/* ========== CSS VARIABLES ========== */
:root {
  --bg: #fdfdfd;
  --text: #1a1a1a;
  --accent: #00bcd4;
  --header-bg: #111;
  --section-alt-bg: #f5f7fa;
  --hero-gradient: linear-gradient(135deg, #00bcd4, #008c9e);
  --btn-bg: #fff;
  --btn-text: #008c9e;
}

/* Dark mode */
.dark-mode {
  --bg: #0f1116;
  --text: #eaeaea;
  --accent: #00bcd4;
  --header-bg: #1b1b1b;
  --section-alt-bg: #16181d;
  --hero-gradient: linear-gradient(135deg, #007b8c, #005f70);
  --btn-bg: #222;
  --btn-text: #e3f8fa;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  transition: background 0.3s ease, color 0.3s ease;
}

/* ========== CONTAINER ========== */
.container {
  width: 90%;
  max-width: 1100px;
  margin: 0 auto;
}

.container.narrow {
  max-width: 800px;
}

/* ========== HEADER ========== */
header {
  background: var(--header-bg);
  color: white;
  position: sticky;
  top: 0;
  z-index: 10;
  transition: background 0.3s ease;
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

.logo {
  font-weight: 700;
  font-size: 1.5rem;
}

/* Navbar */
nav ul {
  display: flex;
  list-style: none;
  gap: 1.5rem;
  margin: 0;
  padding: 0;
}

nav a {
  text-decoration: none;
  color: white;
  font-weight: 500;
  transition: color 0.3s ease;
}

nav a:hover {
  color: var(--accent);
}

/* Header buttons */
.header-buttons {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

#menu-toggle, #theme-toggle {
  background: none;
  border: none;
  color: white;
  font-size: 1.4rem;
  cursor: pointer;
  transition: opacity 0.3s ease;
}

#menu-toggle:hover, #theme-toggle:hover {
  opacity: 0.8;
}

/* ========== HERO ========== */
.hero {
  background: var(--hero-gradient);
  color: white;
  text-align: center;
  padding: 100px 20px;
  transition: background 0.4s ease;
}

.hero h2 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  font-weight: 700;
}

.hero h2 span {
  color: #e3f8fa;
}

.hero p {
  font-size: 1.1rem;
  margin-bottom: 2rem;
  opacity: 0.9;
}

.hero .btn {
  background: var(--btn-bg);
  color: var(--btn-text);
  text-decoration: none;
  padding: 0.75rem 1.5rem;
  border-radius: 6px;
  font-weight: 600;
  transition: all 0.3s ease;
}

.hero .btn:hover {
  background: #e3f8fa;
}

/* ========== SECTIONS ========== */
.section {
  padding: 80px 20px;
  text-align: center;
}

.section h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
}

.section p {
  font-size: 1.05rem;
  color: var(--text);
}

.section.alt {
  background: var(--section-alt-bg);
  transition: background 0.3s ease;
}

/* ========== FOOTER ========== */
footer {
  background: var(--header-bg);
  color: white;
  text-align: center;
  padding: 1.5rem 0;
  font-size: 0.95rem;
  transition: background 0.3s ease;
}

/* ========== RESPONSIVE ========== */
@media (max-width: 700px) {
  nav ul {
    display: none;
    flex-direction: column;
    background: #222;
    position: absolute;
    top: 60px;
    right: 0;
    width: 220px;
    padding: 1rem;
    border-radius: 0 0 0 8px;
  }

  nav ul.show {
    display: flex;
  }

  #menu-toggle {
    display: block;
  }
}