--bg); border-radius: 20px; padding: 32px;
    border: 1px solid var(--border); transition: all 0.3s ease;
}
.about-card:hover {
    transform: translateY(-4px); box-shadow: 0 12px 40px rgba(0,0,0,0.06);
    border-color: rgba(99,102,241,0.2);
}
.about-card-icon {
    width: 52px; height: 52px; border-radius: 14px;
    display: flex; align-items: center; justify-content: center; font-size: 1.4rem; margin-bottom: 18px;
}
.about-card-icon.purple { background: linear-gradient(135deg, #e0e7ff, #ede9fe); }
.about-card-icon.amber { background: linear-gradient(135deg, #fef3c7, #fde68a); }
.about-card-icon.green { background: linear-gradient(135deg, #d1fae5, #a7f3d0); }
.about-card h3 { font-size: 1.2rem; font-weight: 700; margin-bottom: 8px; }
.about-card p { color: var(--text-light); font-size: 0.95rem; }

/* ===== Features ===== */
.features-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.feature-item {
    display: flex; gap: 18px; padding: 28px; background: var(--bg-card);
    border-radius: 18px; border: 1px solid var(--border); transition: all 0.3s ease;
}
.feature-item:hover {
    border-color: rgba(99,102,241,0.25); box-shadow: 0 8px 30px rgba(0,0,0,0.04);
}
.feature-num {
    width: 44px; height: 44px; min-width: 44px; border-radius: 12px;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    color: #fff; display: flex; align-items: center; justify-content: center;
    font-weight: 700; font-size: 1rem;
}
.feature-content h4 { font-size: 1.05rem; font-weight: 700; margin-bottom: 6px; }
.feature-content p { color: var(--text-light); font-size: 0.9rem; }

/* ===== Plan ===== */
#plan { background: var(--bg-card); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.phase-timeline { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.phase-card {
    background: var(--bg); border-radius: 20px; padding: 32px;
    border: 1px solid var(--border); transition: all 0.3s ease;
}
.phase-card:hover { border-color: rgba(99,102,241,0.3); box-shadow: 0 8px 30px rgba(0,0,0,0.05); }
.phase-header { display: flex; align-items: center; gap: 12px; margin-bottom: 16px; }
.phase-num {
    width: 48px; height: 48px; border-radius: 14px;
    display: flex; align-items: center; justify-content: center;
    font-weight: 800; font-size: 1.2rem; color: #fff;
}
.phase-num.p1 { background: linear-gradient(135deg, #6366f1, #818cf8); }
.phase-num.p2 { background: linear-gradient(135deg, #8b5cf6, #a78bfa); }
.phase-num.p3 { background: linear-gradient(135deg, #a855f7, #c084fc); }
.phase-card h3 { font-size: 1.15rem; font-weight: 700; }
.phase-card .days { color: var(--primary); font-weight: 700; font-size: 0.9rem; }
.phase-list { list-style: none; display: flex; flex-direction: column; gap: 10px; }
.phase-list li {
    padding-left: 20px; position: relative; color: var(--text-light); font-size: 0.9rem;
}
.phase-list li::before {
    content: ''; position: absolute; left: 0; top: 8px;
    width: 6px; height: 6px; border-radius: 50%; background: var(--primary); opacity: 0.5;
}

/* ===== Backend ===== */
.backend-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.backend-stat {
    text-align: center; padding: 32px 20px; background: var(--bg-card);
    border-radius: 18px; border: 1px solid var(--border);
}
.backend-stat .stat-value {
    font-size: 2.4rem; font-weight: 800;
    background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
    -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.backend-stat .stat-label { color: var(--text-light); font-size: 0.9rem; margin-top: 6px; }

.backend-services { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-top: 48px; }
.service-card {
    background: var(--bg-card); border-radius: 18px; padding: 30px;
    border: 1px solid var(--border); transition: all 0.3s ease;
}
.service-card:hover { transform: translateY(-3px); box-shadow: 0 12px 40px rgba(0,0,0,0.06); }
.service-card-icon {
    width: 48px; height: 48px; border-radius: 12px;
    background: linear-gradient(135deg, rgba(99,102,241,0.1), rgba(168,85,247,0.1));
    display: flex; align-items: center; justify-content: center; font-size: 1.3rem; margin-bottom: 18px;
}
.service-card h4 { font-weight: 700; margin-bottom: 8px; font-size: 1.05rem; }
.service-card p { color: var(--text-light); font-size: 0.9rem; }

/* Tech Stack */
.tech-tags { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 16px; }
.tech-tag {
    padding: 8px 18px; background: #f1f5f9; border-radius: 50px;
    font-size: 0.85rem; font-weight: 600; color: var(--text-light); transition: all 0.2s;
}
.tech-tag:hover { background: rgba(99,102,241,0.1); color: var(--primary); }

/* ===== CTA ===== */
#cta {
    background: linear-gradient(135deg, #1e1b4b, #312e81, #3730a3);
    color: #fff; text-align: center;
}
#cta .section-title { color: #fff; }
#cta .section-subtitle { color: rgba(255,255,255,0.7); margin: 0 auto 36px; }
.cta-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.btn-white { background: #fff; color: var(--primary); padding: 14px 36px; }
.btn-white:hover { transform: translateY(-2px); box-shadow: 0 8px 30px rgba(255,255,255,0.25); }

/* ===== Footer ===== */
footer { background: #0f172a; color: rgba(255,255,255,0.7); padding: 60px 32px 32px; }
.footer-inner {
    max-width: 1100px; margin: 0 auto;
    display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px;
}
.footer-brand h3 { color: #fff; font-size: 1.2rem; margin-bottom: 12px; }
.footer-brand p { font-size: 0.9rem; line-height: 1.7; }
.footer-col h4 { color: #fff; font-size: 0.95rem; font-weight: 700; margin-bottom: 16px; }
.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: 10px; }
.footer-col ul li a {
    color: rgba(255,255,255,0.6); text-decoration: none; font-size: 0.9rem; transition: color 0.2s;
}
.footer-col ul li a:hover { color: rgba(255,255,255,0.9); }
.footer-bottom {
    max-width: 1100px; margin: 40px auto 0; padding-top: 24px;
    border-top: 1px solid rgba(255,255,255,0.1);
    display: flex; justify-content: space-between; font-size: 0.85rem; flex-wrap: wrap; gap: 12px;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
    .hero-inner { grid-template-columns: 1fr; text-align: center; }
    .hero p { margin: 0 auto 36px; }
    .hero-buttons { justify-content: center; }
    .hero-visual { display: none; }
    .hero h1 { font-size: 2.2rem; }
    .about-grid { grid-template-columns: 1fr; }
    .features-grid { grid-template-columns: 1fr; }
    .phase-timeline { grid-template-columns: 1fr; }
    .backend-grid { grid-template-columns: repeat(2, 1fr); }
    .backend-services { grid-template-columns: 1fr; }
    .footer-inner { grid-template-columns: 1fr 1fr; }
    .nav-links { display: none; }
    section { padding: 60px 20px; }
}
@media (max-width: 500px) {
    .backend-grid { grid-template-columns: 1fr; }
    .footer-inner { grid-template-columns: 1fr; }
    .hero h1 { font-size: 1.8rem; }
    .section-title { font-size: 1.8rem; }
    .hero-buttons, .cta-buttons { flex-direction: column; align-items: center; }
}