/* =====================================================
   WHITE CLINIC — Landing Page Phân Tích Da
   Bộ màu thương hiệu:
   - Dark Teal (chủ đạo): #004D4D
   - Coral Pastel (bổ trợ): #FFE0CC
   - Rose Gold Pastel (sang trọng): #FFD9C6
   - Creamy Off-White (nền): #FEF9F2
   - Deep Slate (text): #333333
   ===================================================== */

/* === IMPORT FONT === */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&display=swap');

/* === CSS VARIABLES === */
:root {
    --teal: #004D4D;
    --teal-light: #006666;
    --teal-dark: #003838;
    --teal-50: rgba(0, 77, 77, 0.05);
    --teal-10: rgba(0, 77, 77, 0.10);
    --coral: #FFE0CC;
    --coral-dark: #FFD0B0;
    --rose-gold: #FFD9C6;
    --rose-gold-dark: #FFC8A8;
    --cream: #FEF9F2;
    --cream-dark: #FDF0E0;
    --slate: #333333;
    --slate-light: #555555;
    --slate-lighter: #888888;
    --white: #FFFFFF;

    --font: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;

    --shadow-xs: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.10);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.16);
    --shadow-teal: 0 4px 20px rgba(0, 77, 77, 0.25);
    --shadow-coral: 0 4px 20px rgba(255, 224, 204, 0.5);

    --radius-sm: 8px;
    --radius: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --radius-full: 9999px;

    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s ease;
    --transition-slow: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* === RESET & BASE === */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font);
    color: var(--slate);
    background: var(--cream);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    text-decoration: none;
    color: inherit;
}

/* === CONTAINER === */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* === SECTION COMMON === */
.section-title {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    font-weight: 800;
    color: var(--teal);
    text-align: center;
    margin-bottom: 0.5em;
    letter-spacing: -0.02em;
    line-height: 1.2;
}

.section-subtitle {
    font-size: clamp(1rem, 2vw, 1.15rem);
    color: var(--slate-light);
    text-align: center;
    max-width: 700px;
    margin: 0 auto 3rem;
    font-weight: 400;
    line-height: 1.7;
}

/* === ANIMATIONS === */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(40px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-60px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(60px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

@keyframes shimmer {
    0% { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

.animate-on-scroll {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* === BUTTONS === */
.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 36px;
    background: var(--teal);
    color: var(--white);
    border: none;
    border-radius: var(--radius-full);
    font-family: var(--font);
    font-size: 0.95rem;
    font-weight: 700;
    letter-spacing: 0.03em;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow-teal);
    position: relative;
    overflow: hidden;
    text-transform: uppercase;
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.15), transparent);
    transition: left 0.5s ease;
}

.btn-primary:hover {
    background: var(--teal-light);
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0, 77, 77, 0.35);
}

.btn-primary:hover::before {
    left: 100%;
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-lg {
    padding: 18px 48px;
    font-size: 1.05rem;
}

.btn-outline {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 36px;
    background: transparent;
    color: var(--white);
    border: 2px solid rgba(255,255,255,0.5);
    border-radius: var(--radius-full);
    font-family: var(--font);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.btn-outline:hover {
    background: rgba(255,255,255,0.15);
    border-color: var(--white);
    transform: translateY(-2px);
}

/* === HEADER === */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: var(--transition);
    background: transparent;
}

.header.scrolled {
    background: rgba(0, 77, 77, 0.97);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 10px 0;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.15);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    width: 40px;
    height: 40px;
}

.logo-text {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

.logo-name {
    font-size: 1.2rem;
    font-weight: 800;
    color: var(--white);
    letter-spacing: 0.1em;
}

.logo-tagline {
    font-size: 0.65rem;
    color: rgba(255, 255, 255, 0.7);
    letter-spacing: 0.15em;
    text-transform: uppercase;
    font-weight: 500;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
    list-style: none;
}

.nav-links a {
    color: rgba(255, 255, 255, 0.85);
    font-weight: 500;
    font-size: 0.9rem;
    transition: var(--transition-fast);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--coral);
    transition: width 0.3s ease;
}

.nav-links a:hover {
    color: var(--white);
}

.nav-links a:hover::after {
    width: 100%;
}

.nav-cta {
    padding: 10px 24px !important;
    font-size: 0.85rem !important;
    background: var(--coral) !important;
    color: var(--teal) !important;
    box-shadow: none !important;
}

.nav-cta:hover {
    background: var(--rose-gold) !important;
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-btn span {
    width: 26px;
    height: 2px;
    background: var(--white);
    transition: var(--transition);
    border-radius: 2px;
}

/* === HERO SECTION === */
.hero {
    min-height: 100vh;
    background: linear-gradient(135deg, var(--teal-dark) 0%, var(--teal) 40%, var(--teal-light) 100%);
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    padding: 100px 0 60px;
}

/* Hiệu ứng pattern nền hero */
.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 30% 70%, rgba(255, 224, 204, 0.08) 0%, transparent 50%),
                radial-gradient(circle at 70% 30%, rgba(255, 217, 198, 0.06) 0%, transparent 50%);
    pointer-events: none;
}

/* Hình trang trí nền */
.hero::after {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 800px;
    height: 800px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(255, 224, 204, 0.05) 0%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-text {
    animation: slideInLeft 1s ease forwards;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    background: rgba(255, 224, 204, 0.15);
    border: 1px solid rgba(255, 224, 204, 0.3);
    border-radius: var(--radius-full);
    color: var(--coral);
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 24px;
    backdrop-filter: blur(4px);
}

.hero-badge::before {
    content: '✨';
}

.hero h1 {
    font-size: clamp(2.2rem, 5vw, 3.5rem);
    font-weight: 900;
    color: var(--white);
    line-height: 1.15;
    margin-bottom: 20px;
    letter-spacing: -0.02em;
}

.hero h1 span {
    color: var(--coral);
}

.hero-desc {
    font-size: clamp(1rem, 2vw, 1.15rem);
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.7;
    margin-bottom: 36px;
    max-width: 520px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hero-stats {
    display: flex;
    gap: 32px;
    margin-top: 48px;
    padding-top: 32px;
    border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.hero-stat {
    text-align: center;
}

.hero-stat-number {
    font-size: 2rem;
    font-weight: 800;
    color: var(--coral);
    line-height: 1;
}

.hero-stat-label {
    font-size: 0.8rem;
    color: rgba(255, 255, 255, 0.6);
    margin-top: 4px;
    font-weight: 500;
}

.hero-image {
    animation: slideInRight 1s ease 0.2s forwards;
    opacity: 0;
    position: relative;
}

.hero-image img {
    border-radius: var(--radius-lg);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    width: 100%;
    height: auto;
    object-fit: cover;
}

.hero-image::before {
    content: '';
    position: absolute;
    top: -20px;
    right: -20px;
    width: 100%;
    height: 100%;
    border: 2px solid rgba(255, 224, 204, 0.2);
    border-radius: var(--radius-lg);
    z-index: -1;
}

/* === ABOUT SECTION === */
.about {
    padding: 100px 0;
    background: var(--cream);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    margin-top: 48px;
}

.about-image {
    position: relative;
}

.about-image img {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    width: 100%;
}

.about-image::after {
    content: '';
    position: absolute;
    bottom: -16px;
    left: -16px;
    width: 120px;
    height: 120px;
    background: var(--coral);
    border-radius: var(--radius);
    z-index: -1;
    opacity: 0.5;
}

.about-text p {
    font-size: 1.05rem;
    color: var(--slate-light);
    margin-bottom: 32px;
    line-height: 1.8;
}

.light-sources {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.light-card {
    padding: 20px;
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid rgba(0, 77, 77, 0.06);
}

.light-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--teal);
}

.light-card-icon {
    width: 40px;
    height: 40px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
    margin-bottom: 12px;
}

.light-card-icon.lc1 { background: rgba(255, 215, 0, 0.12); }
.light-card-icon.lc2 { background: rgba(0, 77, 77, 0.08); }
.light-card-icon.lc3 { background: rgba(138, 43, 226, 0.08); }
.light-card-icon.lc4 { background: rgba(255, 182, 193, 0.15); }

.light-card h4 {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--teal);
    margin-bottom: 6px;
}

.light-card p {
    font-size: 0.8rem;
    color: var(--slate-lighter);
    line-height: 1.5;
    margin-bottom: 0;
}

/* === PROCESS SECTION === */
.process {
    padding: 100px 0;
    background: var(--white);
}

.process-steps {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-top: 48px;
    position: relative;
}

/* Đường kết nối giữa các bước */
.process-steps::before {
    content: '';
    position: absolute;
    top: 55px;
    left: calc(12.5% + 12px);
    right: calc(12.5% + 12px);
    height: 2px;
    background: linear-gradient(90deg, var(--coral), var(--rose-gold), var(--coral));
    z-index: 0;
}

.step-card {
    text-align: center;
    padding: 32px 20px;
    position: relative;
    z-index: 1;
}

.step-number {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--teal), var(--teal-light));
    color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    font-weight: 800;
    margin: 0 auto 20px;
    box-shadow: var(--shadow-teal);
    position: relative;
}

.step-number::after {
    content: '';
    position: absolute;
    width: 72px;
    height: 72px;
    border-radius: 50%;
    border: 2px solid var(--coral);
    opacity: 0.4;
}

.step-icon {
    font-size: 2.2rem;
    margin-bottom: 16px;
    display: block;
}

.step-card h3 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--teal);
    margin-bottom: 10px;
}

.step-card p {
    font-size: 0.88rem;
    color: var(--slate-lighter);
    line-height: 1.6;
}

/* === FEATURES SECTION === */
.features {
    padding: 100px 0;
    background: linear-gradient(180deg, var(--cream) 0%, var(--white) 100%);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-top: 48px;
}

.feature-card {
    padding: 36px 28px;
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid rgba(0, 77, 77, 0.04);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--teal), var(--coral));
    opacity: 0;
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.feature-card:hover::before {
    opacity: 1;
}

.feature-icon {
    width: 60px;
    height: 60px;
    border-radius: 16px;
    background: linear-gradient(135deg, var(--teal-50), var(--teal-10));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--teal);
    margin-bottom: 10px;
}

.feature-card p {
    font-size: 0.9rem;
    color: var(--slate-lighter);
    line-height: 1.65;
}

/* === BENEFITS SECTION === */
.benefits {
    padding: 100px 0;
    background: linear-gradient(135deg, var(--teal-dark) 0%, var(--teal) 50%, var(--teal-light) 100%);
    position: relative;
    overflow: hidden;
}

.benefits::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 20% 80%, rgba(255, 224, 204, 0.06) 0%, transparent 50%),
                radial-gradient(circle at 80% 20%, rgba(255, 217, 198, 0.04) 0%, transparent 50%);
    pointer-events: none;
}

.benefits .section-title {
    color: var(--white);
}

.benefits .section-subtitle {
    color: rgba(255, 255, 255, 0.7);
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-top: 48px;
    position: relative;
    z-index: 1;
}

.benefit-card {
    text-align: center;
    padding: 40px 24px;
    border-radius: var(--radius-lg);
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    transition: var(--transition);
}

.benefit-card:hover {
    background: rgba(255, 255, 255, 0.12);
    transform: translateY(-6px);
    border-color: rgba(255, 224, 204, 0.3);
}

.benefit-icon {
    width: 72px;
    height: 72px;
    border-radius: 20px;
    background: linear-gradient(135deg, rgba(255, 224, 204, 0.15), rgba(255, 217, 198, 0.1));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin: 0 auto 20px;
}

.benefit-card h3 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 10px;
}

.benefit-card p {
    font-size: 0.88rem;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.65;
}

/* === CTA SECTION === */
.cta-section {
    padding: 100px 0;
    background: linear-gradient(135deg, var(--coral) 0%, var(--rose-gold) 50%, var(--coral-dark) 100%);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.cta-section::before {
    content: '';
    position: absolute;
    top: -100px;
    right: -100px;
    width: 400px;
    height: 400px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    pointer-events: none;
}

.cta-section::after {
    content: '';
    position: absolute;
    bottom: -80px;
    left: -80px;
    width: 300px;
    height: 300px;
    border-radius: 50%;
    background: rgba(0, 77, 77, 0.05);
    pointer-events: none;
}

.cta-section h2 {
    font-size: clamp(1.8rem, 4vw, 2.8rem);
    font-weight: 900;
    color: var(--teal);
    margin-bottom: 16px;
    letter-spacing: -0.02em;
    position: relative;
    z-index: 1;
}

.cta-section p {
    font-size: clamp(1rem, 2vw, 1.15rem);
    color: var(--slate-light);
    max-width: 600px;
    margin: 0 auto 36px;
    line-height: 1.7;
    position: relative;
    z-index: 1;
}

.cta-section .btn-primary {
    position: relative;
    z-index: 1;
    animation: pulse 2s ease-in-out infinite;
}

.cta-section .btn-primary:hover {
    animation: none;
}

/* === FOOTER === */
.footer {
    padding: 60px 0 30px;
    background: var(--teal-dark);
    color: rgba(255, 255, 255, 0.8);
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr;
    gap: 48px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-logo .logo-name {
    font-size: 1.4rem;
    margin-bottom: 4px;
}

.footer-logo .logo-tagline {
    margin-bottom: 16px;
    display: block;
}

.footer-logo p {
    font-size: 0.9rem;
    line-height: 1.7;
    color: rgba(255, 255, 255, 0.6);
    max-width: 340px;
}

.footer h4 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.footer-contact-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 14px;
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.7);
}

.footer-contact-item .icon {
    width: 20px;
    text-align: center;
    flex-shrink: 0;
    margin-top: 2px;
}

.footer-bottom {
    text-align: center;
    padding-top: 24px;
    font-size: 0.82rem;
    color: rgba(255, 255, 255, 0.4);
}

/* === MODAL / POPUP === */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 30, 30, 0.6);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: var(--white);
    border-radius: var(--radius-xl);
    padding: 48px 40px;
    max-width: 480px;
    width: 100%;
    position: relative;
    transform: translateY(20px) scale(0.95);
    transition: var(--transition-slow);
    box-shadow: var(--shadow-xl);
}

.modal-overlay.active .modal {
    transform: translateY(0) scale(1);
}

.modal-close {
    position: absolute;
    top: 16px;
    right: 20px;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--cream);
    border: none;
    font-size: 1.4rem;
    color: var(--slate);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
}

.modal-close:hover {
    background: var(--coral);
    color: var(--teal);
}

.modal-header {
    text-align: center;
    margin-bottom: 32px;
}

.modal-header h2 {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--teal);
    margin-bottom: 8px;
}

.modal-header p {
    font-size: 0.9rem;
    color: var(--slate-lighter);
}

.form-group {
    margin-bottom: 20px;
    position: relative;
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--slate);
    margin-bottom: 6px;
}

.form-group input {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid rgba(0, 77, 77, 0.1);
    border-radius: var(--radius);
    font-family: var(--font);
    font-size: 0.95rem;
    color: var(--slate);
    background: var(--cream);
    transition: var(--transition-fast);
    outline: none;
}

.form-group input:focus {
    border-color: var(--teal);
    background: var(--white);
    box-shadow: 0 0 0 4px rgba(0, 77, 77, 0.08);
}

.form-group input::placeholder {
    color: var(--slate-lighter);
}

.form-group .error-msg {
    font-size: 0.78rem;
    color: #e53e3e;
    margin-top: 4px;
    display: none;
}

.form-group.error input {
    border-color: #e53e3e;
}

.form-group.error .error-msg {
    display: block;
}

.form-submit {
    width: 100%;
    margin-top: 8px;
}

.form-note {
    text-align: center;
    font-size: 0.78rem;
    color: var(--slate-lighter);
    margin-top: 16px;
}

/* Thông báo thành công */
.success-message {
    text-align: center;
    display: none;
}

.success-message.show {
    display: block;
}

.success-icon {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--teal), var(--teal-light));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    margin: 0 auto 20px;
    color: var(--white);
}

.success-message h3 {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--teal);
    margin-bottom: 8px;
}

.success-message p {
    font-size: 0.95rem;
    color: var(--slate-lighter);
    line-height: 1.6;
}

/* Trạng thái loading */
.btn-loading {
    pointer-events: none;
    opacity: 0.7;
}

.btn-loading::after {
    content: '';
    width: 18px;
    height: 18px;
    border: 2px solid transparent;
    border-top-color: var(--white);
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
    margin-left: 8px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* === RESPONSIVE === */

/* Tablet */
@media (max-width: 1024px) {
    .hero-content {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }

    .hero-text {
        order: 1;
    }

    .hero-image {
        order: 2;
        max-width: 500px;
        margin: 0 auto;
    }

    .hero-desc {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-buttons {
        justify-content: center;
    }

    .hero-stats {
        justify-content: center;
    }

    .hero-image::before {
        display: none;
    }

    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .process-steps {
        grid-template-columns: repeat(2, 1fr);
    }

    .process-steps::before {
        display: none;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .benefits-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .nav-links {
        display: none;
    }

    .mobile-menu-btn {
        display: flex;
    }
}

/* Mobile */
@media (max-width: 640px) {
    .hero {
        padding: 80px 0 40px;
    }

    .hero h1 {
        font-size: 1.8rem;
    }

    .hero-stats {
        gap: 20px;
    }

    .hero-stat-number {
        font-size: 1.5rem;
    }

    .process-steps {
        grid-template-columns: 1fr;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .benefits-grid {
        grid-template-columns: 1fr;
    }

    .light-sources {
        grid-template-columns: 1fr;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .modal {
        padding: 32px 24px;
    }

    .modal-header h2 {
        font-size: 1.25rem;
    }

    .btn-lg {
        padding: 15px 32px;
        font-size: 0.95rem;
    }

    .footer-grid {
        text-align: center;
    }

    .footer-logo p {
        margin: 0 auto;
    }

    .footer-contact-item {
        justify-content: center;
    }
}

/* Hiệu ứng scroll cho header */
@media (prefers-reduced-motion: reduce) {
    .animate-on-scroll {
        opacity: 1;
        transform: none;
        transition: none;
    }

    .hero-text,
    .hero-image {
        animation: none;
        opacity: 1;
    }

    .cta-section .btn-primary {
        animation: none;
    }
}